Merge pull request #10502 from ydb-platform/mergelibs-241016-1210

Library import 241016-1210

18 files changed, 10678 insertions, 0 deletions

diff --git a/contrib/restricted/boost/filesystem/src/atomic_ref.hpp b/contrib/restricted/boost/filesystem/src/atomic_ref.hpp
new file mode 100644
index 0000000000..6e8208d39e
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/atomic_ref.hpp
@@ -0,0 +1,32 @@
+//  atomic.hpp  ------------------------------------------------------------------------//
+
+//  Copyright 2021 Andrey Semashev
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  See library home page at http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#ifndef BOOST_FILESYSTEM_SRC_ATOMIC_REF_HPP_
+#define BOOST_FILESYSTEM_SRC_ATOMIC_REF_HPP_
+
+#include <boost/filesystem/config.hpp>
+
+#if !defined(BOOST_FILESYSTEM_NO_CXX20_ATOMIC_REF)
+
+#include <atomic>
+
+namespace atomic_ns = std;
+
+#else // !defined(BOOST_FILESYSTEM_NO_CXX20_ATOMIC_REF)
+
+#include <boost/memory_order.hpp>
+#include <boost/atomic/atomic_ref.hpp>
+
+namespace atomic_ns = boost;
+
+#endif // !defined(BOOST_FILESYSTEM_NO_CXX20_ATOMIC_REF)
+
+#endif // BOOST_FILESYSTEM_SRC_ATOMIC_REF_HPP_
diff --git a/contrib/restricted/boost/filesystem/src/atomic_tools.hpp b/contrib/restricted/boost/filesystem/src/atomic_tools.hpp
new file mode 100644
index 0000000000..a60e5d325a
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/atomic_tools.hpp
@@ -0,0 +1,69 @@
+//  atomic_tools.hpp  ------------------------------------------------------------------//
+
+//  Copyright 2021 Andrey Semashev
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  See library home page at http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#ifndef BOOST_FILESYSTEM_SRC_ATOMIC_TOOLS_HPP_
+#define BOOST_FILESYSTEM_SRC_ATOMIC_TOOLS_HPP_
+
+#include <boost/filesystem/config.hpp>
+
+#if !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+
+#include "atomic_ref.hpp"
+
+namespace boost {
+namespace filesystem {
+namespace detail {
+
+//! Atomically loads the value
+template< typename T >
+BOOST_FORCEINLINE T atomic_load_relaxed(T& a)
+{
+    return atomic_ns::atomic_ref< T >(a).load(atomic_ns::memory_order_relaxed);
+}
+
+//! Atomically stores the value
+template< typename T >
+BOOST_FORCEINLINE void atomic_store_relaxed(T& a, T val)
+{
+    atomic_ns::atomic_ref< T >(a).store(val, atomic_ns::memory_order_relaxed);
+}
+
+} // namespace detail
+} // namespace filesystem
+} // namespace boost
+
+#else // !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+
+namespace boost {
+namespace filesystem {
+namespace detail {
+
+//! Atomically loads the value
+template< typename T >
+BOOST_FORCEINLINE T atomic_load_relaxed(T const& a)
+{
+    return a;
+}
+
+//! Atomically stores the value
+template< typename T >
+BOOST_FORCEINLINE void atomic_store_relaxed(T& a, T val)
+{
+    a = val;
+}
+
+} // namespace detail
+} // namespace filesystem
+} // namespace boost
+
+#endif // !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+
+#endif // BOOST_FILESYSTEM_SRC_ATOMIC_TOOLS_HPP_
diff --git a/contrib/restricted/boost/filesystem/src/codecvt_error_category.cpp b/contrib/restricted/boost/filesystem/src/codecvt_error_category.cpp
new file mode 100644
index 0000000000..dc3df54d36
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/codecvt_error_category.cpp
@@ -0,0 +1,120 @@
+//  codecvt_error_category implementation file  ----------------------------------------//
+
+//  Copyright 2009 Beman Dawes
+//  Copyright 2022 Andrey Semashev
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt)
+
+//  Library home page at http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#include "platform_config.hpp"
+
+#include <boost/config/warning_disable.hpp>
+
+#include <boost/filesystem/config.hpp>
+#include <boost/filesystem/detail/path_traits.hpp>
+#include <boost/system/error_category.hpp>
+#include <locale>
+#include <string>
+
+#include "private_config.hpp"
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+//--------------------------------------------------------------------------------------//
+
+namespace boost {
+namespace filesystem {
+
+namespace {
+
+#if (defined(BOOST_GCC) && BOOST_GCC >= 40600) || defined(BOOST_CLANG)
+#pragma GCC diagnostic push
+// '(anonymous namespace)::codecvt_error_cat' has virtual functions but non-virtual destructor
+// This is not a problem as instances of codecvt_error_cat are never destroyed through a pointer to base.
+#pragma GCC diagnostic ignored "-Wnon-virtual-dtor"
+#endif
+
+class codecvt_error_cat final :
+    public boost::system::error_category
+{
+public:
+    // clang up to version 3.8 requires a user-defined default constructor in order to be able to declare a static constant of the error category.
+    BOOST_SYSTEM_CONSTEXPR codecvt_error_cat() noexcept {}
+    const char* name() const noexcept override;
+    std::string message(int ev) const override;
+};
+
+const char* codecvt_error_cat::name() const noexcept
+{
+    return "codecvt";
+}
+
+std::string codecvt_error_cat::message(int ev) const
+{
+    std::string str;
+    switch (ev)
+    {
+    case std::codecvt_base::ok:
+        str = "ok";
+        break;
+    case std::codecvt_base::partial:
+        str = "partial";
+        break;
+    case std::codecvt_base::error:
+        str = "error";
+        break;
+    case std::codecvt_base::noconv:
+        str = "noconv";
+        break;
+    default:
+        str = "unknown error";
+        break;
+    }
+    return str;
+}
+
+#if (defined(BOOST_GCC) && BOOST_GCC >= 40600) || defined(BOOST_CLANG)
+#pragma GCC diagnostic pop
+#endif
+
+} // unnamed namespace
+
+BOOST_FILESYSTEM_DECL boost::system::error_category const& codecvt_error_category() noexcept
+{
+    static
+#if defined(BOOST_SYSTEM_HAS_CONSTEXPR)
+        constexpr
+#else
+        const
+#endif
+        codecvt_error_cat codecvt_error_cat_const;
+    return codecvt_error_cat_const;
+}
+
+// Try to initialize the error category instance as early as possible to make sure it is
+// available during global deinitialization stage. For MSVC, codecvt_error_category() will
+// be called early by MSVC-specific initialization routine in path.cpp.
+#if !defined(BOOST_SYSTEM_HAS_CONSTEXPR) && !defined(_MSC_VER)
+
+namespace {
+
+struct codecvt_error_category_initializer
+{
+    codecvt_error_category_initializer() { boost::filesystem::codecvt_error_category(); }
+};
+
+BOOST_FILESYSTEM_INIT_PRIORITY(BOOST_FILESYSTEM_PATH_GLOBALS_INIT_PRIORITY) BOOST_ATTRIBUTE_UNUSED BOOST_FILESYSTEM_ATTRIBUTE_RETAIN
+const codecvt_error_category_initializer g_codecvt_error_category_initializer;
+
+} // namespace
+
+#endif // !defined(BOOST_SYSTEM_HAS_CONSTEXPR) && !defined(_MSC_VER)
+
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
diff --git a/contrib/restricted/boost/filesystem/src/directory.cpp b/contrib/restricted/boost/filesystem/src/directory.cpp
new file mode 100644
index 0000000000..576a460dd3
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/directory.cpp
@@ -0,0 +1,1772 @@
+//  directory.cpp  --------------------------------------------------------------------//
+
+//  Copyright 2002-2009, 2014 Beman Dawes
+//  Copyright 2001 Dietmar Kuehl
+//  Copyright 2019, 2022-2024 Andrey Semashev
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  See library home page at http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#include "platform_config.hpp"
+
+#include <boost/filesystem/config.hpp>
+#include <boost/filesystem/directory.hpp>
+#include <boost/filesystem/exception.hpp>
+#include <boost/filesystem/operations.hpp>
+#include <boost/filesystem/file_status.hpp>
+
+#include <cstddef>
+#include <cerrno>
+#include <cstring>
+#include <cstdlib> // std::malloc, std::free
+#include <new>     // std::nothrow, std::bad_alloc
+#include <limits>
+#include <string>
+#include <utility> // std::move
+#include <boost/assert.hpp>
+#include <boost/system/error_code.hpp>
+#include <boost/smart_ptr/intrusive_ptr.hpp>
+
+#ifdef BOOST_POSIX_API
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <memory>
+#include <boost/scope/unique_fd.hpp>
+
+#if defined(_POSIX_THREAD_SAFE_FUNCTIONS) && (_POSIX_THREAD_SAFE_FUNCTIONS >= 0) && defined(_SC_THREAD_SAFE_FUNCTIONS) && \
+    !defined(__CYGWIN__) && \
+    !(defined(linux) || defined(__linux) || defined(__linux__)) && \
+    !defined(__ANDROID__) && \
+    (!defined(__hpux) || defined(_REENTRANT)) && \
+    (!defined(_AIX) || defined(__THREAD_SAFE)) && \
+    !defined(__wasm)
+#define BOOST_FILESYSTEM_USE_READDIR_R
+#endif
+
+// At least Mac OS X 10.6 and older doesn't support O_CLOEXEC
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#define BOOST_FILESYSTEM_NO_O_CLOEXEC
+#endif
+
+#include "posix_tools.hpp"
+
+#else // BOOST_WINDOWS_API
+
+#include <cwchar>
+#include <windows.h>
+#include <boost/winapi/basic_types.hpp> // NTSTATUS_
+
+#include "windows_tools.hpp"
+
+#endif // BOOST_WINDOWS_API
+
+#include "atomic_tools.hpp"
+#include "error_handling.hpp"
+#include "private_config.hpp"
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+namespace fs = boost::filesystem;
+using boost::system::error_code;
+using boost::system::system_category;
+
+namespace boost {
+namespace filesystem {
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//                                 directory_entry                                      //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL void directory_entry::refresh_impl(system::error_code* ec) const
+{
+    m_status = filesystem::file_status();
+    m_symlink_status = filesystem::file_status();
+
+    m_symlink_status = detail::symlink_status(m_path, ec);
+
+    if (!filesystem::is_symlink(m_symlink_status))
+    {
+        // Also works if symlink_status fails - set m_status to status_error as well
+        m_status = m_symlink_status;
+    }
+    else
+    {
+        m_status = detail::status(m_path, ec);
+    }
+}
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//                               directory_iterator                                     //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+namespace detail {
+
+#if defined(BOOST_POSIX_API)
+
+//! Opens a directory file and returns a file descriptor. Returns a negative value in case of error.
+boost::scope::unique_fd open_directory(path const& p, directory_options opts, system::error_code& ec)
+{
+    ec.clear();
+
+    int flags = O_DIRECTORY | O_RDONLY | O_NONBLOCK | O_CLOEXEC;
+
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+    if ((opts & directory_options::_detail_no_follow) != directory_options::none)
+        flags |= O_NOFOLLOW;
+#endif
+
+    int res;
+    while (true)
+    {
+        res = ::open(p.c_str(), flags);
+        if (BOOST_UNLIKELY(res < 0))
+        {
+            const int err = errno;
+            if (err == EINTR)
+                continue;
+            ec = system::error_code(err, system::system_category());
+            return boost::scope::unique_fd();
+        }
+
+        break;
+    }
+
+#if defined(BOOST_FILESYSTEM_NO_O_CLOEXEC) && defined(FD_CLOEXEC)
+    boost::scope::unique_fd fd(res);
+
+    res = ::fcntl(fd.get(), F_SETFD, FD_CLOEXEC);
+    if (BOOST_UNLIKELY(res < 0))
+    {
+        const int err = errno;
+        ec = system::error_code(err, system::system_category());
+        return boost::scope::unique_fd();
+    }
+
+    return fd;
+#else
+    return boost::scope::unique_fd(res);
+#endif
+}
+
+#if defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+
+//! Opens a directory file and returns a file descriptor. Returns a negative value in case of error.
+boost::scope::unique_fd openat_directory(int basedir_fd, path const& p, directory_options opts, system::error_code& ec)
+{
+    ec.clear();
+
+    int flags = O_DIRECTORY | O_RDONLY | O_NONBLOCK | O_CLOEXEC;
+
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+    if ((opts & directory_options::_detail_no_follow) != directory_options::none)
+        flags |= O_NOFOLLOW;
+#endif
+
+    int res;
+    while (true)
+    {
+        res = ::openat(basedir_fd, p.c_str(), flags);
+        if (BOOST_UNLIKELY(res < 0))
+        {
+            const int err = errno;
+            if (err == EINTR)
+                continue;
+            ec = system::error_code(err, system::system_category());
+            return boost::scope::unique_fd();
+        }
+
+        break;
+    }
+
+#if defined(BOOST_FILESYSTEM_NO_O_CLOEXEC) && defined(FD_CLOEXEC)
+    boost::scope::unique_fd fd(res);
+
+    res = ::fcntl(fd.get(), F_SETFD, FD_CLOEXEC);
+    if (BOOST_UNLIKELY(res < 0))
+    {
+        const int err = errno;
+        ec = system::error_code(err, system::system_category());
+        return boost::scope::unique_fd();
+    }
+
+    return fd;
+#else
+    return boost::scope::unique_fd(res);
+#endif
+}
+
+#endif // defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+
+#endif // defined(BOOST_POSIX_API)
+
+BOOST_CONSTEXPR_OR_CONST std::size_t dir_itr_imp_extra_data_alignment = 16u;
+
+BOOST_FILESYSTEM_DECL void* dir_itr_imp::operator new(std::size_t class_size, std::size_t extra_size) noexcept
+{
+    if (extra_size > 0)
+        class_size = (class_size + dir_itr_imp_extra_data_alignment - 1u) & ~(dir_itr_imp_extra_data_alignment - 1u);
+    std::size_t total_size = class_size + extra_size;
+
+    // Return nullptr on OOM
+    void* p = std::malloc(total_size);
+    if (BOOST_LIKELY(p != nullptr))
+        std::memset(p, 0, total_size);
+    return p;
+}
+
+BOOST_FILESYSTEM_DECL void dir_itr_imp::operator delete(void* p, std::size_t extra_size) noexcept
+{
+    std::free(p);
+}
+
+BOOST_FILESYSTEM_DECL void dir_itr_imp::operator delete(void* p) noexcept
+{
+    std::free(p);
+}
+
+namespace {
+
+inline void* get_dir_itr_imp_extra_data(dir_itr_imp* imp) noexcept
+{
+    BOOST_CONSTEXPR_OR_CONST std::size_t extra_data_offset = (sizeof(dir_itr_imp) + dir_itr_imp_extra_data_alignment - 1u) & ~(dir_itr_imp_extra_data_alignment - 1u);
+    return reinterpret_cast< unsigned char* >(imp) + extra_data_offset;
+}
+
+#ifdef BOOST_POSIX_API
+
+inline system::error_code dir_itr_close(dir_itr_imp& imp) noexcept
+{
+    if (imp.handle != nullptr)
+    {
+        DIR* h = static_cast< DIR* >(imp.handle);
+        imp.handle = nullptr;
+        int err = 0;
+        if (BOOST_UNLIKELY(::closedir(h) != 0))
+        {
+            err = errno;
+            return system::error_code(err, system::system_category());
+        }
+    }
+
+    return error_code();
+}
+
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+
+// Obtains a file descriptor from the directory iterator
+inline int dir_itr_fd(dir_itr_imp const& imp, system::error_code& ec)
+{
+    int fd = ::dirfd(static_cast< DIR* >(imp.handle));
+    if (BOOST_UNLIKELY(fd < 0))
+    {
+        int err = errno;
+        ec = system::error_code(err, system::system_category());
+    }
+
+    return fd;
+}
+
+#endif // defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+
+#if defined(BOOST_FILESYSTEM_USE_READDIR_R)
+
+// Obtains maximum length of a path, not including the terminating zero
+inline std::size_t get_path_max()
+{
+    // this code is based on Stevens and Rago, Advanced Programming in the
+    // UNIX envirnment, 2nd Ed., ISBN 0-201-43307-9, page 49
+    std::size_t max = 0;
+    errno = 0;
+    long res = ::pathconf("/", _PC_PATH_MAX);
+    if (res < 0)
+    {
+#if defined(PATH_MAX)
+        max = PATH_MAX;
+#else
+        max = 4096;
+#endif
+    }
+    else
+    {
+        max = static_cast< std::size_t >(res); // relative root
+#if defined(PATH_MAX)
+        if (max < PATH_MAX)
+            max = PATH_MAX;
+#endif
+    }
+
+    if ((max + 1) < sizeof(dirent().d_name))
+        max = sizeof(dirent().d_name) - 1;
+
+    return max;
+}
+
+// Returns maximum length of a path, not including the terminating zero
+inline std::size_t path_max()
+{
+    static const std::size_t max = get_path_max();
+    return max;
+}
+
+#endif // BOOST_FILESYSTEM_USE_READDIR_R
+
+// *result set to nullptr on end of directory
+#if !defined(BOOST_FILESYSTEM_USE_READDIR_R)
+inline
+#endif
+int readdir_impl(dir_itr_imp& imp, struct dirent** result)
+{
+    errno = 0;
+
+    struct dirent* p = ::readdir(static_cast< DIR* >(imp.handle));
+    *result = p;
+    if (!p)
+        return errno;
+    return 0;
+}
+
+#if !defined(BOOST_FILESYSTEM_USE_READDIR_R)
+
+inline int invoke_readdir(dir_itr_imp& imp, struct dirent** result)
+{
+    return readdir_impl(imp, result);
+}
+
+#else // !defined(BOOST_FILESYSTEM_USE_READDIR_R)
+
+int readdir_r_impl(dir_itr_imp& imp, struct dirent** result)
+{
+    return ::readdir_r
+    (
+        static_cast< DIR* >(imp.handle),
+        static_cast< struct dirent* >(get_dir_itr_imp_extra_data(&imp)),
+        result
+    );
+}
+
+int readdir_select_impl(dir_itr_imp& imp, struct dirent** result);
+
+typedef int readdir_impl_t(dir_itr_imp& imp, struct dirent** result);
+
+//! Pointer to the actual implementation of the copy_file_data implementation
+readdir_impl_t* readdir_impl_ptr = &readdir_select_impl;
+
+void init_readdir_impl()
+{
+    readdir_impl_t* impl = &readdir_impl;
+    if (::sysconf(_SC_THREAD_SAFE_FUNCTIONS) >= 0)
+        impl = &readdir_r_impl;
+
+    filesystem::detail::atomic_store_relaxed(readdir_impl_ptr, impl);
+}
+
+struct readdir_initializer
+{
+    readdir_initializer()
+    {
+        init_readdir_impl();
+    }
+};
+
+BOOST_FILESYSTEM_INIT_PRIORITY(BOOST_FILESYSTEM_FUNC_PTR_INIT_PRIORITY) BOOST_ATTRIBUTE_UNUSED BOOST_FILESYSTEM_ATTRIBUTE_RETAIN
+const readdir_initializer readdir_init;
+
+int readdir_select_impl(dir_itr_imp& imp, struct dirent** result)
+{
+    init_readdir_impl();
+    return filesystem::detail::atomic_load_relaxed(readdir_impl_ptr)(imp, result);
+}
+
+inline int invoke_readdir(dir_itr_imp& imp, struct dirent** result)
+{
+    return filesystem::detail::atomic_load_relaxed(readdir_impl_ptr)(imp, result);
+}
+
+#endif // !defined(BOOST_FILESYSTEM_USE_READDIR_R)
+
+system::error_code dir_itr_increment(dir_itr_imp& imp, fs::path& filename, fs::file_status& sf, fs::file_status& symlink_sf)
+{
+    dirent* result = nullptr;
+    int err = invoke_readdir(imp, &result);
+    if (BOOST_UNLIKELY(err != 0))
+        return system::error_code(err, system::system_category());
+    if (result == nullptr)
+        return dir_itr_close(imp);
+
+    filename = result->d_name;
+
+#if defined(BOOST_FILESYSTEM_HAS_DIRENT_D_TYPE)
+    if (result->d_type == DT_UNKNOWN) // filesystem does not supply d_type value
+    {
+        sf = symlink_sf = fs::file_status(fs::status_error);
+    }
+    else // filesystem supplies d_type value
+    {
+        if (result->d_type == DT_REG)
+            sf = symlink_sf = fs::file_status(fs::regular_file);
+        else if (result->d_type == DT_DIR)
+            sf = symlink_sf = fs::file_status(fs::directory_file);
+        else if (result->d_type == DT_LNK)
+        {
+            sf = fs::file_status(fs::status_error);
+            symlink_sf = fs::file_status(fs::symlink_file);
+        }
+        else
+        {
+            switch (result->d_type)
+            {
+            case DT_SOCK:
+                sf = symlink_sf = fs::file_status(fs::socket_file);
+                break;
+            case DT_FIFO:
+                sf = symlink_sf = fs::file_status(fs::fifo_file);
+                break;
+            case DT_BLK:
+                sf = symlink_sf = fs::file_status(fs::block_file);
+                break;
+            case DT_CHR:
+                sf = symlink_sf = fs::file_status(fs::character_file);
+                break;
+            default:
+                sf = symlink_sf = fs::file_status(fs::status_error);
+                break;
+            }
+        }
+    }
+#else
+    sf = symlink_sf = fs::file_status(fs::status_error);
+#endif
+    return system::error_code();
+}
+
+system::error_code dir_itr_create(boost::intrusive_ptr< detail::dir_itr_imp >& imp, fs::path const& dir, directory_options opts, directory_iterator_params* params, fs::path& first_filename, fs::file_status&, fs::file_status&)
+{
+    std::size_t extra_size = 0u;
+#if defined(BOOST_FILESYSTEM_USE_READDIR_R)
+    {
+        readdir_impl_t* rdimpl = filesystem::detail::atomic_load_relaxed(readdir_impl_ptr);
+        if (BOOST_UNLIKELY(rdimpl == &readdir_select_impl))
+        {
+            init_readdir_impl();
+            rdimpl = filesystem::detail::atomic_load_relaxed(readdir_impl_ptr);
+        }
+
+        if (rdimpl == &readdir_r_impl)
+        {
+            // According to readdir description, there's no reliable way to predict the length of the d_name string.
+            // It may exceed NAME_MAX and pathconf(_PC_NAME_MAX) limits. We are being conservative here and allocate
+            // buffer that is enough for PATH_MAX as the directory name. Still, this doesn't guarantee there won't be
+            // a buffer overrun. The readdir_r API is fundamentally flawed and we should avoid it as much as possible
+            // in favor of readdir.
+            extra_size = (sizeof(dirent) - sizeof(dirent().d_name)) + path_max() + 1u; // + 1 for "\0"
+        }
+    }
+#endif // defined(BOOST_FILESYSTEM_USE_READDIR_R)
+
+    boost::intrusive_ptr< detail::dir_itr_imp > pimpl(new (extra_size) detail::dir_itr_imp());
+    if (BOOST_UNLIKELY(!pimpl))
+        return make_error_code(system::errc::not_enough_memory);
+
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+    boost::scope::unique_fd fd;
+    if (params && params->dir_fd)
+    {
+        fd = std::move(params->dir_fd);
+    }
+    else
+    {
+        system::error_code ec;
+        fd = open_directory(dir, opts, ec);
+        if (BOOST_UNLIKELY(!!ec))
+            return ec;
+    }
+
+    pimpl->handle = ::fdopendir(fd.get());
+    if (BOOST_UNLIKELY(!pimpl->handle))
+    {
+        const int err = errno;
+        return system::error_code(err, system::system_category());
+    }
+
+    // At this point fd will be closed by closedir
+    fd.release();
+#else // defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+    pimpl->handle = ::opendir(dir.c_str());
+    if (BOOST_UNLIKELY(!pimpl->handle))
+    {
+        const int err = errno;
+        return system::error_code(err, system::system_category());
+    }
+#endif // defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+
+    // Force initial readdir call by the caller. This will initialize the actual first filename and statuses.
+    first_filename.assign(".");
+
+    imp.swap(pimpl);
+    return system::error_code();
+}
+
+BOOST_CONSTEXPR_OR_CONST err_t not_found_error_code = ENOENT;
+
+#else // BOOST_WINDOWS_API
+
+inline void set_file_statuses(DWORD attrs, const ULONG* reparse_point_tag, fs::path const& filename, fs::file_status& sf, fs::file_status& symlink_sf)
+{
+    if ((attrs & FILE_ATTRIBUTE_REPARSE_POINT) != 0u)
+    {
+        // Reparse points are complex, so don't try to resolve them here; instead just mark
+        // them as status_error which causes directory_entry caching to call status()
+        // and symlink_status() which do handle reparse points fully
+        if (reparse_point_tag)
+        {
+            // If we have a reparse point tag we can at least populate the symlink status,
+            // consistent with symlink_status() behavior
+            symlink_sf.type(is_reparse_point_tag_a_symlink(*reparse_point_tag) ? fs::symlink_file : fs::reparse_file);
+            symlink_sf.permissions(make_permissions(filename, attrs));
+        }
+        else
+        {
+            symlink_sf.type(fs::status_error);
+        }
+
+        sf.type(fs::status_error);
+    }
+    else
+    {
+        if ((attrs & FILE_ATTRIBUTE_DIRECTORY) != 0u)
+        {
+            sf.type(fs::directory_file);
+            symlink_sf.type(fs::directory_file);
+        }
+        else
+        {
+            sf.type(fs::regular_file);
+            symlink_sf.type(fs::regular_file);
+        }
+
+        sf.permissions(make_permissions(filename, attrs));
+        symlink_sf.permissions(sf.permissions());
+    }
+}
+
+//! FILE_ID_128 definition from Windows SDK
+struct file_id_128
+{
+    BYTE Identifier[16];
+};
+
+//! FILE_DIRECTORY_INFORMATION definition from Windows DDK. Used by NtQueryDirectoryFile, supported since Windows NT 4.0 (probably).
+struct file_directory_information
+{
+    ULONG NextEntryOffset;
+    ULONG FileIndex;
+    LARGE_INTEGER CreationTime;
+    LARGE_INTEGER LastAccessTime;
+    LARGE_INTEGER LastWriteTime;
+    LARGE_INTEGER ChangeTime;
+    LARGE_INTEGER EndOfFile;
+    LARGE_INTEGER AllocationSize;
+    ULONG FileAttributes;
+    ULONG FileNameLength;
+    WCHAR FileName[1];
+};
+
+//! FILE_ID_BOTH_DIR_INFO definition from Windows SDK. Basic support for directory iteration using GetFileInformationByHandleEx, supported since Windows Vista.
+struct file_id_both_dir_info
+{
+    DWORD NextEntryOffset;
+    DWORD FileIndex;
+    LARGE_INTEGER CreationTime;
+    LARGE_INTEGER LastAccessTime;
+    LARGE_INTEGER LastWriteTime;
+    LARGE_INTEGER ChangeTime;
+    LARGE_INTEGER EndOfFile;
+    LARGE_INTEGER AllocationSize;
+    DWORD FileAttributes;
+    DWORD FileNameLength;
+    DWORD EaSize;
+    CCHAR ShortNameLength;
+    WCHAR ShortName[12];
+    LARGE_INTEGER FileId;
+    WCHAR FileName[1];
+};
+
+//! FILE_FULL_DIR_INFO definition from Windows SDK. More lightweight than FILE_ID_BOTH_DIR_INFO, supported since Windows 8.
+struct file_full_dir_info
+{
+    ULONG NextEntryOffset;
+    ULONG FileIndex;
+    LARGE_INTEGER CreationTime;
+    LARGE_INTEGER LastAccessTime;
+    LARGE_INTEGER LastWriteTime;
+    LARGE_INTEGER ChangeTime;
+    LARGE_INTEGER EndOfFile;
+    LARGE_INTEGER AllocationSize;
+    ULONG FileAttributes;
+    ULONG FileNameLength;
+    ULONG EaSize;
+    WCHAR FileName[1];
+};
+
+//! FILE_ID_EXTD_DIR_INFO definition from Windows SDK. Provides reparse point tag, which saves us querying it with a few separate syscalls. Supported since Windows 8.
+struct file_id_extd_dir_info
+{
+    ULONG NextEntryOffset;
+    ULONG FileIndex;
+    LARGE_INTEGER CreationTime;
+    LARGE_INTEGER LastAccessTime;
+    LARGE_INTEGER LastWriteTime;
+    LARGE_INTEGER ChangeTime;
+    LARGE_INTEGER EndOfFile;
+    LARGE_INTEGER AllocationSize;
+    ULONG FileAttributes;
+    ULONG FileNameLength;
+    ULONG EaSize;
+    ULONG ReparsePointTag;
+    file_id_128 FileId;
+    WCHAR FileName[1];
+};
+
+//! Indicates format of the extra data in the directory iterator
+enum extra_data_format
+{
+    file_directory_information_format,
+    file_id_both_dir_info_format,
+    file_full_dir_info_format,
+    file_id_extd_dir_info_format
+};
+
+//! Indicates extra data format that should be used by directory iterator by default
+extra_data_format g_extra_data_format = file_directory_information_format;
+
+/*!
+ * \brief Extra buffer size for GetFileInformationByHandleEx-based or NtQueryDirectoryFile-based directory iterator.
+ *
+ * Must be large enough to accommodate at least one FILE_DIRECTORY_INFORMATION or *_DIR_INFO struct and one filename.
+ * NTFS, VFAT, exFAT and ReFS support filenames up to 255 UTF-16/UCS-2 characters. (For ReFS, there is no information
+ * on the on-disk format, and it is possible that it supports longer filenames, up to 32768 UTF-16/UCS-2 characters.)
+ * The buffer cannot be larger than 64k, otherwise up to Windows 8.1, NtQueryDirectoryFile and GetFileInformationByHandleEx
+ * fail with ERROR_INVALID_PARAMETER when trying to retrieve filenames from a network share.
+ */
+BOOST_CONSTEXPR_OR_CONST std::size_t dir_itr_extra_size = 65536u;
+
+inline system::error_code dir_itr_close(dir_itr_imp& imp) noexcept
+{
+    imp.extra_data_format = 0u;
+    imp.current_offset = 0u;
+
+    if (imp.handle != nullptr)
+    {
+        if (BOOST_LIKELY(imp.close_handle))
+            ::CloseHandle(imp.handle);
+        imp.handle = nullptr;
+    }
+
+    return error_code();
+}
+
+system::error_code dir_itr_increment(dir_itr_imp& imp, fs::path& filename, fs::file_status& sf, fs::file_status& symlink_sf)
+{
+    void* extra_data = get_dir_itr_imp_extra_data(&imp);
+    const void* current_data = static_cast< const unsigned char* >(extra_data) + imp.current_offset;
+    switch (imp.extra_data_format)
+    {
+    case file_id_extd_dir_info_format:
+        {
+            const file_id_extd_dir_info* data = static_cast< const file_id_extd_dir_info* >(current_data);
+            if (data->NextEntryOffset == 0u)
+            {
+                if (!filesystem::detail::atomic_load_relaxed(get_file_information_by_handle_ex_api)(imp.handle, file_id_extd_directory_info_class, extra_data, dir_itr_extra_size))
+                {
+                    DWORD error = ::GetLastError();
+
+                    dir_itr_close(imp);
+                    if (error == ERROR_NO_MORE_FILES)
+                        goto done;
+
+                    return system::error_code(error, system::system_category());
+                }
+
+                imp.current_offset = 0u;
+                data = static_cast< const file_id_extd_dir_info* >(extra_data);
+            }
+            else
+            {
+                imp.current_offset += data->NextEntryOffset;
+                data = reinterpret_cast< const file_id_extd_dir_info* >(static_cast< const unsigned char* >(current_data) + data->NextEntryOffset);
+            }
+
+            filename.assign(data->FileName, data->FileName + data->FileNameLength / sizeof(WCHAR));
+            set_file_statuses(data->FileAttributes, &data->ReparsePointTag, filename, sf, symlink_sf);
+        }
+        break;
+
+    case file_full_dir_info_format:
+        {
+            const file_full_dir_info* data = static_cast< const file_full_dir_info* >(current_data);
+            if (data->NextEntryOffset == 0u)
+            {
+                if (!filesystem::detail::atomic_load_relaxed(get_file_information_by_handle_ex_api)(imp.handle, file_full_directory_info_class, extra_data, dir_itr_extra_size))
+                {
+                    DWORD error = ::GetLastError();
+
+                    dir_itr_close(imp);
+                    if (error == ERROR_NO_MORE_FILES)
+                        goto done;
+
+                    return system::error_code(error, system::system_category());
+                }
+
+                imp.current_offset = 0u;
+                data = static_cast< const file_full_dir_info* >(extra_data);
+            }
+            else
+            {
+                imp.current_offset += data->NextEntryOffset;
+                data = reinterpret_cast< const file_full_dir_info* >(static_cast< const unsigned char* >(current_data) + data->NextEntryOffset);
+            }
+
+            filename.assign(data->FileName, data->FileName + data->FileNameLength / sizeof(WCHAR));
+            set_file_statuses(data->FileAttributes, nullptr, filename, sf, symlink_sf);
+        }
+        break;
+
+    case file_id_both_dir_info_format:
+        {
+            const file_id_both_dir_info* data = static_cast< const file_id_both_dir_info* >(current_data);
+            if (data->NextEntryOffset == 0u)
+            {
+                if (!filesystem::detail::atomic_load_relaxed(get_file_information_by_handle_ex_api)(imp.handle, file_id_both_directory_info_class, extra_data, dir_itr_extra_size))
+                {
+                    DWORD error = ::GetLastError();
+
+                    dir_itr_close(imp);
+                    if (error == ERROR_NO_MORE_FILES)
+                        goto done;
+
+                    return system::error_code(error, system::system_category());
+                }
+
+                imp.current_offset = 0u;
+                data = static_cast< const file_id_both_dir_info* >(extra_data);
+            }
+            else
+            {
+                imp.current_offset += data->NextEntryOffset;
+                data = reinterpret_cast< const file_id_both_dir_info* >(static_cast< const unsigned char* >(current_data) + data->NextEntryOffset);
+            }
+
+            filename.assign(data->FileName, data->FileName + data->FileNameLength / sizeof(WCHAR));
+            set_file_statuses(data->FileAttributes, nullptr, filename, sf, symlink_sf);
+        }
+        break;
+
+    default:
+        {
+            const file_directory_information* data = static_cast< const file_directory_information* >(current_data);
+            if (data->NextEntryOffset == 0u)
+            {
+                io_status_block iosb;
+                boost::winapi::NTSTATUS_ status = filesystem::detail::atomic_load_relaxed(nt_query_directory_file_api)
+                (
+                    imp.handle,
+                    nullptr, // Event
+                    nullptr, // ApcRoutine
+                    nullptr, // ApcContext
+                    &iosb,
+                    extra_data,
+                    dir_itr_extra_size,
+                    file_directory_information_class,
+                    FALSE, // ReturnSingleEntry
+                    nullptr, // FileName
+                    FALSE // RestartScan
+                );
+
+                if (!NT_SUCCESS(status))
+                {
+                    dir_itr_close(imp);
+                    if (status == STATUS_NO_MORE_FILES)
+                        goto done;
+
+                    return system::error_code(translate_ntstatus(status), system::system_category());
+                }
+
+                imp.current_offset = 0u;
+                data = static_cast< const file_directory_information* >(extra_data);
+            }
+            else
+            {
+                imp.current_offset += data->NextEntryOffset;
+                data = reinterpret_cast< const file_directory_information* >(static_cast< const unsigned char* >(current_data) + data->NextEntryOffset);
+            }
+
+            filename.assign(data->FileName, data->FileName + data->FileNameLength / sizeof(WCHAR));
+            set_file_statuses(data->FileAttributes, nullptr, filename, sf, symlink_sf);
+        }
+        break;
+    }
+
+done:
+    return system::error_code();
+}
+
+//! Returns \c true if the error code indicates that the OS or the filesystem does not support a particular directory info class
+inline bool is_dir_info_class_not_supported(DWORD error)
+{
+    // Some mounted filesystems may not support FILE_ID_128 identifiers, which will cause
+    // GetFileInformationByHandleEx(FileIdExtdDirectoryRestartInfo) return ERROR_INVALID_PARAMETER,
+    // even though in general the operation is supported by the kernel. SMBv1 returns a special error
+    // code ERROR_INVALID_LEVEL in this case.
+    // Some other filesystems also don't implement other info classes and return ERROR_INVALID_PARAMETER
+    // (e.g. see https://github.com/boostorg/filesystem/issues/266), ERROR_GEN_FAILURE, ERROR_INVALID_FUNCTION
+    // or ERROR_INTERNAL_ERROR (https://github.com/boostorg/filesystem/issues/286). Treat these error codes
+    // as "non-permanent", even though ERROR_INVALID_PARAMETER is also returned if GetFileInformationByHandleEx
+    // in general does not support a certain info class. Worst case, we will make extra syscalls on directory
+    // iterator construction.
+    // Also note that Wine returns ERROR_CALL_NOT_IMPLEMENTED for unimplemented info classes, and
+    // up until 7.21 it didn't implement FileIdExtdDirectoryRestartInfo and FileFullDirectoryRestartInfo.
+    // (https://bugs.winehq.org/show_bug.cgi?id=53590)
+    return error == ERROR_NOT_SUPPORTED || error == ERROR_INVALID_PARAMETER ||
+        error == ERROR_INVALID_LEVEL || error == ERROR_CALL_NOT_IMPLEMENTED ||
+        error == ERROR_GEN_FAILURE || error == ERROR_INVALID_FUNCTION ||
+        error == ERROR_INTERNAL_ERROR;
+}
+
+system::error_code dir_itr_create(boost::intrusive_ptr< detail::dir_itr_imp >& imp, fs::path const& dir, directory_options opts, directory_iterator_params* params, fs::path& first_filename, fs::file_status& sf, fs::file_status& symlink_sf)
+{
+    boost::intrusive_ptr< detail::dir_itr_imp > pimpl(new (dir_itr_extra_size) detail::dir_itr_imp());
+    if (BOOST_UNLIKELY(!pimpl))
+        return make_error_code(system::errc::not_enough_memory);
+
+    GetFileInformationByHandleEx_t* get_file_information_by_handle_ex = filesystem::detail::atomic_load_relaxed(get_file_information_by_handle_ex_api);
+
+    unique_handle h;
+    HANDLE iterator_handle;
+    bool close_handle = true;
+    if (params != nullptr && params->dir_handle != INVALID_HANDLE_VALUE)
+    {
+        // Operate on externally provided handle, which must be a directory handle
+        iterator_handle = params->dir_handle;
+        close_handle = params->close_handle;
+    }
+    else
+    {
+        DWORD flags = FILE_FLAG_BACKUP_SEMANTICS;
+        if ((opts & directory_options::_detail_no_follow) != directory_options::none)
+            flags |= FILE_FLAG_OPEN_REPARSE_POINT;
+
+        h = create_file_handle(dir, FILE_LIST_DIRECTORY, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, nullptr, OPEN_EXISTING, flags);
+        if (BOOST_UNLIKELY(!h))
+        {
+        return_last_error:
+            DWORD error = ::GetLastError();
+            return system::error_code(error, system::system_category());
+        }
+
+        iterator_handle = h.get();
+
+        if (BOOST_LIKELY(get_file_information_by_handle_ex != nullptr))
+        {
+            file_attribute_tag_info info;
+            BOOL res = get_file_information_by_handle_ex(iterator_handle, file_attribute_tag_info_class, &info, sizeof(info));
+            if (BOOST_UNLIKELY(!res))
+            {
+                // On FAT/exFAT filesystems requesting FILE_ATTRIBUTE_TAG_INFO returns ERROR_INVALID_PARAMETER. See the comment in symlink_status.
+                DWORD error = ::GetLastError();
+                if (error == ERROR_INVALID_PARAMETER || error == ERROR_NOT_SUPPORTED)
+                    goto use_get_file_information_by_handle;
+
+                return system::error_code(error, system::system_category());
+            }
+
+            if (BOOST_UNLIKELY((info.FileAttributes & FILE_ATTRIBUTE_DIRECTORY) == 0u))
+                return make_error_code(system::errc::not_a_directory);
+
+            if ((opts & directory_options::_detail_no_follow) != directory_options::none)
+            {
+                if ((info.FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) != 0u && is_reparse_point_tag_a_symlink(info.ReparseTag))
+                    return make_error_code(system::errc::too_many_symbolic_link_levels);
+            }
+        }
+        else
+        {
+        use_get_file_information_by_handle:
+            BY_HANDLE_FILE_INFORMATION info;
+            BOOL res = ::GetFileInformationByHandle(iterator_handle, &info);
+            if (BOOST_UNLIKELY(!res))
+                goto return_last_error;
+
+            if (BOOST_UNLIKELY((info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == 0u))
+                return make_error_code(system::errc::not_a_directory);
+
+            if ((opts & directory_options::_detail_no_follow) != directory_options::none && (info.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) != 0u)
+            {
+                error_code ec;
+                const ULONG reparse_point_tag = detail::get_reparse_point_tag_ioctl(iterator_handle, dir, &ec);
+                if (BOOST_UNLIKELY(!!ec))
+                    return ec;
+
+                if (detail::is_reparse_point_tag_a_symlink(reparse_point_tag))
+                    return make_error_code(system::errc::too_many_symbolic_link_levels);
+            }
+        }
+    }
+
+    void* extra_data = get_dir_itr_imp_extra_data(pimpl.get());
+    switch (filesystem::detail::atomic_load_relaxed(g_extra_data_format))
+    {
+    case file_id_extd_dir_info_format:
+        {
+            if (!get_file_information_by_handle_ex(iterator_handle, file_id_extd_directory_restart_info_class, extra_data, dir_itr_extra_size))
+            {
+                DWORD error = ::GetLastError();
+
+                if (is_dir_info_class_not_supported(error))
+                {
+                    // Fall back to file_full_dir_info_format.
+                    if (error == ERROR_NOT_SUPPORTED || error == ERROR_CALL_NOT_IMPLEMENTED)
+                        filesystem::detail::atomic_store_relaxed(g_extra_data_format, file_full_dir_info_format);
+                    goto fallback_to_file_full_dir_info_format;
+                }
+
+                if (error == ERROR_NO_MORE_FILES || error == ERROR_FILE_NOT_FOUND)
+                    goto done;
+
+                return system::error_code(error, system::system_category());
+            }
+
+            pimpl->extra_data_format = file_id_extd_dir_info_format;
+
+            const file_id_extd_dir_info* data = static_cast< const file_id_extd_dir_info* >(extra_data);
+            first_filename.assign(data->FileName, data->FileName + data->FileNameLength / sizeof(WCHAR));
+
+            set_file_statuses(data->FileAttributes, &data->ReparsePointTag, first_filename, sf, symlink_sf);
+        }
+        break;
+
+    case file_full_dir_info_format:
+    fallback_to_file_full_dir_info_format:
+        {
+            if (!get_file_information_by_handle_ex(iterator_handle, file_full_directory_restart_info_class, extra_data, dir_itr_extra_size))
+            {
+                DWORD error = ::GetLastError();
+
+                if (is_dir_info_class_not_supported(error))
+                {
+                    // Fall back to file_id_both_dir_info
+                    if (error == ERROR_NOT_SUPPORTED || error == ERROR_CALL_NOT_IMPLEMENTED)
+                        filesystem::detail::atomic_store_relaxed(g_extra_data_format, file_id_both_dir_info_format);
+                    goto fallback_to_file_id_both_dir_info_format;
+                }
+
+                if (error == ERROR_NO_MORE_FILES || error == ERROR_FILE_NOT_FOUND)
+                    goto done;
+
+                return system::error_code(error, system::system_category());
+            }
+
+            pimpl->extra_data_format = file_full_dir_info_format;
+
+            const file_full_dir_info* data = static_cast< const file_full_dir_info* >(extra_data);
+            first_filename.assign(data->FileName, data->FileName + data->FileNameLength / sizeof(WCHAR));
+
+            set_file_statuses(data->FileAttributes, nullptr, first_filename, sf, symlink_sf);
+        }
+        break;
+
+    case file_id_both_dir_info_format:
+    fallback_to_file_id_both_dir_info_format:
+        {
+            if (!get_file_information_by_handle_ex(iterator_handle, file_id_both_directory_restart_info_class, extra_data, dir_itr_extra_size))
+            {
+                DWORD error = ::GetLastError();
+
+                if (is_dir_info_class_not_supported(error))
+                {
+                    // Fall back to file_directory_information
+                    if (error == ERROR_NOT_SUPPORTED || error == ERROR_CALL_NOT_IMPLEMENTED)
+                        filesystem::detail::atomic_store_relaxed(g_extra_data_format, file_directory_information_format);
+                    goto fallback_to_file_directory_information_format;
+                }
+
+                if (error == ERROR_NO_MORE_FILES || error == ERROR_FILE_NOT_FOUND)
+                    goto done;
+
+                return system::error_code(error, system::system_category());
+            }
+
+            pimpl->extra_data_format = file_id_both_dir_info_format;
+
+            const file_id_both_dir_info* data = static_cast< const file_id_both_dir_info* >(extra_data);
+            first_filename.assign(data->FileName, data->FileName + data->FileNameLength / sizeof(WCHAR));
+
+            set_file_statuses(data->FileAttributes, nullptr, first_filename, sf, symlink_sf);
+        }
+        break;
+
+    default:
+    fallback_to_file_directory_information_format:
+        {
+            NtQueryDirectoryFile_t* nt_query_directory_file = filesystem::detail::atomic_load_relaxed(boost::filesystem::detail::nt_query_directory_file_api);
+            if (BOOST_UNLIKELY(!nt_query_directory_file))
+                return error_code(ERROR_NOT_SUPPORTED, system_category());
+
+            io_status_block iosb;
+            boost::winapi::NTSTATUS_ status = nt_query_directory_file
+            (
+                iterator_handle,
+                nullptr, // Event
+                nullptr, // ApcRoutine
+                nullptr, // ApcContext
+                &iosb,
+                extra_data,
+                dir_itr_extra_size,
+                file_directory_information_class,
+                FALSE, // ReturnSingleEntry
+                nullptr, // FileName
+                TRUE // RestartScan
+            );
+
+            if (!NT_SUCCESS(status))
+            {
+                // Note: an empty root directory has no "." or ".." entries, so this
+                // causes a ERROR_FILE_NOT_FOUND error returned from FindFirstFileW
+                // (which is presumably equivalent to STATUS_NO_SUCH_FILE) which we
+                // do not consider an error. It is treated as eof instead.
+                if (status == STATUS_NO_MORE_FILES || status == STATUS_NO_SUCH_FILE)
+                    goto done;
+
+                return error_code(translate_ntstatus(status), system_category());
+            }
+
+            pimpl->extra_data_format = file_directory_information_format;
+
+            const file_directory_information* data = static_cast< const file_directory_information* >(extra_data);
+            first_filename.assign(data->FileName, data->FileName + data->FileNameLength / sizeof(WCHAR));
+
+            set_file_statuses(data->FileAttributes, nullptr, first_filename, sf, symlink_sf);
+        }
+        break;
+    }
+
+    pimpl->handle = iterator_handle;
+    h.release();
+    pimpl->close_handle = close_handle;
+
+done:
+    imp.swap(pimpl);
+    return system::error_code();
+}
+
+BOOST_CONSTEXPR_OR_CONST err_t not_found_error_code = ERROR_PATH_NOT_FOUND;
+
+#endif // BOOST_WINDOWS_API
+
+} // namespace
+
+#if defined(BOOST_POSIX_API)
+
+//! Tests if the directory is empty
+bool is_empty_directory(boost::scope::unique_fd&& fd, path const& p, error_code* ec)
+{
+#if !defined(BOOST_FILESYSTEM_USE_READDIR_R)
+    // Use a more optimal implementation without the overhead of constructing the iterator state
+
+    struct closedir_deleter
+    {
+        using result_type = void;
+        result_type operator() (DIR* dir) const noexcept
+        {
+            ::closedir(dir);
+        }
+    };
+
+    int err;
+
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+    std::unique_ptr< DIR, closedir_deleter > dir(::fdopendir(fd.get()));
+    if (BOOST_UNLIKELY(!dir))
+    {
+        err = errno;
+    fail:
+        emit_error(err, p, ec, "boost::filesystem::is_empty");
+        return false;
+    }
+
+    // At this point fd will be closed by closedir
+    fd.release();
+#else // defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+    std::unique_ptr< DIR, closedir_deleter > dir(::opendir(p.c_str()));
+    if (BOOST_UNLIKELY(!dir))
+    {
+        err = errno;
+    fail:
+        emit_error(err, p, ec, "boost::filesystem::is_empty");
+        return false;
+    }
+#endif // defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+
+    while (true)
+    {
+        errno = 0;
+        struct dirent* const ent = ::readdir(dir.get());
+        if (!ent)
+        {
+            err = errno;
+            if (err != 0)
+                goto fail;
+
+            return true;
+        }
+
+        // Skip dot and dot-dot entries
+        if (!(ent->d_name[0] == path::dot
+            && (ent->d_name[1] == static_cast< path::string_type::value_type >('\0') ||
+                (ent->d_name[1] == path::dot && ent->d_name[2] == static_cast< path::string_type::value_type >('\0')))))
+        {
+            return false;
+        }
+    }
+
+#else // !defined(BOOST_FILESYSTEM_USE_READDIR_R)
+
+    filesystem::directory_iterator itr;
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+    filesystem::detail::directory_iterator_params params{ std::move(fd) };
+    filesystem::detail::directory_iterator_construct(itr, p, directory_options::none, &params, ec);
+#else
+    filesystem::detail::directory_iterator_construct(itr, p, directory_options::none, nullptr, ec);
+#endif
+    return itr == filesystem::directory_iterator();
+
+#endif // !defined(BOOST_FILESYSTEM_USE_READDIR_R)
+}
+
+#else // BOOST_WINDOWS_API
+
+//! Tests if the directory is empty
+bool is_empty_directory(unique_handle&& h, path const& p, error_code* ec)
+{
+    filesystem::directory_iterator itr;
+    filesystem::detail::directory_iterator_params params{ h.get(), false };
+    filesystem::detail::directory_iterator_construct(itr, p, directory_options::none, &params, ec);
+    return itr == filesystem::directory_iterator();
+}
+
+//! Initializes directory iterator implementation
+void init_directory_iterator_impl() noexcept
+{
+    if (filesystem::detail::atomic_load_relaxed(get_file_information_by_handle_ex_api) != nullptr)
+    {
+        // Enable the latest format we support. It will get downgraded, if needed, as we attempt
+        // to create the directory iterator the first time.
+        filesystem::detail::atomic_store_relaxed(g_extra_data_format, file_id_extd_dir_info_format);
+    }
+}
+
+#endif // defined(BOOST_WINDOWS_API)
+
+BOOST_FILESYSTEM_DECL
+dir_itr_imp::~dir_itr_imp() noexcept
+{
+    dir_itr_close(*this);
+}
+
+BOOST_FILESYSTEM_DECL
+void directory_iterator_construct(directory_iterator& it, path const& p, directory_options opts, directory_iterator_params* params, system::error_code* ec)
+{
+    // At most one of the two options may be specified, and follow_directory_symlink is ignored for directory_iterator.
+    BOOST_ASSERT((opts & (directory_options::follow_directory_symlink | directory_options::_detail_no_follow)) != (directory_options::follow_directory_symlink | directory_options::_detail_no_follow));
+
+    if (BOOST_UNLIKELY(p.empty()))
+    {
+        emit_error(not_found_error_code, p, ec, "boost::filesystem::directory_iterator::construct");
+        return;
+    }
+
+    if (ec)
+        ec->clear();
+
+    try
+    {
+        boost::intrusive_ptr< detail::dir_itr_imp > imp;
+        path filename;
+        file_status file_stat, symlink_file_stat;
+        system::error_code result = dir_itr_create(imp, p, opts, params, filename, file_stat, symlink_file_stat);
+
+        while (true)
+        {
+            if (result)
+            {
+                if (result != make_error_condition(system::errc::permission_denied) ||
+                    (opts & directory_options::skip_permission_denied) == directory_options::none)
+                {
+                    if (!ec)
+                        BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::directory_iterator::construct", p, result));
+                    *ec = result;
+                }
+
+                return;
+            }
+
+            if (imp->handle == nullptr) // eof, make end
+                return;
+
+            // Not eof
+            const path::string_type::value_type* filename_str = filename.c_str();
+            if (!(filename_str[0] == path::dot // dot or dot-dot
+                && (filename_str[1] == static_cast< path::string_type::value_type >('\0') ||
+                    (filename_str[1] == path::dot && filename_str[2] == static_cast< path::string_type::value_type >('\0')))))
+            {
+                path full_path(p);
+                path_algorithms::append_v4(full_path, filename);
+                imp->dir_entry.assign_with_status
+                (
+                    static_cast< path&& >(full_path),
+                    file_stat,
+                    symlink_file_stat
+                );
+                it.m_imp.swap(imp);
+                return;
+            }
+
+            // If dot or dot-dot name produced by the underlying API, skip it until the first actual file
+            result = dir_itr_increment(*imp, filename, file_stat, symlink_file_stat);
+        }
+    }
+    catch (std::bad_alloc&)
+    {
+        if (!ec)
+            throw;
+
+        *ec = make_error_code(system::errc::not_enough_memory);
+        it.m_imp.reset();
+    }
+}
+
+BOOST_FILESYSTEM_DECL
+void directory_iterator_increment(directory_iterator& it, system::error_code* ec)
+{
+    BOOST_ASSERT_MSG(!it.is_end(), "attempt to increment end iterator");
+
+    if (ec)
+        ec->clear();
+
+    try
+    {
+        path filename;
+        file_status file_stat, symlink_file_stat;
+        system::error_code increment_ec;
+
+        while (true)
+        {
+            increment_ec = dir_itr_increment(*it.m_imp, filename, file_stat, symlink_file_stat);
+
+            if (BOOST_UNLIKELY(!!increment_ec)) // happens if filesystem is corrupt, such as on a damaged optical disc
+            {
+                boost::intrusive_ptr< detail::dir_itr_imp > imp;
+                imp.swap(it.m_imp);
+                path error_path(imp->dir_entry.path().parent_path()); // fix ticket #5900
+                if (!ec)
+                    BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::directory_iterator::operator++", error_path, increment_ec));
+
+                *ec = increment_ec;
+                return;
+            }
+
+            if (it.m_imp->handle == nullptr) // eof, make end
+            {
+                it.m_imp.reset();
+                return;
+            }
+
+            const path::string_type::value_type* filename_str = filename.c_str();
+            if (!(filename_str[0] == path::dot // !(dot or dot-dot)
+                  && (filename_str[1] == static_cast< path::string_type::value_type >('\0') ||
+                      (filename_str[1] == path::dot && filename_str[2] == static_cast< path::string_type::value_type >('\0')))))
+            {
+                it.m_imp->dir_entry.replace_filename_with_status(filename, file_stat, symlink_file_stat);
+                return;
+            }
+        }
+    }
+    catch (std::bad_alloc&)
+    {
+        if (!ec)
+            throw;
+
+        it.m_imp.reset();
+        *ec = make_error_code(system::errc::not_enough_memory);
+    }
+}
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//                           recursive_directory_iterator                               //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL
+void recursive_directory_iterator_construct(recursive_directory_iterator& it, path const& dir_path, directory_options opts, system::error_code* ec)
+{
+    // At most one of the two options may be specified
+    BOOST_ASSERT((opts & (directory_options::follow_directory_symlink | directory_options::_detail_no_follow)) != (directory_options::follow_directory_symlink | directory_options::_detail_no_follow));
+
+    if (ec)
+        ec->clear();
+
+    directory_iterator dir_it;
+    detail::directory_iterator_construct(dir_it, dir_path, opts, nullptr, ec);
+    if ((ec && *ec) || dir_it == directory_iterator())
+        return;
+
+    boost::intrusive_ptr< detail::recur_dir_itr_imp > imp;
+    if (!ec)
+    {
+        imp = new detail::recur_dir_itr_imp(opts);
+    }
+    else
+    {
+        imp = new (std::nothrow) detail::recur_dir_itr_imp(opts);
+        if (BOOST_UNLIKELY(!imp))
+        {
+            *ec = make_error_code(system::errc::not_enough_memory);
+            return;
+        }
+    }
+
+    try
+    {
+        imp->m_stack.push_back(std::move(dir_it));
+        it.m_imp.swap(imp);
+    }
+    catch (std::bad_alloc&)
+    {
+        if (ec)
+        {
+            *ec = make_error_code(system::errc::not_enough_memory);
+            return;
+        }
+
+        throw;
+    }
+}
+
+namespace {
+
+void recursive_directory_iterator_pop_on_error(detail::recur_dir_itr_imp* imp)
+{
+    imp->m_stack.pop_back();
+
+    while (!imp->m_stack.empty())
+    {
+        directory_iterator& dir_it = imp->m_stack.back();
+        system::error_code increment_ec;
+        detail::directory_iterator_increment(dir_it, &increment_ec);
+        if (!increment_ec && dir_it != directory_iterator())
+            break;
+
+        imp->m_stack.pop_back();
+    }
+}
+
+} // namespace
+
+BOOST_FILESYSTEM_DECL
+void recursive_directory_iterator_pop(recursive_directory_iterator& it, system::error_code* ec)
+{
+    BOOST_ASSERT_MSG(!it.is_end(), "pop() on end recursive_directory_iterator");
+    detail::recur_dir_itr_imp* const imp = it.m_imp.get();
+
+    if (ec)
+        ec->clear();
+
+    imp->m_stack.pop_back();
+
+    while (true)
+    {
+        if (imp->m_stack.empty())
+        {
+            it.m_imp.reset(); // done, so make end iterator
+            break;
+        }
+
+        directory_iterator& dir_it = imp->m_stack.back();
+        system::error_code increment_ec;
+        detail::directory_iterator_increment(dir_it, &increment_ec);
+        if (BOOST_UNLIKELY(!!increment_ec))
+        {
+            if ((imp->m_options & directory_options::pop_on_error) == directory_options::none)
+            {
+                // Make an end iterator on errors
+                it.m_imp.reset();
+            }
+            else
+            {
+                recursive_directory_iterator_pop_on_error(imp);
+
+                if (imp->m_stack.empty())
+                    it.m_imp.reset(); // done, so make end iterator
+            }
+
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::recursive_directory_iterator::pop", increment_ec));
+
+            *ec = increment_ec;
+            return;
+        }
+
+        if (dir_it != directory_iterator())
+            break;
+
+        imp->m_stack.pop_back();
+    }
+}
+
+BOOST_FILESYSTEM_DECL
+void recursive_directory_iterator_increment(recursive_directory_iterator& it, system::error_code* ec)
+{
+    enum push_directory_result : unsigned int
+    {
+        directory_not_pushed = 0u,
+        directory_pushed = 1u,
+        keep_depth = 1u << 1u
+    };
+
+    struct local
+    {
+        //! Attempts to descend into a directory
+        static push_directory_result push_directory(detail::recur_dir_itr_imp* imp, system::error_code& ec)
+        {
+            push_directory_result result = directory_not_pushed;
+            try
+            {
+                //  Discover if the iterator is for a directory that needs to be recursed into,
+                //  taking symlinks and options into account.
+
+                if ((imp->m_options & directory_options::_detail_no_push) != directory_options::none)
+                {
+                    imp->m_options &= ~directory_options::_detail_no_push;
+                    return result;
+                }
+
+                file_type symlink_ft = status_error;
+
+#if defined(BOOST_POSIX_API) && defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+                int parentdir_fd = -1;
+                path dir_it_filename;
+#elif defined(BOOST_WINDOWS_API)
+                unique_handle direntry_handle;
+#endif
+
+                // If we are not recursing into symlinks, we are going to have to know if the
+                // stack top is a symlink, so get symlink_status and verify no error occurred.
+                if ((imp->m_options & directory_options::follow_directory_symlink) == directory_options::none ||
+                    (imp->m_options & directory_options::skip_dangling_symlinks) != directory_options::none)
+                {
+#if defined(BOOST_POSIX_API) && defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+                    directory_iterator const& dir_it = imp->m_stack.back();
+                    if (filesystem::type_present(dir_it->m_symlink_status))
+                    {
+                        symlink_ft = dir_it->m_symlink_status.type();
+                    }
+                    else
+                    {
+                        parentdir_fd = dir_itr_fd(*dir_it.m_imp, ec);
+                        if (ec)
+                            return result;
+
+                        dir_it_filename = detail::path_algorithms::filename_v4(dir_it->path());
+
+                        symlink_ft = detail::symlink_status_impl(dir_it_filename, &ec, parentdir_fd).type();
+                        if (ec)
+                            return result;
+                    }
+#elif defined(BOOST_WINDOWS_API)
+                    directory_iterator const& dir_it = imp->m_stack.back();
+                    if (filesystem::type_present(dir_it->m_symlink_status))
+                    {
+                        symlink_ft = dir_it->m_symlink_status.type();
+                    }
+                    else
+                    {
+                        boost::winapi::NTSTATUS_ status = nt_create_file_handle_at
+                        (
+                            direntry_handle,
+                            static_cast< HANDLE >(dir_it.m_imp->handle),
+                            detail::path_algorithms::filename_v4(dir_it->path()),
+                            0u, // FileAttributes
+                            FILE_LIST_DIRECTORY | FILE_READ_ATTRIBUTES | FILE_READ_EA | SYNCHRONIZE,
+                            FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                            FILE_OPEN,
+                            FILE_SYNCHRONOUS_IO_NONALERT | FILE_OPEN_FOR_BACKUP_INTENT | FILE_OPEN_REPARSE_POINT
+                        );
+
+                        if (NT_SUCCESS(status))
+                        {
+                            symlink_ft = detail::status_by_handle(direntry_handle.get(), dir_it->path(), &ec).type();
+                        }
+                        else if (status == STATUS_NOT_IMPLEMENTED)
+                        {
+                            symlink_ft = dir_it->symlink_file_type(ec);
+                        }
+                        else
+                        {
+                            if (!not_found_ntstatus(status))
+                                ec.assign(translate_ntstatus(status), system::system_category());
+
+                            return result;
+                        }
+
+                        if (ec)
+                            return result;
+                    }
+#else
+                    symlink_ft = imp->m_stack.back()->symlink_file_type(ec);
+                    if (ec)
+                        return result;
+#endif
+                }
+
+                // Logic for following predicate was contributed by Daniel Aarno to handle cyclic
+                // symlinks correctly and efficiently, fixing ticket #5652.
+                //   if (((m_options & directory_options::follow_directory_symlink) == directory_options::follow_directory_symlink
+                //         || !is_symlink(m_stack.back()->symlink_status()))
+                //       && is_directory(m_stack.back()->status())) ...
+                // The predicate code has since been rewritten to pass error_code arguments,
+                // per ticket #5653.
+
+                if ((imp->m_options & directory_options::follow_directory_symlink) != directory_options::none || symlink_ft != symlink_file)
+                {
+                    directory_iterator const& dir_it = imp->m_stack.back();
+
+                    // Don't query the file type from the filesystem yet, if not known. We will use dir_it for that below.
+                    file_type ft = dir_it->m_status.type();
+                    if (ft != status_error && ft != directory_file)
+                        return result;
+
+#if defined(BOOST_POSIX_API) && defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+                    if (parentdir_fd < 0)
+                    {
+                        parentdir_fd = dir_itr_fd(*dir_it.m_imp, ec);
+                        if (ec)
+                            return result;
+
+                        dir_it_filename = detail::path_algorithms::filename_v4(dir_it->path());
+                    }
+
+                    // Try to open the file as a directory right away. This effectively tests whether the file is a directory, and, if it is, opens the directory in one system call.
+                    detail::directory_iterator_params params{ detail::openat_directory(parentdir_fd, dir_it_filename, imp->m_options, ec) };
+                    if (!!ec)
+                    {
+                        if
+                        (
+                            // Skip non-directory files
+                            ec == system::error_code(ENOTDIR, system::system_category()) ||
+                            (
+                                // Skip dangling symlink, if requested by options
+                                ec == system::error_code(ENOENT, system::system_category()) && symlink_ft == symlink_file &&
+                                (imp->m_options & (directory_options::follow_directory_symlink | directory_options::skip_dangling_symlinks)) == (directory_options::follow_directory_symlink | directory_options::skip_dangling_symlinks)
+                            )
+                        )
+                        {
+                            ec.clear();
+                        }
+
+                        return result;
+                    }
+#else // defined(BOOST_POSIX_API) && defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+#if defined(BOOST_WINDOWS_API)
+                    if (!!direntry_handle && symlink_ft == symlink_file)
+                    {
+                        // Close the symlink to reopen the target file below
+                        direntry_handle.reset();
+                    }
+
+                    if (!direntry_handle)
+                    {
+                        boost::winapi::NTSTATUS_ status = nt_create_file_handle_at
+                        (
+                            direntry_handle,
+                            static_cast< HANDLE >(dir_it.m_imp->handle),
+                            detail::path_algorithms::filename_v4(dir_it->path()),
+                            0u, // FileAttributes
+                            FILE_LIST_DIRECTORY | FILE_READ_ATTRIBUTES | FILE_READ_EA | SYNCHRONIZE,
+                            FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                            FILE_OPEN,
+                            FILE_SYNCHRONOUS_IO_NONALERT | FILE_OPEN_FOR_BACKUP_INTENT
+                        );
+
+                        if (NT_SUCCESS(status))
+                        {
+                            goto get_file_type_by_handle;
+                        }
+                        else if (status == STATUS_NOT_IMPLEMENTED)
+                        {
+                            ft = dir_it->file_type(ec);
+                        }
+                        else
+                        {
+                            ec.assign(translate_ntstatus(status), system::system_category());
+                        }
+                    }
+                    else
+                    {
+                    get_file_type_by_handle:
+                        ft = detail::status_by_handle(direntry_handle.get(), dir_it->path(), &ec).type();
+                    }
+#else // defined(BOOST_WINDOWS_API)
+                    if (ft == status_error)
+                        ft = dir_it->file_type(ec);
+#endif // defined(BOOST_WINDOWS_API)
+
+                    if (BOOST_UNLIKELY(!!ec))
+                    {
+                        if (ec == make_error_condition(system::errc::no_such_file_or_directory) && symlink_ft == symlink_file &&
+                            (imp->m_options & (directory_options::follow_directory_symlink | directory_options::skip_dangling_symlinks)) == (directory_options::follow_directory_symlink | directory_options::skip_dangling_symlinks))
+                        {
+                            // Skip dangling symlink and continue iteration on the current depth level
+                            ec.clear();
+                        }
+
+                        return result;
+                    }
+
+                    if (ft != directory_file)
+                        return result;
+#endif // defined(BOOST_POSIX_API) && defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+
+                    if (BOOST_UNLIKELY((imp->m_stack.size() - 1u) >= static_cast< std::size_t >((std::numeric_limits< int >::max)())))
+                    {
+                        // We cannot let depth to overflow
+                        ec = make_error_code(system::errc::value_too_large);
+                        // When depth overflow happens, avoid popping the current directory iterator
+                        // and attempt to continue iteration on the current depth.
+                        result = keep_depth;
+                        return result;
+                    }
+
+#if defined(BOOST_POSIX_API) && defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+                    directory_iterator next;
+                    detail::directory_iterator_construct(next, dir_it->path(), imp->m_options, &params, &ec);
+#elif defined(BOOST_WINDOWS_API)
+                    detail::directory_iterator_params params;
+                    params.dir_handle = direntry_handle.get();
+                    params.close_handle = true;
+                    directory_iterator next;
+                    detail::directory_iterator_construct(next, dir_it->path(), imp->m_options, &params, &ec);
+#else
+                    directory_iterator next(dir_it->path(), imp->m_options, ec);
+#endif
+                    if (BOOST_LIKELY(!ec))
+                    {
+#if defined(BOOST_WINDOWS_API)
+                        direntry_handle.release();
+#endif
+                        if (!next.is_end())
+                        {
+                            imp->m_stack.push_back(std::move(next)); // may throw
+                            return directory_pushed;
+                        }
+                    }
+                }
+            }
+            catch (std::bad_alloc&)
+            {
+                ec = make_error_code(system::errc::not_enough_memory);
+            }
+
+            return result;
+        }
+    };
+
+    BOOST_ASSERT_MSG(!it.is_end(), "increment() on end recursive_directory_iterator");
+    detail::recur_dir_itr_imp* const imp = it.m_imp.get();
+
+    if (ec)
+        ec->clear();
+
+    system::error_code local_ec;
+
+    //  if various conditions are met, push a directory_iterator into the iterator stack
+    push_directory_result push_result = local::push_directory(imp, local_ec);
+    if (push_result == directory_pushed)
+        return;
+
+    // report errors if any
+    if (BOOST_UNLIKELY(!!local_ec))
+    {
+    on_error:
+        if ((imp->m_options & directory_options::pop_on_error) == directory_options::none)
+        {
+            // Make an end iterator on errors
+            it.m_imp.reset();
+        }
+        else
+        {
+            if ((push_result & keep_depth) != 0u)
+            {
+                system::error_code increment_ec;
+                directory_iterator& dir_it = imp->m_stack.back();
+                detail::directory_iterator_increment(dir_it, &increment_ec);
+                if (!increment_ec && !dir_it.is_end())
+                    goto on_error_return;
+            }
+
+            recursive_directory_iterator_pop_on_error(imp);
+
+            if (imp->m_stack.empty())
+                it.m_imp.reset(); // done, so make end iterator
+        }
+
+    on_error_return:
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("filesystem::recursive_directory_iterator increment error", local_ec));
+
+        *ec = local_ec;
+        return;
+    }
+
+    //  Do the actual increment operation on the top iterator in the iterator
+    //  stack, popping the stack if necessary, until either the stack is empty or a
+    //  non-end iterator is reached.
+    while (true)
+    {
+        if (imp->m_stack.empty())
+        {
+            it.m_imp.reset(); // done, so make end iterator
+            break;
+        }
+
+        directory_iterator& dir_it = imp->m_stack.back();
+        detail::directory_iterator_increment(dir_it, &local_ec);
+        if (BOOST_UNLIKELY(!!local_ec))
+            goto on_error;
+
+        if (!dir_it.is_end())
+            break;
+
+        imp->m_stack.pop_back();
+    }
+}
+
+} // namespace detail
+
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
diff --git a/contrib/restricted/boost/filesystem/src/error_handling.hpp b/contrib/restricted/boost/filesystem/src/error_handling.hpp
new file mode 100644
index 0000000000..a83d92e976
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/error_handling.hpp
@@ -0,0 +1,237 @@
+//  error_handling.hpp  --------------------------------------------------------------------//
+
+//  Copyright 2002-2009, 2014 Beman Dawes
+//  Copyright 2019 Andrey Semashev
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  See library home page at http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#ifndef BOOST_FILESYSTEM_SRC_ERROR_HANDLING_HPP_
+#define BOOST_FILESYSTEM_SRC_ERROR_HANDLING_HPP_
+
+#include <cerrno>
+#include <boost/system/error_code.hpp>
+#include <boost/filesystem/config.hpp>
+#include <boost/filesystem/exception.hpp>
+
+#if defined(BOOST_WINDOWS_API)
+#include <boost/winapi/basic_types.hpp>
+#include <boost/winapi/get_last_error.hpp>
+#include <boost/winapi/error_codes.hpp>
+#endif
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+namespace boost {
+namespace filesystem {
+
+#if defined(BOOST_POSIX_API)
+
+typedef int err_t;
+
+//  POSIX uses a 0 return to indicate success
+#define BOOST_ERRNO errno
+
+#define BOOST_ERROR_FILE_NOT_FOUND ENOENT
+#define BOOST_ERROR_ALREADY_EXISTS EEXIST
+#define BOOST_ERROR_NOT_SUPPORTED ENOSYS
+
+#else
+
+typedef boost::winapi::DWORD_ err_t;
+
+//  Windows uses a non-0 return to indicate success
+#define BOOST_ERRNO boost::winapi::GetLastError()
+
+#define BOOST_ERROR_FILE_NOT_FOUND boost::winapi::ERROR_FILE_NOT_FOUND_
+#define BOOST_ERROR_ALREADY_EXISTS boost::winapi::ERROR_ALREADY_EXISTS_
+#define BOOST_ERROR_NOT_SUPPORTED boost::winapi::ERROR_NOT_SUPPORTED_
+
+// Note: Legacy MinGW doesn't have ntstatus.h and doesn't define NTSTATUS error codes other than STATUS_SUCCESS.
+#if !defined(NT_SUCCESS)
+#define NT_SUCCESS(Status) (((boost::winapi::NTSTATUS_)(Status)) >= 0)
+#endif
+#if !defined(STATUS_SUCCESS)
+#define STATUS_SUCCESS ((boost::winapi::NTSTATUS_)0x00000000l)
+#endif
+#if !defined(STATUS_NOT_IMPLEMENTED)
+#define STATUS_NOT_IMPLEMENTED ((boost::winapi::NTSTATUS_)0xC0000002l)
+#endif
+#if !defined(STATUS_INVALID_INFO_CLASS)
+#define STATUS_INVALID_INFO_CLASS ((boost::winapi::NTSTATUS_)0xC0000003l)
+#endif
+#if !defined(STATUS_INVALID_HANDLE)
+#define STATUS_INVALID_HANDLE ((boost::winapi::NTSTATUS_)0xC0000008l)
+#endif
+#if !defined(STATUS_INVALID_PARAMETER)
+#define STATUS_INVALID_PARAMETER ((boost::winapi::NTSTATUS_)0xC000000Dl)
+#endif
+#if !defined(STATUS_NO_SUCH_DEVICE)
+#define STATUS_NO_SUCH_DEVICE ((boost::winapi::NTSTATUS_)0xC000000El)
+#endif
+#if !defined(STATUS_NO_SUCH_FILE)
+#define STATUS_NO_SUCH_FILE ((boost::winapi::NTSTATUS_)0xC000000Fl)
+#endif
+#if !defined(STATUS_NO_MORE_FILES)
+#define STATUS_NO_MORE_FILES ((boost::winapi::NTSTATUS_)0x80000006l)
+#endif
+#if !defined(STATUS_BUFFER_OVERFLOW)
+#define STATUS_BUFFER_OVERFLOW ((boost::winapi::NTSTATUS_)0x80000005l)
+#endif
+#if !defined(STATUS_NO_MEMORY)
+#define STATUS_NO_MEMORY ((boost::winapi::NTSTATUS_)0xC0000017l)
+#endif
+#if !defined(STATUS_ACCESS_DENIED)
+#define STATUS_ACCESS_DENIED ((boost::winapi::NTSTATUS_)0xC0000022l)
+#endif
+#if !defined(STATUS_OBJECT_NAME_NOT_FOUND)
+#define STATUS_OBJECT_NAME_NOT_FOUND ((boost::winapi::NTSTATUS_)0xC0000034l)
+#endif
+#if !defined(STATUS_OBJECT_PATH_NOT_FOUND)
+#define STATUS_OBJECT_PATH_NOT_FOUND ((boost::winapi::NTSTATUS_)0xC000003Al)
+#endif
+#if !defined(STATUS_SHARING_VIOLATION)
+#define STATUS_SHARING_VIOLATION ((boost::winapi::NTSTATUS_)0xC0000043l)
+#endif
+#if !defined(STATUS_EAS_NOT_SUPPORTED)
+#define STATUS_EAS_NOT_SUPPORTED ((boost::winapi::NTSTATUS_)0xC000004Fl)
+#endif
+#if !defined(STATUS_NOT_SUPPORTED)
+#define STATUS_NOT_SUPPORTED ((boost::winapi::NTSTATUS_)0xC00000BBl)
+#endif
+#if !defined(STATUS_BAD_NETWORK_PATH)
+#define STATUS_BAD_NETWORK_PATH ((boost::winapi::NTSTATUS_)0xC00000BEl)
+#endif
+#if !defined(STATUS_DEVICE_DOES_NOT_EXIST)
+#define STATUS_DEVICE_DOES_NOT_EXIST ((boost::winapi::NTSTATUS_)0xC00000C0l)
+#endif
+#if !defined(STATUS_BAD_NETWORK_NAME)
+#define STATUS_BAD_NETWORK_NAME ((boost::winapi::NTSTATUS_)0xC00000CCl)
+#endif
+#if !defined(STATUS_DIRECTORY_NOT_EMPTY)
+#define STATUS_DIRECTORY_NOT_EMPTY ((boost::winapi::NTSTATUS_)0xC0000101l)
+#endif
+#if !defined(STATUS_NOT_A_DIRECTORY)
+#define STATUS_NOT_A_DIRECTORY ((boost::winapi::NTSTATUS_)0xC0000103l)
+#endif
+#if !defined(STATUS_NOT_FOUND)
+#define STATUS_NOT_FOUND ((boost::winapi::NTSTATUS_)0xC0000225l)
+#endif
+
+//! Converts NTSTATUS error codes to Win32 error codes for reporting
+inline boost::winapi::DWORD_ translate_ntstatus(boost::winapi::NTSTATUS_ status) noexcept
+{
+    // We have to cast to unsigned integral type to avoid signed overflow and narrowing conversion in the constants.
+    switch (static_cast< boost::winapi::ULONG_ >(status))
+    {
+    case static_cast< boost::winapi::ULONG_ >(STATUS_NO_MEMORY):
+        return boost::winapi::ERROR_OUTOFMEMORY_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_BUFFER_OVERFLOW):
+        return boost::winapi::ERROR_BUFFER_OVERFLOW_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_INVALID_HANDLE):
+        return boost::winapi::ERROR_INVALID_HANDLE_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_INVALID_PARAMETER):
+        return boost::winapi::ERROR_INVALID_PARAMETER_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_NO_MORE_FILES):
+        return boost::winapi::ERROR_NO_MORE_FILES_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_NO_SUCH_DEVICE):
+    case static_cast< boost::winapi::ULONG_ >(STATUS_DEVICE_DOES_NOT_EXIST):
+        return boost::winapi::ERROR_DEV_NOT_EXIST_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_NO_SUCH_FILE):
+    case static_cast< boost::winapi::ULONG_ >(STATUS_OBJECT_NAME_NOT_FOUND):
+    case static_cast< boost::winapi::ULONG_ >(STATUS_OBJECT_PATH_NOT_FOUND):
+        return boost::winapi::ERROR_FILE_NOT_FOUND_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_SHARING_VIOLATION):
+        return boost::winapi::ERROR_SHARING_VIOLATION_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_EAS_NOT_SUPPORTED):
+        return boost::winapi::ERROR_EAS_NOT_SUPPORTED_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_ACCESS_DENIED):
+        return boost::winapi::ERROR_ACCESS_DENIED_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_BAD_NETWORK_PATH):
+        return boost::winapi::ERROR_BAD_NETPATH_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_BAD_NETWORK_NAME):
+        return boost::winapi::ERROR_BAD_NET_NAME_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_DIRECTORY_NOT_EMPTY):
+        return boost::winapi::ERROR_DIR_NOT_EMPTY_;
+    case static_cast< boost::winapi::ULONG_ >(STATUS_NOT_A_DIRECTORY):
+        return boost::winapi::ERROR_DIRECTORY_; // The directory name is invalid
+    case static_cast< boost::winapi::ULONG_ >(STATUS_NOT_FOUND):
+        return boost::winapi::ERROR_NOT_FOUND_;
+    // map "invalid info class" to "not supported" as this error likely indicates that the kernel does not support what we request
+    case static_cast< boost::winapi::ULONG_ >(STATUS_INVALID_INFO_CLASS):
+    default:
+        return boost::winapi::ERROR_NOT_SUPPORTED_;
+    }
+}
+
+//! Tests if the NTSTATUS indicates that the file is not found
+inline bool not_found_ntstatus(boost::winapi::NTSTATUS_ status) noexcept
+{
+    return status == STATUS_NO_SUCH_FILE || status == STATUS_OBJECT_NAME_NOT_FOUND || status == STATUS_OBJECT_PATH_NOT_FOUND ||
+        status == STATUS_BAD_NETWORK_PATH || status == STATUS_BAD_NETWORK_NAME;
+}
+
+#endif
+
+//  error handling helpers  ----------------------------------------------------------//
+
+// Implemented in exception.cpp
+void emit_error(err_t error_num, system::error_code* ec, const char* message);
+void emit_error(err_t error_num, path const& p, system::error_code* ec, const char* message);
+void emit_error(err_t error_num, path const& p1, path const& p2, system::error_code* ec, const char* message);
+
+inline bool error(err_t error_num, system::error_code* ec, const char* message)
+{
+    if (BOOST_LIKELY(!error_num))
+    {
+        if (ec)
+            ec->clear();
+        return false;
+    }
+    else
+    { //  error
+        filesystem::emit_error(error_num, ec, message);
+        return true;
+    }
+}
+
+inline bool error(err_t error_num, path const& p, system::error_code* ec, const char* message)
+{
+    if (BOOST_LIKELY(!error_num))
+    {
+        if (ec)
+            ec->clear();
+        return false;
+    }
+    else
+    { //  error
+        filesystem::emit_error(error_num, p, ec, message);
+        return true;
+    }
+}
+
+inline bool error(err_t error_num, path const& p1, path const& p2, system::error_code* ec, const char* message)
+{
+    if (BOOST_LIKELY(!error_num))
+    {
+        if (ec)
+            ec->clear();
+        return false;
+    }
+    else
+    { //  error
+        filesystem::emit_error(error_num, p1, p2, ec, message);
+        return true;
+    }
+}
+
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
+
+#endif // BOOST_FILESYSTEM_SRC_ERROR_HANDLING_HPP_
diff --git a/contrib/restricted/boost/filesystem/src/exception.cpp b/contrib/restricted/boost/filesystem/src/exception.cpp
new file mode 100644
index 0000000000..0b92c0d9c1
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/exception.cpp
@@ -0,0 +1,188 @@
+//  boost/filesystem/exception.hpp  -----------------------------------------------------//
+
+//  Copyright Beman Dawes 2003
+//  Copyright Andrey Semashev 2019
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  Library home page: http://www.boost.org/libs/filesystem
+
+#include "platform_config.hpp"
+
+#include <string>
+#include <boost/system/error_code.hpp>
+#include <boost/system/system_category.hpp>
+#include <boost/filesystem/config.hpp>
+#include <boost/filesystem/path.hpp>
+#include <boost/filesystem/exception.hpp>
+
+#include "error_handling.hpp"
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+namespace boost {
+namespace filesystem {
+
+BOOST_FILESYSTEM_DECL filesystem_error::filesystem_error(const char* what_arg, system::error_code ec) :
+    system::system_error(ec, what_arg)
+{
+    try
+    {
+        m_imp_ptr.reset(new impl());
+    }
+    catch (...)
+    {
+        m_imp_ptr.reset();
+    }
+}
+
+BOOST_FILESYSTEM_DECL filesystem_error::filesystem_error(std::string const& what_arg, system::error_code ec) :
+    system::system_error(ec, what_arg)
+{
+    try
+    {
+        m_imp_ptr.reset(new impl());
+    }
+    catch (...)
+    {
+        m_imp_ptr.reset();
+    }
+}
+
+BOOST_FILESYSTEM_DECL filesystem_error::filesystem_error(const char* what_arg, path const& path1_arg, system::error_code ec) :
+    system::system_error(ec, what_arg)
+{
+    try
+    {
+        m_imp_ptr.reset(new impl(path1_arg));
+    }
+    catch (...)
+    {
+        m_imp_ptr.reset();
+    }
+}
+
+BOOST_FILESYSTEM_DECL filesystem_error::filesystem_error(std::string const& what_arg, path const& path1_arg, system::error_code ec) :
+    system::system_error(ec, what_arg)
+{
+    try
+    {
+        m_imp_ptr.reset(new impl(path1_arg));
+    }
+    catch (...)
+    {
+        m_imp_ptr.reset();
+    }
+}
+
+BOOST_FILESYSTEM_DECL filesystem_error::filesystem_error(const char* what_arg, path const& path1_arg, path const& path2_arg, system::error_code ec) :
+    system::system_error(ec, what_arg)
+{
+    try
+    {
+        m_imp_ptr.reset(new impl(path1_arg, path2_arg));
+    }
+    catch (...)
+    {
+        m_imp_ptr.reset();
+    }
+}
+
+BOOST_FILESYSTEM_DECL filesystem_error::filesystem_error(std::string const& what_arg, path const& path1_arg, path const& path2_arg, system::error_code ec) :
+    system::system_error(ec, what_arg)
+{
+    try
+    {
+        m_imp_ptr.reset(new impl(path1_arg, path2_arg));
+    }
+    catch (...)
+    {
+        m_imp_ptr.reset();
+    }
+}
+
+BOOST_FILESYSTEM_DECL filesystem_error::filesystem_error(filesystem_error const& that) :
+    system::system_error(static_cast< system::system_error const& >(that)),
+    m_imp_ptr(that.m_imp_ptr)
+{
+}
+
+BOOST_FILESYSTEM_DECL filesystem_error& filesystem_error::operator=(filesystem_error const& that)
+{
+    static_cast< system::system_error& >(*this) = static_cast< system::system_error const& >(that);
+    m_imp_ptr = that.m_imp_ptr;
+    return *this;
+}
+
+BOOST_FILESYSTEM_DECL filesystem_error::~filesystem_error() noexcept
+{
+}
+
+BOOST_FILESYSTEM_DECL const char* filesystem_error::what() const noexcept
+{
+    if (m_imp_ptr.get()) try
+    {
+        if (m_imp_ptr->m_what.empty())
+        {
+            m_imp_ptr->m_what = system::system_error::what();
+            if (!m_imp_ptr->m_path1.empty())
+            {
+                m_imp_ptr->m_what += ": \"";
+                m_imp_ptr->m_what += m_imp_ptr->m_path1.string();
+                m_imp_ptr->m_what += "\"";
+            }
+            if (!m_imp_ptr->m_path2.empty())
+            {
+                m_imp_ptr->m_what += ", \"";
+                m_imp_ptr->m_what += m_imp_ptr->m_path2.string();
+                m_imp_ptr->m_what += "\"";
+            }
+        }
+
+        return m_imp_ptr->m_what.c_str();
+    }
+    catch (...)
+    {
+        m_imp_ptr->m_what.clear();
+    }
+
+    return system::system_error::what();
+}
+
+BOOST_FILESYSTEM_DECL path const& filesystem_error::get_empty_path() noexcept
+{
+    static const path empty_path;
+    return empty_path;
+}
+
+//  error handling helpers declared in error_handling.hpp  -----------------------------------------------------//
+
+void emit_error(err_t error_num, system::error_code* ec, const char* message)
+{
+    if (!ec)
+        BOOST_FILESYSTEM_THROW(filesystem_error(message, system::error_code(error_num, system::system_category())));
+    else
+        ec->assign(error_num, system::system_category());
+}
+
+void emit_error(err_t error_num, path const& p, system::error_code* ec, const char* message)
+{
+    if (!ec)
+        BOOST_FILESYSTEM_THROW(filesystem_error(message, p, system::error_code(error_num, system::system_category())));
+    else
+        ec->assign(error_num, system::system_category());
+}
+
+void emit_error(err_t error_num, path const& p1, path const& p2, system::error_code* ec, const char* message)
+{
+    if (!ec)
+        BOOST_FILESYSTEM_THROW(filesystem_error(message, p1, p2, system::error_code(error_num, system::system_category())));
+    else
+        ec->assign(error_num, system::system_category());
+}
+
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
diff --git a/contrib/restricted/boost/filesystem/src/operations.cpp b/contrib/restricted/boost/filesystem/src/operations.cpp
new file mode 100644
index 0000000000..e2fa235451
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/operations.cpp
@@ -0,0 +1,5202 @@
+//  operations.cpp  --------------------------------------------------------------------//
+
+//  Copyright 2002-2009, 2014 Beman Dawes
+//  Copyright 2001 Dietmar Kuehl
+//  Copyright 2018-2024 Andrey Semashev
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  See library home page at http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#include "platform_config.hpp"
+
+#include <boost/predef/os/bsd/open.h>
+#include <boost/filesystem/config.hpp>
+#include <boost/filesystem/operations.hpp>
+#include <boost/filesystem/file_status.hpp>
+#include <boost/filesystem/exception.hpp>
+#include <boost/filesystem/directory.hpp>
+#include <boost/system/error_code.hpp>
+#include <boost/detail/workaround.hpp>
+#include <boost/core/bit.hpp>
+#include <boost/cstdint.hpp>
+#include <boost/assert.hpp>
+#include <new> // std::bad_alloc, std::nothrow
+#include <limits>
+#include <memory>
+#include <string>
+#include <utility>
+#include <cstddef>
+#include <cstdlib> // for malloc, free
+#include <cstring>
+#include <cerrno>
+#include <stdio.h> // for rename
+
+// Default to POSIX under Emscripten
+// If BOOST_FILESYSTEM_EMSCRIPTEN_USE_WASI is set, use WASI instead
+#if defined(__wasm) && (!defined(__EMSCRIPTEN__) || defined(BOOST_FILESYSTEM_EMSCRIPTEN_USE_WASI))
+#define BOOST_FILESYSTEM_USE_WASI
+#endif
+
+#ifdef BOOST_POSIX_API
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#if defined(BOOST_FILESYSTEM_USE_WASI)
+// WASI does not have statfs or statvfs.
+#elif !defined(__APPLE__) && \
+    (!defined(__OpenBSD__) || BOOST_OS_BSD_OPEN >= BOOST_VERSION_NUMBER(4, 4, 0)) && \
+    !defined(__ANDROID__) && \
+    !defined(__VXWORKS__)
+#include <sys/statvfs.h>
+#define BOOST_STATVFS statvfs
+#define BOOST_STATVFS_F_FRSIZE vfs.f_frsize
+#else
+#ifdef __OpenBSD__
+#include <sys/param.h>
+#elif defined(__ANDROID__)
+#include <sys/vfs.h>
+#endif
+#if !defined(__VXWORKS__)
+#include <sys/mount.h>
+#endif
+#define BOOST_STATVFS statfs
+#define BOOST_STATVFS_F_FRSIZE static_cast< uintmax_t >(vfs.f_bsize)
+#endif // BOOST_STATVFS definition
+
+#include <unistd.h>
+#include <fcntl.h>
+#if !defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+#include <utime.h>
+#endif
+#include <limits.h>
+
+#if defined(linux) || defined(__linux) || defined(__linux__)
+
+#include <sys/vfs.h>
+#include <sys/utsname.h>
+#include <sys/syscall.h>
+#include <sys/sysmacros.h>
+#if !defined(BOOST_FILESYSTEM_DISABLE_SENDFILE)
+#include <sys/sendfile.h>
+#define BOOST_FILESYSTEM_USE_SENDFILE
+#endif // !defined(BOOST_FILESYSTEM_DISABLE_SENDFILE)
+#if !defined(BOOST_FILESYSTEM_DISABLE_COPY_FILE_RANGE) && defined(__NR_copy_file_range)
+#define BOOST_FILESYSTEM_USE_COPY_FILE_RANGE
+#endif // !defined(BOOST_FILESYSTEM_DISABLE_COPY_FILE_RANGE) && defined(__NR_copy_file_range)
+#if !defined(BOOST_FILESYSTEM_DISABLE_STATX) && (defined(BOOST_FILESYSTEM_HAS_STATX) || defined(BOOST_FILESYSTEM_HAS_STATX_SYSCALL))
+#if !defined(BOOST_FILESYSTEM_HAS_STATX) && defined(BOOST_FILESYSTEM_HAS_STATX_SYSCALL)
+#include <linux/stat.h>
+#endif
+#define BOOST_FILESYSTEM_USE_STATX
+#endif // !defined(BOOST_FILESYSTEM_DISABLE_STATX) && (defined(BOOST_FILESYSTEM_HAS_STATX) || defined(BOOST_FILESYSTEM_HAS_STATX_SYSCALL))
+
+#if defined(__has_include)
+#if __has_include(<linux/magic.h>)
+// This header was introduced in Linux kernel 2.6.19
+#include <linux/magic.h>
+#endif
+#endif
+
+// Some filesystem type magic constants are not defined in older kernel headers
+#ifndef PROC_SUPER_MAGIC
+#define PROC_SUPER_MAGIC 0x9fa0
+#endif
+#ifndef SYSFS_MAGIC
+#define SYSFS_MAGIC 0x62656572
+#endif
+#ifndef TRACEFS_MAGIC
+#define TRACEFS_MAGIC 0x74726163
+#endif
+#ifndef DEBUGFS_MAGIC
+#define DEBUGFS_MAGIC 0x64626720
+#endif
+
+#endif // defined(linux) || defined(__linux) || defined(__linux__)
+
+#include <boost/scope/unique_fd.hpp>
+
+#if defined(POSIX_FADV_SEQUENTIAL) && (!defined(__ANDROID__) || __ANDROID_API__ >= 21)
+#define BOOST_FILESYSTEM_HAS_POSIX_FADVISE
+#endif
+
+#if defined(BOOST_FILESYSTEM_HAS_STAT_ST_MTIM)
+#define BOOST_FILESYSTEM_STAT_ST_MTIMENSEC st_mtim.tv_nsec
+#elif defined(BOOST_FILESYSTEM_HAS_STAT_ST_MTIMESPEC)
+#define BOOST_FILESYSTEM_STAT_ST_MTIMENSEC st_mtimespec.tv_nsec
+#elif defined(BOOST_FILESYSTEM_HAS_STAT_ST_MTIMENSEC)
+#define BOOST_FILESYSTEM_STAT_ST_MTIMENSEC st_mtimensec
+#endif
+
+#if defined(BOOST_FILESYSTEM_HAS_STAT_ST_BIRTHTIM)
+#define BOOST_FILESYSTEM_STAT_ST_BIRTHTIME st_birthtim.tv_sec
+#define BOOST_FILESYSTEM_STAT_ST_BIRTHTIMENSEC st_birthtim.tv_nsec
+#elif defined(BOOST_FILESYSTEM_HAS_STAT_ST_BIRTHTIMESPEC)
+#define BOOST_FILESYSTEM_STAT_ST_BIRTHTIME st_birthtimespec.tv_sec
+#define BOOST_FILESYSTEM_STAT_ST_BIRTHTIMENSEC st_birthtimespec.tv_nsec
+#elif defined(BOOST_FILESYSTEM_HAS_STAT_ST_BIRTHTIMENSEC)
+#define BOOST_FILESYSTEM_STAT_ST_BIRTHTIME st_birthtime
+#define BOOST_FILESYSTEM_STAT_ST_BIRTHTIMENSEC st_birthtimensec
+#endif
+
+#include "posix_tools.hpp"
+
+#else // BOOST_WINDOWS_API
+
+#include <boost/winapi/dll.hpp> // get_proc_address, GetModuleHandleW
+#include <cwchar>
+#include <io.h>
+#include <windows.h>
+#include <winnt.h>
+#if defined(__BORLANDC__) || defined(__MWERKS__)
+#if defined(BOOST_BORLANDC)
+using std::time_t;
+#endif
+#include <utime.h>
+#else
+#include <sys/utime.h>
+#endif
+
+#include "windows_tools.hpp"
+
+#endif // BOOST_WINDOWS_API
+
+#include "atomic_tools.hpp"
+#include "error_handling.hpp"
+#include "private_config.hpp"
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+namespace fs = boost::filesystem;
+using boost::filesystem::path;
+using boost::filesystem::filesystem_error;
+using boost::filesystem::perms;
+using boost::system::error_code;
+using boost::system::system_category;
+
+#if defined(BOOST_POSIX_API)
+
+// At least Mac OS X 10.6 and older doesn't support O_CLOEXEC
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#define BOOST_FILESYSTEM_NO_O_CLOEXEC
+#endif
+
+#if defined(_POSIX_SYNCHRONIZED_IO) && _POSIX_SYNCHRONIZED_IO > 0
+#define BOOST_FILESYSTEM_HAS_FDATASYNC
+#endif
+
+#else // defined(BOOST_POSIX_API)
+
+#ifndef MAXIMUM_REPARSE_DATA_BUFFER_SIZE
+#define MAXIMUM_REPARSE_DATA_BUFFER_SIZE (16 * 1024)
+#endif
+
+#ifndef FSCTL_GET_REPARSE_POINT
+#define FSCTL_GET_REPARSE_POINT 0x900a8
+#endif
+
+#ifndef SYMLINK_FLAG_RELATIVE
+#define SYMLINK_FLAG_RELATIVE 1
+#endif
+
+// Fallback for MinGW/Cygwin
+#ifndef SYMBOLIC_LINK_FLAG_DIRECTORY
+#define SYMBOLIC_LINK_FLAG_DIRECTORY 0x1
+#endif
+
+#ifndef SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE
+#define SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE 0x2
+#endif
+
+#endif // defined(BOOST_POSIX_API)
+
+//  POSIX/Windows macros  ----------------------------------------------------//
+
+//  Portions of the POSIX and Windows API's are very similar, except for name,
+//  order of arguments, and meaning of zero/non-zero returns. The macros below
+//  abstract away those differences. They follow Windows naming and order of
+//  arguments, and return true to indicate no error occurred. [POSIX naming,
+//  order of arguments, and meaning of return were followed initially, but
+//  found to be less clear and cause more coding errors.]
+
+#if defined(BOOST_POSIX_API)
+
+#define BOOST_SET_CURRENT_DIRECTORY(P) (::chdir(P) == 0)
+#define BOOST_MOVE_FILE(OLD, NEW) (::rename(OLD, NEW) == 0)
+#define BOOST_RESIZE_FILE(P, SZ) (::truncate(P, SZ) == 0)
+
+#else // BOOST_WINDOWS_API
+
+#define BOOST_SET_CURRENT_DIRECTORY(P) (::SetCurrentDirectoryW(P) != 0)
+#define BOOST_MOVE_FILE(OLD, NEW) (::MoveFileExW(OLD, NEW, MOVEFILE_REPLACE_EXISTING | MOVEFILE_COPY_ALLOWED) != 0)
+#define BOOST_RESIZE_FILE(P, SZ) (resize_file_impl(P, SZ) != 0)
+
+#endif
+
+namespace boost {
+namespace filesystem {
+namespace detail {
+
+#if defined(linux) || defined(__linux) || defined(__linux__)
+//! Initializes fill_random implementation pointer. Implemented in unique_path.cpp.
+void init_fill_random_impl(unsigned int major_ver, unsigned int minor_ver, unsigned int patch_ver);
+#endif // defined(linux) || defined(__linux) || defined(__linux__)
+
+#if defined(BOOST_WINDOWS_API)
+//! Initializes directory iterator implementation. Implemented in directory.cpp.
+void init_directory_iterator_impl() noexcept;
+#endif // defined(BOOST_WINDOWS_API)
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//                        helpers (all operating systems)                               //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+namespace {
+
+// The number of retries remove_all should make if it detects that the directory it is about to enter has been replaced with a symlink or a regular file
+BOOST_CONSTEXPR_OR_CONST unsigned int remove_all_directory_replaced_retry_count = 5u;
+
+#if defined(BOOST_POSIX_API)
+
+// Size of a small buffer for a path that can be placed on stack, in character code units
+BOOST_CONSTEXPR_OR_CONST std::size_t small_path_size = 1024u;
+
+// Absolute maximum path length, in character code units, that we're willing to accept from various system calls.
+// This value is arbitrary, it is supposed to be a hard limit to avoid memory exhaustion
+// in some of the algorithms below in case of some corrupted or maliciously broken filesystem.
+// A few examples of path size limits:
+// - Windows: 32767 UTF-16 code units or 260 bytes for legacy multibyte APIs.
+// - Linux: 4096 bytes
+// - IRIX, HP-UX, Mac OS, QNX, FreeBSD, OpenBSD: 1024 bytes
+// - GNU/Hurd: no hard limit
+BOOST_CONSTEXPR_OR_CONST std::size_t absolute_path_max = 32u * 1024u;
+
+#endif // defined(BOOST_POSIX_API)
+
+// Maximum number of resolved symlinks before we register a loop
+BOOST_CONSTEXPR_OR_CONST unsigned int symloop_max =
+#if defined(SYMLOOP_MAX)
+    SYMLOOP_MAX < 40 ? 40 : SYMLOOP_MAX
+#else
+    40
+#endif
+;
+
+//  general helpers  -----------------------------------------------------------------//
+
+#ifdef BOOST_POSIX_API
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//                            POSIX-specific helpers                                    //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+inline bool not_found_error(int errval) noexcept
+{
+    return errval == ENOENT || errval == ENOTDIR;
+}
+
+/*!
+ * Closes a file descriptor and returns the result, similar to close(2). Unlike close(2), guarantees that the file descriptor is closed even if EINTR error happens.
+ *
+ * Some systems don't close the file descriptor in case if the thread is interrupted by a signal and close(2) returns EINTR.
+ * Other (most) systems do close the file descriptor even when when close(2) returns EINTR, and attempting to close it
+ * again could close a different file descriptor that was opened by a different thread. This function hides this difference in behavior.
+ *
+ * Future POSIX standards will likely fix this by introducing posix_close (see https://www.austingroupbugs.net/view.php?id=529)
+ * and prohibiting returning EINTR from close(2), but we still have to support older systems where this new behavior is not available and close(2)
+ * behaves differently between systems.
+ */
+inline int close_fd(int fd)
+{
+#if defined(hpux) || defined(_hpux) || defined(__hpux)
+    int res;
+    while (true)
+    {
+        res = ::close(fd);
+        if (BOOST_UNLIKELY(res < 0))
+        {
+            int err = errno;
+            if (err == EINTR)
+                continue;
+        }
+
+        break;
+    }
+
+    return res;
+#else
+    return ::close(fd);
+#endif
+}
+
+#if defined(BOOST_FILESYSTEM_HAS_STATX)
+
+//! A wrapper for statx libc function. Disable MSAN since at least on clang 10 it doesn't
+//! know which fields of struct statx are initialized by the syscall and misdetects errors.
+BOOST_FILESYSTEM_NO_SANITIZE_MEMORY
+BOOST_FORCEINLINE int invoke_statx(int dirfd, const char* path, int flags, unsigned int mask, struct ::statx* stx)
+{
+    return ::statx(dirfd, path, flags, mask, stx);
+}
+
+#elif defined(BOOST_FILESYSTEM_HAS_STATX_SYSCALL)
+
+//! statx emulation through fstatat
+int statx_fstatat(int dirfd, const char* path, int flags, unsigned int mask, struct ::statx* stx)
+{
+    struct ::stat st;
+    flags &= AT_EMPTY_PATH | AT_NO_AUTOMOUNT | AT_SYMLINK_NOFOLLOW;
+    int res = ::fstatat(dirfd, path, &st, flags);
+    if (BOOST_LIKELY(res == 0))
+    {
+        std::memset(stx, 0, sizeof(*stx));
+        stx->stx_mask = STATX_BASIC_STATS;
+        stx->stx_blksize = st.st_blksize;
+        stx->stx_nlink = st.st_nlink;
+        stx->stx_uid = st.st_uid;
+        stx->stx_gid = st.st_gid;
+        stx->stx_mode = st.st_mode;
+        stx->stx_ino = st.st_ino;
+        stx->stx_size = st.st_size;
+        stx->stx_blocks = st.st_blocks;
+        stx->stx_atime.tv_sec = st.st_atim.tv_sec;
+        stx->stx_atime.tv_nsec = st.st_atim.tv_nsec;
+        stx->stx_ctime.tv_sec = st.st_ctim.tv_sec;
+        stx->stx_ctime.tv_nsec = st.st_ctim.tv_nsec;
+        stx->stx_mtime.tv_sec = st.st_mtim.tv_sec;
+        stx->stx_mtime.tv_nsec = st.st_mtim.tv_nsec;
+        stx->stx_rdev_major = major(st.st_rdev);
+        stx->stx_rdev_minor = minor(st.st_rdev);
+        stx->stx_dev_major = major(st.st_dev);
+        stx->stx_dev_minor = minor(st.st_dev);
+    }
+
+    return res;
+}
+
+typedef int statx_t(int dirfd, const char* path, int flags, unsigned int mask, struct ::statx* stx);
+
+//! Pointer to the actual implementation of the statx implementation
+statx_t* statx_ptr = &statx_fstatat;
+
+inline int invoke_statx(int dirfd, const char* path, int flags, unsigned int mask, struct ::statx* stx) noexcept
+{
+    return filesystem::detail::atomic_load_relaxed(statx_ptr)(dirfd, path, flags, mask, stx);
+}
+
+//! A wrapper for the statx syscall. Disable MSAN since at least on clang 10 it doesn't
+//! know which fields of struct statx are initialized by the syscall and misdetects errors.
+BOOST_FILESYSTEM_NO_SANITIZE_MEMORY
+int statx_syscall(int dirfd, const char* path, int flags, unsigned int mask, struct ::statx* stx)
+{
+    int res = ::syscall(__NR_statx, dirfd, path, flags, mask, stx);
+    if (res < 0)
+    {
+        const int err = errno;
+        if (BOOST_UNLIKELY(err == ENOSYS))
+        {
+            filesystem::detail::atomic_store_relaxed(statx_ptr, &statx_fstatat);
+            return statx_fstatat(dirfd, path, flags, mask, stx);
+        }
+    }
+
+    return res;
+}
+
+#endif // defined(BOOST_FILESYSTEM_HAS_STATX)
+
+#if defined(linux) || defined(__linux) || defined(__linux__)
+
+//! Initializes statx implementation pointer
+inline void init_statx_impl(unsigned int major_ver, unsigned int minor_ver, unsigned int patch_ver)
+{
+#if !defined(BOOST_FILESYSTEM_HAS_STATX) && defined(BOOST_FILESYSTEM_HAS_STATX_SYSCALL)
+    statx_t* stx = &statx_fstatat;
+    if (major_ver > 4u || (major_ver == 4u && minor_ver >= 11u))
+        stx = &statx_syscall;
+
+    filesystem::detail::atomic_store_relaxed(statx_ptr, stx);
+#endif // !defined(BOOST_FILESYSTEM_HAS_STATX) && defined(BOOST_FILESYSTEM_HAS_STATX_SYSCALL)
+}
+
+#endif // defined(linux) || defined(__linux) || defined(__linux__)
+
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+
+//! Returns \c true if the two \c statx structures refer to the same file
+inline bool equivalent_stat(struct ::statx const& s1, struct ::statx const& s2) noexcept
+{
+    return s1.stx_dev_major == s2.stx_dev_major && s1.stx_dev_minor == s2.stx_dev_minor && s1.stx_ino == s2.stx_ino;
+}
+
+//! Returns file type/access mode from \c statx structure
+inline mode_t get_mode(struct ::statx const& st) noexcept
+{
+    return st.stx_mode;
+}
+
+//! Returns file size from \c statx structure
+inline uintmax_t get_size(struct ::statx const& st) noexcept
+{
+    return st.stx_size;
+}
+
+//! Returns optimal block size from \c statx structure
+inline std::size_t get_blksize(struct ::statx const& st) noexcept
+{
+    return st.stx_blksize;
+}
+
+#else // defined(BOOST_FILESYSTEM_USE_STATX)
+
+//! Returns \c true if the two \c stat structures refer to the same file
+inline bool equivalent_stat(struct ::stat const& s1, struct ::stat const& s2) noexcept
+{
+    // According to the POSIX stat specs, "The st_ino and st_dev fields
+    // taken together uniquely identify the file within the system."
+    return s1.st_dev == s2.st_dev && s1.st_ino == s2.st_ino;
+}
+
+//! Returns file type/access mode from \c stat structure
+inline mode_t get_mode(struct ::stat const& st) noexcept
+{
+    return st.st_mode;
+}
+
+//! Returns file size from \c stat structure
+inline uintmax_t get_size(struct ::stat const& st) noexcept
+{
+    return st.st_size;
+}
+
+//! Returns optimal block size from \c stat structure
+inline std::size_t get_blksize(struct ::stat const& st) noexcept
+{
+#if defined(BOOST_FILESYSTEM_HAS_STAT_ST_BLKSIZE)
+    return st.st_blksize;
+#else
+    return 4096u; // a suitable default used on most modern SSDs/HDDs
+#endif
+}
+
+#endif // defined(BOOST_FILESYSTEM_USE_STATX)
+
+} // namespace
+
+//! status() implementation
+file_status status_impl
+(
+    path const& p,
+    system::error_code* ec
+#if defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS) || defined(BOOST_FILESYSTEM_USE_STATX)
+    , int basedir_fd
+#endif
+)
+{
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    struct ::statx path_stat;
+    int err = invoke_statx(basedir_fd, p.c_str(), AT_NO_AUTOMOUNT, STATX_TYPE | STATX_MODE, &path_stat);
+#elif defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+    struct ::stat path_stat;
+    int err = ::fstatat(basedir_fd, p.c_str(), &path_stat, AT_NO_AUTOMOUNT);
+#else
+    struct ::stat path_stat;
+    int err = ::stat(p.c_str(), &path_stat);
+#endif
+
+    if (err != 0)
+    {
+        err = errno;
+        if (ec)                                         // always report errno, even though some
+            ec->assign(err, system::system_category()); // errno values are not status_errors
+
+        if (not_found_error(err))
+            return fs::file_status(fs::file_not_found, fs::no_perms);
+
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::status", p, system::error_code(err, system::system_category())));
+
+        return fs::file_status(fs::status_error);
+    }
+
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    if (BOOST_UNLIKELY((path_stat.stx_mask & (STATX_TYPE | STATX_MODE)) != (STATX_TYPE | STATX_MODE)))
+    {
+        emit_error(BOOST_ERROR_NOT_SUPPORTED, p, ec, "boost::filesystem::status");
+        return fs::file_status(fs::status_error);
+    }
+#endif
+
+    const mode_t mode = get_mode(path_stat);
+    if (S_ISDIR(mode))
+        return fs::file_status(fs::directory_file, static_cast< perms >(mode) & fs::perms_mask);
+    if (S_ISREG(mode))
+        return fs::file_status(fs::regular_file, static_cast< perms >(mode) & fs::perms_mask);
+    if (S_ISBLK(mode))
+        return fs::file_status(fs::block_file, static_cast< perms >(mode) & fs::perms_mask);
+    if (S_ISCHR(mode))
+        return fs::file_status(fs::character_file, static_cast< perms >(mode) & fs::perms_mask);
+    if (S_ISFIFO(mode))
+        return fs::file_status(fs::fifo_file, static_cast< perms >(mode) & fs::perms_mask);
+    if (S_ISSOCK(mode))
+        return fs::file_status(fs::socket_file, static_cast< perms >(mode) & fs::perms_mask);
+
+    return fs::file_status(fs::type_unknown);
+}
+
+//! symlink_status() implementation
+file_status symlink_status_impl
+(
+    path const& p,
+    system::error_code* ec
+#if defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS) || defined(BOOST_FILESYSTEM_USE_STATX)
+    , int basedir_fd
+#endif
+)
+{
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    struct ::statx path_stat;
+    int err = invoke_statx(basedir_fd, p.c_str(), AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT, STATX_TYPE | STATX_MODE, &path_stat);
+#elif defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+    struct ::stat path_stat;
+    int err = ::fstatat(basedir_fd, p.c_str(), &path_stat, AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT);
+#else
+    struct ::stat path_stat;
+    int err = ::lstat(p.c_str(), &path_stat);
+#endif
+
+    if (err != 0)
+    {
+        err = errno;
+        if (ec)                                         // always report errno, even though some
+            ec->assign(err, system::system_category()); // errno values are not status_errors
+
+        if (not_found_error(err)) // these are not errors
+            return fs::file_status(fs::file_not_found, fs::no_perms);
+
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::symlink_status", p, system::error_code(err, system::system_category())));
+
+        return fs::file_status(fs::status_error);
+    }
+
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    if (BOOST_UNLIKELY((path_stat.stx_mask & (STATX_TYPE | STATX_MODE)) != (STATX_TYPE | STATX_MODE)))
+    {
+        emit_error(BOOST_ERROR_NOT_SUPPORTED, p, ec, "boost::filesystem::symlink_status");
+        return fs::file_status(fs::status_error);
+    }
+#endif
+
+    const mode_t mode = get_mode(path_stat);
+    if (S_ISREG(mode))
+        return fs::file_status(fs::regular_file, static_cast< perms >(mode) & fs::perms_mask);
+    if (S_ISDIR(mode))
+        return fs::file_status(fs::directory_file, static_cast< perms >(mode) & fs::perms_mask);
+    if (S_ISLNK(mode))
+        return fs::file_status(fs::symlink_file, static_cast< perms >(mode) & fs::perms_mask);
+    if (S_ISBLK(mode))
+        return fs::file_status(fs::block_file, static_cast< perms >(mode) & fs::perms_mask);
+    if (S_ISCHR(mode))
+        return fs::file_status(fs::character_file, static_cast< perms >(mode) & fs::perms_mask);
+    if (S_ISFIFO(mode))
+        return fs::file_status(fs::fifo_file, static_cast< perms >(mode) & fs::perms_mask);
+    if (S_ISSOCK(mode))
+        return fs::file_status(fs::socket_file, static_cast< perms >(mode) & fs::perms_mask);
+
+    return fs::file_status(fs::type_unknown);
+}
+
+namespace {
+
+//! Flushes buffered data and attributes written to the file to permanent storage
+inline int full_sync(int fd)
+{
+    while (true)
+    {
+#if defined(__APPLE__) && defined(__MACH__) && defined(F_FULLFSYNC)
+        // Mac OS does not flush data to physical storage with fsync()
+        int err = ::fcntl(fd, F_FULLFSYNC);
+#else
+        int err = ::fsync(fd);
+#endif
+        if (BOOST_UNLIKELY(err < 0))
+        {
+            err = errno;
+            // POSIX says fsync can return EINTR (https://pubs.opengroup.org/onlinepubs/9699919799/functions/fsync.html).
+            // fcntl(F_FULLFSYNC) isn't documented to return EINTR, but it doesn't hurt to check.
+            if (err == EINTR)
+                continue;
+
+            return err;
+        }
+
+        break;
+    }
+
+    return 0;
+}
+
+//! Flushes buffered data written to the file to permanent storage
+inline int data_sync(int fd)
+{
+#if defined(BOOST_FILESYSTEM_HAS_FDATASYNC) && !(defined(__APPLE__) && defined(__MACH__) && defined(F_FULLFSYNC))
+    while (true)
+    {
+        int err = ::fdatasync(fd);
+        if (BOOST_UNLIKELY(err != 0))
+        {
+            err = errno;
+            // POSIX says fsync can return EINTR (https://pubs.opengroup.org/onlinepubs/9699919799/functions/fsync.html).
+            // It doesn't say so for fdatasync, but it is reasonable to expect it as well.
+            if (err == EINTR)
+                continue;
+
+            return err;
+        }
+
+        break;
+    }
+
+    return 0;
+#else
+    return full_sync(fd);
+#endif
+}
+
+//! Hints the filesystem to opportunistically preallocate storage for a file
+inline int preallocate_storage(int file, uintmax_t size)
+{
+#if defined(BOOST_FILESYSTEM_HAS_FALLOCATE)
+    if (BOOST_LIKELY(size > 0 && size <= static_cast< uintmax_t >((std::numeric_limits< off_t >::max)())))
+    {
+        while (true)
+        {
+            // Note: We intentionally use fallocate rather than posix_fallocate to avoid
+            //       invoking glibc emulation that writes zeros to the end of the file.
+            //       We want this call to act like a hint to the filesystem and an early
+            //       check for the free storage space. We don't want to write zeros only
+            //       to later overwrite them with the actual data.
+            int err = fallocate(file, FALLOC_FL_KEEP_SIZE, 0, static_cast< off_t >(size));
+            if (BOOST_UNLIKELY(err != 0))
+            {
+                err = errno;
+
+                // Ignore the error if the operation is not supported by the kernel or filesystem
+                if (err == EOPNOTSUPP || err == ENOSYS)
+                    break;
+
+                if (err == EINTR)
+                    continue;
+
+                return err;
+            }
+
+            break;
+        }
+    }
+#endif
+
+    return 0;
+}
+
+//! copy_file implementation wrapper that preallocates storage for the target file
+template< typename CopyFileData >
+struct copy_file_data_preallocate
+{
+    //! copy_file implementation wrapper that preallocates storage for the target file before invoking the underlying copy implementation
+    static int impl(int infile, int outfile, uintmax_t size, std::size_t blksize)
+    {
+        int err = preallocate_storage(outfile, size);
+        if (BOOST_UNLIKELY(err != 0))
+            return err;
+
+        return CopyFileData::impl(infile, outfile, size, blksize);
+    }
+};
+
+// Min and max buffer sizes are selected to minimize the overhead from system calls.
+// The values are picked based on coreutils cp(1) benchmarking data described here:
+// https://github.com/coreutils/coreutils/blob/d1b0257077c0b0f0ee25087efd46270345d1dd1f/src/ioblksize.h#L23-L72
+BOOST_CONSTEXPR_OR_CONST uint_least32_t min_read_write_buf_size = 8u * 1024u;
+BOOST_CONSTEXPR_OR_CONST uint_least32_t max_read_write_buf_size = 256u * 1024u;
+
+//! copy_file read/write loop implementation
+int copy_file_data_read_write_impl(int infile, int outfile, char* buf, std::size_t buf_size)
+{
+#if defined(BOOST_FILESYSTEM_HAS_POSIX_FADVISE)
+    ::posix_fadvise(infile, 0, 0, POSIX_FADV_SEQUENTIAL);
+#endif
+
+    // Don't use file size to limit the amount of data to copy since some filesystems, like procfs or sysfs,
+    // provide files with generated content and indicate that their size is zero or 4096. Just copy as much data
+    // as we can read from the input file.
+    while (true)
+    {
+        ssize_t sz_read = ::read(infile, buf, buf_size);
+        if (sz_read == 0)
+            break;
+        if (BOOST_UNLIKELY(sz_read < 0))
+        {
+            int err = errno;
+            if (err == EINTR)
+                continue;
+            return err;
+        }
+
+        // Allow for partial writes - see Advanced Unix Programming (2nd Ed.),
+        // Marc Rochkind, Addison-Wesley, 2004, page 94
+        for (ssize_t sz_wrote = 0; sz_wrote < sz_read;)
+        {
+            ssize_t sz = ::write(outfile, buf + sz_wrote, static_cast< std::size_t >(sz_read - sz_wrote));
+            if (BOOST_UNLIKELY(sz < 0))
+            {
+                int err = errno;
+                if (err == EINTR)
+                    continue;
+                return err;
+            }
+
+            sz_wrote += sz;
+        }
+    }
+
+    return 0;
+}
+
+//! copy_file implementation that uses read/write loop (fallback using a stack buffer)
+int copy_file_data_read_write_stack_buf(int infile, int outfile)
+{
+    char stack_buf[min_read_write_buf_size];
+    return copy_file_data_read_write_impl(infile, outfile, stack_buf, sizeof(stack_buf));
+}
+
+//! copy_file implementation that uses read/write loop
+int copy_file_data_read_write(int infile, int outfile, uintmax_t size, std::size_t blksize)
+{
+    {
+        uintmax_t buf_sz = size;
+        // Prefer the buffer to be larger than the file size so that we don't have
+        // to perform an extra read if the file fits in the buffer exactly.
+        buf_sz += (buf_sz < ~static_cast< uintmax_t >(0u));
+        if (buf_sz < blksize)
+            buf_sz = blksize;
+        if (buf_sz < min_read_write_buf_size)
+            buf_sz = min_read_write_buf_size;
+        if (buf_sz > max_read_write_buf_size)
+            buf_sz = max_read_write_buf_size;
+        const std::size_t buf_size = static_cast< std::size_t >(boost::core::bit_ceil(static_cast< uint_least32_t >(buf_sz)));
+        std::unique_ptr< char[] > buf(new (std::nothrow) char[buf_size]);
+        if (BOOST_LIKELY(!!buf.get()))
+            return copy_file_data_read_write_impl(infile, outfile, buf.get(), buf_size);
+    }
+
+    return copy_file_data_read_write_stack_buf(infile, outfile);
+}
+
+typedef int copy_file_data_t(int infile, int outfile, uintmax_t size, std::size_t blksize);
+
+//! Pointer to the actual implementation of the copy_file_data implementation
+copy_file_data_t* copy_file_data = &copy_file_data_read_write;
+
+#if defined(BOOST_FILESYSTEM_USE_SENDFILE) || defined(BOOST_FILESYSTEM_USE_COPY_FILE_RANGE)
+
+//! copy_file_data wrapper that tests if a read/write loop must be used for a given filesystem
+template< typename CopyFileData >
+int check_fs_type(int infile, int outfile, uintmax_t size, std::size_t blksize);
+
+#endif // defined(BOOST_FILESYSTEM_USE_SENDFILE) || defined(BOOST_FILESYSTEM_USE_COPY_FILE_RANGE)
+
+#if defined(BOOST_FILESYSTEM_USE_SENDFILE)
+
+struct copy_file_data_sendfile
+{
+    //! copy_file implementation that uses sendfile loop. Requires sendfile to support file descriptors.
+    static int impl(int infile, int outfile, uintmax_t size, std::size_t blksize)
+    {
+        // sendfile will not send more than this amount of data in one call
+        BOOST_CONSTEXPR_OR_CONST std::size_t max_batch_size = 0x7ffff000u;
+        uintmax_t offset = 0u;
+        while (offset < size)
+        {
+            uintmax_t size_left = size - offset;
+            std::size_t size_to_copy = max_batch_size;
+            if (size_left < static_cast< uintmax_t >(max_batch_size))
+                size_to_copy = static_cast< std::size_t >(size_left);
+            ssize_t sz = ::sendfile(outfile, infile, nullptr, size_to_copy);
+            if (BOOST_LIKELY(sz > 0))
+            {
+                offset += sz;
+            }
+            else if (sz < 0)
+            {
+                int err = errno;
+                if (err == EINTR)
+                    continue;
+
+                if (offset == 0u)
+                {
+                    // sendfile may fail with EINVAL if the underlying filesystem does not support it
+                    if (err == EINVAL)
+                    {
+                    fallback_to_read_write:
+                        return copy_file_data_read_write(infile, outfile, size, blksize);
+                    }
+
+                    if (err == ENOSYS)
+                    {
+                        filesystem::detail::atomic_store_relaxed(copy_file_data, &copy_file_data_read_write);
+                        goto fallback_to_read_write;
+                    }
+                }
+
+                return err;
+            }
+            else
+            {
+                // EOF: the input file was truncated while copying was in progress
+                break;
+            }
+        }
+
+        return 0;
+    }
+};
+
+#endif // defined(BOOST_FILESYSTEM_USE_SENDFILE)
+
+#if defined(BOOST_FILESYSTEM_USE_COPY_FILE_RANGE)
+
+struct copy_file_data_copy_file_range
+{
+    //! copy_file implementation that uses copy_file_range loop. Requires copy_file_range to support cross-filesystem copying.
+    static int impl(int infile, int outfile, uintmax_t size, std::size_t blksize)
+    {
+        // Although copy_file_range does not document any particular upper limit of one transfer, still use some upper bound to guarantee
+        // that size_t is not overflown in case if off_t is larger and the file size does not fit in size_t.
+        BOOST_CONSTEXPR_OR_CONST std::size_t max_batch_size = 0x7ffff000u;
+        uintmax_t offset = 0u;
+        while (offset < size)
+        {
+            uintmax_t size_left = size - offset;
+            std::size_t size_to_copy = max_batch_size;
+            if (size_left < static_cast< uintmax_t >(max_batch_size))
+                size_to_copy = static_cast< std::size_t >(size_left);
+            // Note: Use syscall directly to avoid depending on libc version. copy_file_range is added in glibc 2.27.
+            // uClibc-ng does not have copy_file_range as of the time of this writing (the latest uClibc-ng release is 1.0.33).
+            loff_t sz = ::syscall(__NR_copy_file_range, infile, (loff_t*)nullptr, outfile, (loff_t*)nullptr, size_to_copy, (unsigned int)0u);
+            if (BOOST_LIKELY(sz > 0))
+            {
+                offset += sz;
+            }
+            else if (sz < 0)
+            {
+                int err = errno;
+                if (err == EINTR)
+                    continue;
+
+                if (offset == 0u)
+                {
+                    // copy_file_range may fail with EINVAL if the underlying filesystem does not support it.
+                    // In some RHEL/CentOS 7.7-7.8 kernel versions, copy_file_range on NFSv4 is also known to return EOPNOTSUPP
+                    // if the remote server does not support COPY, despite that it is not a documented error code.
+                    // See https://patchwork.kernel.org/project/linux-nfs/patch/20190411183418.4510-1-olga.kornievskaia@gmail.com/
+                    // and https://bugzilla.redhat.com/show_bug.cgi?id=1783554.
+                    if (err == EINVAL || err == EOPNOTSUPP)
+                    {
+#if !defined(BOOST_FILESYSTEM_USE_SENDFILE)
+                    fallback_to_read_write:
+#endif
+                        return copy_file_data_read_write(infile, outfile, size, blksize);
+                    }
+
+                    if (err == EXDEV)
+                    {
+#if defined(BOOST_FILESYSTEM_USE_SENDFILE)
+                    fallback_to_sendfile:
+                        return copy_file_data_sendfile::impl(infile, outfile, size, blksize);
+#else
+                        goto fallback_to_read_write;
+#endif
+                    }
+
+                    if (err == ENOSYS)
+                    {
+#if defined(BOOST_FILESYSTEM_USE_SENDFILE)
+                        filesystem::detail::atomic_store_relaxed(copy_file_data, &check_fs_type< copy_file_data_preallocate< copy_file_data_sendfile > >);
+                        goto fallback_to_sendfile;
+#else
+                        filesystem::detail::atomic_store_relaxed(copy_file_data, &copy_file_data_read_write);
+                        goto fallback_to_read_write;
+#endif
+                    }
+                }
+
+                return err;
+            }
+            else
+            {
+                // EOF: the input file was truncated while copying was in progress
+                break;
+            }
+        }
+
+        return 0;
+    }
+};
+
+#endif // defined(BOOST_FILESYSTEM_USE_COPY_FILE_RANGE)
+
+#if defined(BOOST_FILESYSTEM_USE_SENDFILE) || defined(BOOST_FILESYSTEM_USE_COPY_FILE_RANGE)
+
+//! copy_file_data wrapper that tests if a read/write loop must be used for a given filesystem
+template< typename CopyFileData >
+int check_fs_type(int infile, int outfile, uintmax_t size, std::size_t blksize)
+{
+    {
+        // Some filesystems have regular files with generated content. Such files have arbitrary size, including zero,
+        // but have actual content. Linux system calls sendfile or copy_file_range will not copy contents of such files,
+        // so we must use a read/write loop to handle them.
+        // https://lore.kernel.org/linux-fsdevel/20210212044405.4120619-1-drinkcat@chromium.org/T/
+        struct statfs sfs;
+        while (true)
+        {
+            int err = ::fstatfs(infile, &sfs);
+            if (BOOST_UNLIKELY(err < 0))
+            {
+                err = errno;
+                if (err == EINTR)
+                    continue;
+
+                goto fallback_to_read_write;
+            }
+
+            break;
+        }
+
+        if (BOOST_UNLIKELY(sfs.f_type == PROC_SUPER_MAGIC ||
+            sfs.f_type == SYSFS_MAGIC ||
+            sfs.f_type == TRACEFS_MAGIC ||
+            sfs.f_type == DEBUGFS_MAGIC))
+        {
+        fallback_to_read_write:
+            return copy_file_data_read_write(infile, outfile, size, blksize);
+        }
+    }
+
+    return CopyFileData::impl(infile, outfile, size, blksize);
+}
+
+#endif // defined(BOOST_FILESYSTEM_USE_SENDFILE) || defined(BOOST_FILESYSTEM_USE_COPY_FILE_RANGE)
+
+#if defined(linux) || defined(__linux) || defined(__linux__)
+
+//! Initializes copy_file_data implementation pointer
+inline void init_copy_file_data_impl(unsigned int major_ver, unsigned int minor_ver, unsigned int patch_ver)
+{
+#if defined(BOOST_FILESYSTEM_USE_SENDFILE) || defined(BOOST_FILESYSTEM_USE_COPY_FILE_RANGE)
+    copy_file_data_t* cfd = &copy_file_data_read_write;
+
+#if defined(BOOST_FILESYSTEM_USE_SENDFILE)
+    // sendfile started accepting file descriptors as the target in Linux 2.6.33
+    if (major_ver > 2u || (major_ver == 2u && (minor_ver > 6u || (minor_ver == 6u && patch_ver >= 33u))))
+        cfd = &check_fs_type< copy_file_data_preallocate< copy_file_data_sendfile > >;
+#endif
+
+#if defined(BOOST_FILESYSTEM_USE_COPY_FILE_RANGE)
+    // Although copy_file_range appeared in Linux 4.5, it did not support cross-filesystem copying until 5.3.
+    // copy_file_data_copy_file_range will fallback to copy_file_data_sendfile if copy_file_range returns EXDEV.
+    if (major_ver > 4u || (major_ver == 4u && minor_ver >= 5u))
+        cfd = &check_fs_type< copy_file_data_preallocate< copy_file_data_copy_file_range > >;
+#endif
+
+    filesystem::detail::atomic_store_relaxed(copy_file_data, cfd);
+#endif // defined(BOOST_FILESYSTEM_USE_SENDFILE) || defined(BOOST_FILESYSTEM_USE_COPY_FILE_RANGE)
+}
+
+#endif // defined(linux) || defined(__linux) || defined(__linux__)
+
+#if defined(linux) || defined(__linux) || defined(__linux__)
+
+struct syscall_initializer
+{
+    syscall_initializer()
+    {
+        struct ::utsname system_info;
+        if (BOOST_UNLIKELY(::uname(&system_info) < 0))
+            return;
+
+        unsigned int major_ver = 0u, minor_ver = 0u, patch_ver = 0u;
+        int count = std::sscanf(system_info.release, "%u.%u.%u", &major_ver, &minor_ver, &patch_ver);
+        if (BOOST_UNLIKELY(count < 3))
+            return;
+
+        init_statx_impl(major_ver, minor_ver, patch_ver);
+        init_copy_file_data_impl(major_ver, minor_ver, patch_ver);
+        init_fill_random_impl(major_ver, minor_ver, patch_ver);
+    }
+};
+
+BOOST_FILESYSTEM_INIT_PRIORITY(BOOST_FILESYSTEM_FUNC_PTR_INIT_PRIORITY) BOOST_ATTRIBUTE_UNUSED BOOST_FILESYSTEM_ATTRIBUTE_RETAIN
+const syscall_initializer syscall_init;
+
+#endif // defined(linux) || defined(__linux) || defined(__linux__)
+
+//! remove() implementation
+inline bool remove_impl
+(
+    path const& p,
+    fs::file_type type,
+    error_code* ec
+#if defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+    , int basedir_fd = AT_FDCWD
+#endif
+)
+{
+    if (type == fs::file_not_found)
+        return false;
+
+    int res;
+#if defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+    res = ::unlinkat(basedir_fd, p.c_str(), type == fs::directory_file ? AT_REMOVEDIR : 0);
+#else
+    if (type == fs::directory_file)
+        res = ::rmdir(p.c_str());
+    else
+        res = ::unlink(p.c_str());
+#endif
+
+    if (res != 0)
+    {
+        int err = errno;
+        if (BOOST_UNLIKELY(!not_found_error(err)))
+            emit_error(err, p, ec, "boost::filesystem::remove");
+
+        return false;
+    }
+
+    return true;
+}
+
+//! remove() implementation
+inline bool remove_impl(path const& p, error_code* ec)
+{
+    // Since POSIX remove() is specified to work with either files or directories, in a
+    // perfect world it could just be called. But some important real-world operating
+    // systems (Windows, Mac OS, for example) don't implement the POSIX spec. So
+    // we have to distinguish between files and directories and call corresponding APIs
+    // to remove them.
+
+    error_code local_ec;
+    fs::file_type type = fs::detail::symlink_status_impl(p, &local_ec).type();
+    if (BOOST_UNLIKELY(type == fs::status_error))
+    {
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::remove", p, local_ec));
+
+        *ec = local_ec;
+        return false;
+    }
+
+    return fs::detail::remove_impl(p, type, ec);
+}
+
+//! remove_all() implementation
+uintmax_t remove_all_impl
+(
+    path const& p,
+    error_code* ec
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+    , int parentdir_fd = AT_FDCWD
+#endif
+)
+{
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+    fs::path filename;
+    const fs::path* remove_path = &p;
+    if (parentdir_fd != AT_FDCWD)
+    {
+        filename = path_algorithms::filename_v4(p);
+        remove_path = &filename;
+    }
+#endif
+
+    error_code dit_create_ec;
+    for (unsigned int attempt = 0u; attempt < remove_all_directory_replaced_retry_count; ++attempt)
+    {
+        fs::file_type type;
+        {
+            error_code local_ec;
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+            type = fs::detail::symlink_status_impl(*remove_path, &local_ec, parentdir_fd).type();
+#else
+            type = fs::detail::symlink_status_impl(p, &local_ec).type();
+#endif
+
+            if (type == fs::file_not_found)
+                return 0u;
+
+            if (BOOST_UNLIKELY(type == fs::status_error))
+            {
+                if (!ec)
+                    BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::remove_all", p, local_ec));
+
+                *ec = local_ec;
+                return static_cast< uintmax_t >(-1);
+            }
+        }
+
+        uintmax_t count = 0u;
+        if (type == fs::directory_file) // but not a directory symlink
+        {
+            fs::directory_iterator itr;
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+            fs::detail::directory_iterator_params params{ fs::detail::openat_directory(parentdir_fd, *remove_path, directory_options::_detail_no_follow, dit_create_ec) };
+            int dir_fd = -1;
+            if (BOOST_LIKELY(!dit_create_ec))
+            {
+                // Save dir_fd as constructing the iterator will move the fd into the iterator context
+                dir_fd = params.dir_fd.get();
+                fs::detail::directory_iterator_construct(itr, *remove_path, directory_options::_detail_no_follow, &params, &dit_create_ec);
+            }
+#else
+            fs::detail::directory_iterator_construct
+            (
+                itr,
+                p,
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+                directory_options::_detail_no_follow,
+#else
+                directory_options::none,
+#endif
+                nullptr,
+                &dit_create_ec
+            );
+#endif
+
+            if (BOOST_UNLIKELY(!!dit_create_ec))
+            {
+                if (dit_create_ec == error_code(ENOTDIR, system_category()))
+                    continue;
+
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+                // If open(2) with O_NOFOLLOW fails with ELOOP, this means that either the path contains a loop
+                // of symbolic links, or the last element of the path is a symbolic link. Given that lstat(2) above
+                // did not fail, most likely it is the latter case. I.e. between the lstat above and this open call
+                // the filesystem was modified so that the path no longer refers to a directory file (as opposed to a symlink).
+                if (dit_create_ec == error_code(ELOOP, system_category()))
+                    continue;
+#endif // defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+
+                if (!ec)
+                    BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::remove_all", p, dit_create_ec));
+
+                *ec = dit_create_ec;
+                return static_cast< uintmax_t >(-1);
+            }
+
+            const fs::directory_iterator end_dit;
+            while (itr != end_dit)
+            {
+                count += fs::detail::remove_all_impl
+                (
+                    itr->path(),
+                    ec
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+                    , dir_fd
+#endif
+                );
+                if (ec && *ec)
+                    return static_cast< uintmax_t >(-1);
+
+                fs::detail::directory_iterator_increment(itr, ec);
+                if (ec && *ec)
+                    return static_cast< uintmax_t >(-1);
+            }
+        }
+
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW) && defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+        count += fs::detail::remove_impl(*remove_path, type, ec, parentdir_fd);
+#else
+        count += fs::detail::remove_impl(p, type, ec);
+#endif
+        if (ec && *ec)
+            return static_cast< uintmax_t >(-1);
+
+        return count;
+    }
+
+    if (!ec)
+        BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::remove_all: path cannot be opened as a directory", p, dit_create_ec));
+
+    *ec = dit_create_ec;
+    return static_cast< uintmax_t >(-1);
+}
+
+#else // defined(BOOST_POSIX_API)
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//                            Windows-specific helpers                                  //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+//! FILE_BASIC_INFO definition from Windows SDK
+struct file_basic_info
+{
+    LARGE_INTEGER CreationTime;
+    LARGE_INTEGER LastAccessTime;
+    LARGE_INTEGER LastWriteTime;
+    LARGE_INTEGER ChangeTime;
+    DWORD FileAttributes;
+};
+
+//! FILE_DISPOSITION_INFO definition from Windows SDK
+struct file_disposition_info
+{
+    BOOLEAN DeleteFile;
+};
+
+//! FILE_DISPOSITION_INFO_EX definition from Windows SDK
+struct file_disposition_info_ex
+{
+    DWORD Flags;
+};
+
+#ifndef FILE_DISPOSITION_FLAG_DELETE
+#define FILE_DISPOSITION_FLAG_DELETE 0x00000001
+#endif
+// Available since Windows 10 1709
+#ifndef FILE_DISPOSITION_FLAG_POSIX_SEMANTICS
+#define FILE_DISPOSITION_FLAG_POSIX_SEMANTICS 0x00000002
+#endif
+// Available since Windows 10 1809
+#ifndef FILE_DISPOSITION_FLAG_IGNORE_READONLY_ATTRIBUTE
+#define FILE_DISPOSITION_FLAG_IGNORE_READONLY_ATTRIBUTE 0x00000010
+#endif
+
+//  REPARSE_DATA_BUFFER related definitions are found in ntifs.h, which is part of the
+//  Windows Device Driver Kit. Since that's inconvenient, the definitions are provided
+//  here. See http://msdn.microsoft.com/en-us/library/ms791514.aspx
+struct reparse_data_buffer
+{
+    ULONG ReparseTag;
+    USHORT ReparseDataLength;
+    USHORT Reserved;
+    union
+    {
+        /*
+         * In SymbolicLink and MountPoint reparse points, there are two names.
+         * SubstituteName is the effective replacement path for the reparse point.
+         * This is what should be used for path traversal.
+         * PrintName is intended for presentation to the user and may omit some
+         * elements of the path or be absent entirely.
+         *
+         * Examples of substitute and print names:
+         * mklink /D ldrive c:\
+         * SubstituteName: "\??\c:\"
+         * PrintName: "c:\"
+         *
+         * mklink /J ldrive c:\
+         * SubstituteName: "\??\C:\"
+         * PrintName: "c:\"
+         *
+         * junction ldrive c:\
+         * SubstituteName: "\??\C:\"
+         * PrintName: ""
+         *
+         * box.com mounted cloud storage
+         * SubstituteName: "\??\Volume{<UUID>}\"
+         * PrintName: ""
+         */
+        struct
+        {
+            USHORT SubstituteNameOffset;
+            USHORT SubstituteNameLength;
+            USHORT PrintNameOffset;
+            USHORT PrintNameLength;
+            ULONG Flags;
+            WCHAR PathBuffer[1];
+        } SymbolicLinkReparseBuffer;
+        struct
+        {
+            USHORT SubstituteNameOffset;
+            USHORT SubstituteNameLength;
+            USHORT PrintNameOffset;
+            USHORT PrintNameLength;
+            WCHAR PathBuffer[1];
+        } MountPointReparseBuffer;
+        struct
+        {
+            UCHAR DataBuffer[1];
+        } GenericReparseBuffer;
+    };
+};
+
+// Our convenience type for allocating REPARSE_DATA_BUFFER along with sufficient space after it
+union reparse_data_buffer_with_storage
+{
+    reparse_data_buffer rdb;
+    unsigned char storage[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
+};
+
+//  Windows kernel32.dll functions that may or may not be present
+//  must be accessed through pointers
+
+typedef BOOL (WINAPI CreateHardLinkW_t)(
+    /*__in*/ LPCWSTR lpFileName,
+    /*__in*/ LPCWSTR lpExistingFileName,
+    /*__reserved*/ LPSECURITY_ATTRIBUTES lpSecurityAttributes);
+
+CreateHardLinkW_t* create_hard_link_api = nullptr;
+
+typedef BOOLEAN (WINAPI CreateSymbolicLinkW_t)(
+    /*__in*/ LPCWSTR lpSymlinkFileName,
+    /*__in*/ LPCWSTR lpTargetFileName,
+    /*__in*/ DWORD dwFlags);
+
+CreateSymbolicLinkW_t* create_symbolic_link_api = nullptr;
+
+//! SetFileInformationByHandle signature. Available since Windows Vista.
+typedef BOOL (WINAPI SetFileInformationByHandle_t)(
+    /*_In_*/ HANDLE hFile,
+    /*_In_*/ file_info_by_handle_class FileInformationClass, // the actual type is FILE_INFO_BY_HANDLE_CLASS enum
+    /*_In_reads_bytes_(dwBufferSize)*/ LPVOID lpFileInformation,
+    /*_In_*/ DWORD dwBufferSize);
+
+SetFileInformationByHandle_t* set_file_information_by_handle_api = nullptr;
+
+} // unnamed namespace
+
+GetFileInformationByHandleEx_t* get_file_information_by_handle_ex_api = nullptr;
+
+NtCreateFile_t* nt_create_file_api = nullptr;
+NtQueryDirectoryFile_t* nt_query_directory_file_api = nullptr;
+
+namespace {
+
+//! remove() implementation type
+enum remove_impl_type
+{
+    remove_nt5,                            //!< Use Windows XP API
+    remove_disp,                           //!< Use FILE_DISPOSITION_INFO (Windows Vista and later)
+    remove_disp_ex_flag_posix_semantics,   //!< Use FILE_DISPOSITION_INFO_EX with FILE_DISPOSITION_FLAG_POSIX_SEMANTICS
+    remove_disp_ex_flag_ignore_readonly    //!< Use FILE_DISPOSITION_INFO_EX with FILE_DISPOSITION_FLAG_POSIX_SEMANTICS | FILE_DISPOSITION_FLAG_IGNORE_READONLY_ATTRIBUTE
+};
+
+remove_impl_type g_remove_impl_type = remove_nt5;
+
+//! Initializes WinAPI function pointers
+BOOST_FILESYSTEM_INIT_FUNC init_winapi_func_ptrs()
+{
+    boost::winapi::HMODULE_ h = boost::winapi::GetModuleHandleW(L"kernel32.dll");
+    if (BOOST_LIKELY(!!h))
+    {
+        GetFileInformationByHandleEx_t* get_file_information_by_handle_ex = (GetFileInformationByHandleEx_t*)boost::winapi::get_proc_address(h, "GetFileInformationByHandleEx");
+        filesystem::detail::atomic_store_relaxed(get_file_information_by_handle_ex_api, get_file_information_by_handle_ex);
+        SetFileInformationByHandle_t* set_file_information_by_handle = (SetFileInformationByHandle_t*)boost::winapi::get_proc_address(h, "SetFileInformationByHandle");
+        filesystem::detail::atomic_store_relaxed(set_file_information_by_handle_api, set_file_information_by_handle);
+        filesystem::detail::atomic_store_relaxed(create_hard_link_api, (CreateHardLinkW_t*)boost::winapi::get_proc_address(h, "CreateHardLinkW"));
+        filesystem::detail::atomic_store_relaxed(create_symbolic_link_api, (CreateSymbolicLinkW_t*)boost::winapi::get_proc_address(h, "CreateSymbolicLinkW"));
+
+        if (get_file_information_by_handle_ex && set_file_information_by_handle)
+        {
+            // Enable the most advanced implementation based on GetFileInformationByHandleEx/SetFileInformationByHandle.
+            // If certain flags are not supported by the OS, the remove() implementation will downgrade accordingly.
+            filesystem::detail::atomic_store_relaxed(g_remove_impl_type, remove_disp_ex_flag_ignore_readonly);
+        }
+    }
+
+    h = boost::winapi::GetModuleHandleW(L"ntdll.dll");
+    if (BOOST_LIKELY(!!h))
+    {
+        filesystem::detail::atomic_store_relaxed(nt_create_file_api, (NtCreateFile_t*)boost::winapi::get_proc_address(h, "NtCreateFile"));
+        filesystem::detail::atomic_store_relaxed(nt_query_directory_file_api, (NtQueryDirectoryFile_t*)boost::winapi::get_proc_address(h, "NtQueryDirectoryFile"));
+    }
+
+    init_directory_iterator_impl();
+
+    return BOOST_FILESYSTEM_INITRETSUCCESS_V;
+}
+
+#if defined(_MSC_VER)
+
+#if _MSC_VER >= 1400
+
+#pragma section(".CRT$XCL", long, read)
+__declspec(allocate(".CRT$XCL")) BOOST_ATTRIBUTE_UNUSED BOOST_FILESYSTEM_ATTRIBUTE_RETAIN
+extern const init_func_ptr_t p_init_winapi_func_ptrs = &init_winapi_func_ptrs;
+
+#else // _MSC_VER >= 1400
+
+#if (_MSC_VER >= 1300) // 1300 == VC++ 7.0
+#pragma data_seg(push, old_seg)
+#endif
+#pragma data_seg(".CRT$XCL")
+BOOST_ATTRIBUTE_UNUSED BOOST_FILESYSTEM_ATTRIBUTE_RETAIN
+extern const init_func_ptr_t p_init_winapi_func_ptrs = &init_winapi_func_ptrs;
+#pragma data_seg()
+#if (_MSC_VER >= 1300) // 1300 == VC++ 7.0
+#pragma data_seg(pop, old_seg)
+#endif
+
+#endif // _MSC_VER >= 1400
+
+#if defined(BOOST_FILESYSTEM_NO_ATTRIBUTE_RETAIN)
+//! Makes sure the global initializer pointers are referenced and not removed by linker
+struct globals_retainer
+{
+    const init_func_ptr_t* volatile m_p_init_winapi_func_ptrs;
+
+    globals_retainer() { m_p_init_winapi_func_ptrs = &p_init_winapi_func_ptrs; }
+};
+BOOST_ATTRIBUTE_UNUSED
+const globals_retainer g_globals_retainer;
+#endif // defined(BOOST_FILESYSTEM_NO_ATTRIBUTE_RETAIN)
+
+#else // defined(_MSC_VER)
+
+//! Invokes WinAPI function pointers initialization
+struct winapi_func_ptrs_initializer
+{
+    winapi_func_ptrs_initializer() { init_winapi_func_ptrs(); }
+};
+
+BOOST_FILESYSTEM_INIT_PRIORITY(BOOST_FILESYSTEM_FUNC_PTR_INIT_PRIORITY) BOOST_ATTRIBUTE_UNUSED BOOST_FILESYSTEM_ATTRIBUTE_RETAIN
+const winapi_func_ptrs_initializer winapi_func_ptrs_init;
+
+#endif // defined(_MSC_VER)
+
+
+inline std::wstring wgetenv(const wchar_t* name)
+{
+    // use a separate buffer since C++03 basic_string is not required to be contiguous
+    const DWORD size = ::GetEnvironmentVariableW(name, nullptr, 0);
+    if (size > 0)
+    {
+        std::unique_ptr< wchar_t[] > buf(new wchar_t[size]);
+        if (BOOST_LIKELY(::GetEnvironmentVariableW(name, buf.get(), size) > 0))
+            return std::wstring(buf.get());
+    }
+
+    return std::wstring();
+}
+
+inline bool not_found_error(int errval) noexcept
+{
+    return errval == ERROR_FILE_NOT_FOUND || errval == ERROR_PATH_NOT_FOUND || errval == ERROR_INVALID_NAME // "tools/jam/src/:sys:stat.h", "//foo"
+        || errval == ERROR_INVALID_DRIVE                                                                    // USB card reader with no card inserted
+        || errval == ERROR_NOT_READY                                                                        // CD/DVD drive with no disc inserted
+        || errval == ERROR_INVALID_PARAMETER                                                                // ":sys:stat.h"
+        || errval == ERROR_BAD_PATHNAME                                                                     // "//no-host" on Win64
+        || errval == ERROR_BAD_NETPATH                                                                      // "//no-host" on Win32
+        || errval == ERROR_BAD_NET_NAME;                                                                    // "//no-host/no-share" on Win10 x64
+}
+
+// these constants come from inspecting some Microsoft sample code
+inline DWORD to_time_t(FILETIME const& ft, std::time_t& t)
+{
+    uint64_t ut = (static_cast< uint64_t >(ft.dwHighDateTime) << 32u) | ft.dwLowDateTime;
+    if (BOOST_UNLIKELY(ut > static_cast< uint64_t >((std::numeric_limits< int64_t >::max)())))
+        return ERROR_INVALID_DATA;
+
+    // On Windows, time_t is signed, and negative values are possible since FILETIME epoch is earlier than POSIX epoch
+    int64_t st = static_cast< int64_t >(ut) / 10000000 - 11644473600ll;
+    if (BOOST_UNLIKELY(st < static_cast< int64_t >((std::numeric_limits< std::time_t >::min)()) ||
+        st > static_cast< int64_t >((std::numeric_limits< std::time_t >::max)())))
+    {
+        return ERROR_INVALID_DATA;
+    }
+
+    t = static_cast< std::time_t >(st);
+    return 0u;
+}
+
+inline DWORD to_FILETIME(std::time_t t, FILETIME& ft)
+{
+    // On Windows, time_t is signed, and negative values are possible since FILETIME epoch is earlier than POSIX epoch
+    int64_t st = static_cast< int64_t >(t);
+    if (BOOST_UNLIKELY(st < ((std::numeric_limits< int64_t >::min)() / 10000000 - 11644473600ll) ||
+        st > ((std::numeric_limits< int64_t >::max)() / 10000000 - 11644473600ll)))
+    {
+        return ERROR_INVALID_DATA;
+    }
+
+    st = (st + 11644473600ll) * 10000000;
+    uint64_t ut = static_cast< uint64_t >(st);
+    ft.dwLowDateTime = static_cast< DWORD >(ut);
+    ft.dwHighDateTime = static_cast< DWORD >(ut >> 32u);
+
+    return 0u;
+}
+
+} // unnamed namespace
+
+//! The flag indicates whether OBJ_DONT_REPARSE flag is not supported by the kernel
+static bool g_no_obj_dont_reparse = false;
+
+//! Creates a file handle for a file relative to a previously opened base directory. The file path must be relative and in preferred format.
+boost::winapi::NTSTATUS_ nt_create_file_handle_at
+(
+    unique_handle& out,
+    HANDLE basedir_handle,
+    boost::filesystem::path const& p,
+    ULONG FileAttributes,
+    ACCESS_MASK DesiredAccess,
+    ULONG ShareMode,
+    ULONG CreateDisposition,
+    ULONG CreateOptions
+)
+{
+    NtCreateFile_t* nt_create_file = filesystem::detail::atomic_load_relaxed(nt_create_file_api);
+    if (BOOST_UNLIKELY(!nt_create_file))
+        return STATUS_NOT_IMPLEMENTED;
+
+    unicode_string obj_name = {};
+    obj_name.Buffer = const_cast< wchar_t* >(p.c_str());
+    obj_name.Length = obj_name.MaximumLength = static_cast< USHORT >(p.size() * sizeof(wchar_t));
+
+    object_attributes obj_attrs = {};
+    obj_attrs.Length = sizeof(obj_attrs);
+    obj_attrs.RootDirectory = basedir_handle;
+    obj_attrs.ObjectName = &obj_name;
+
+    obj_attrs.Attributes = OBJ_CASE_INSENSITIVE;
+    if ((CreateOptions & FILE_OPEN_REPARSE_POINT) != 0u && !filesystem::detail::atomic_load_relaxed(g_no_obj_dont_reparse))
+        obj_attrs.Attributes |= OBJ_DONT_REPARSE;
+
+    io_status_block iosb;
+    HANDLE out_handle = INVALID_HANDLE_VALUE;
+    boost::winapi::NTSTATUS_ status = nt_create_file
+    (
+        &out_handle,
+        DesiredAccess,
+        &obj_attrs,
+        &iosb,
+        nullptr, // AllocationSize
+        FileAttributes,
+        ShareMode,
+        CreateDisposition,
+        CreateOptions,
+        nullptr, // EaBuffer
+        0u // EaLength
+    );
+
+    if (BOOST_UNLIKELY(status == STATUS_INVALID_PARAMETER && (obj_attrs.Attributes & OBJ_DONT_REPARSE) != 0u))
+    {
+        // OBJ_DONT_REPARSE is supported since Windows 10, retry without it
+        filesystem::detail::atomic_store_relaxed(g_no_obj_dont_reparse, true);
+        obj_attrs.Attributes &= ~static_cast< ULONG >(OBJ_DONT_REPARSE);
+
+        status = nt_create_file
+        (
+            &out_handle,
+            DesiredAccess,
+            &obj_attrs,
+            &iosb,
+            nullptr, // AllocationSize
+            FileAttributes,
+            ShareMode,
+            CreateDisposition,
+            CreateOptions,
+            nullptr, // EaBuffer
+            0u // EaLength
+        );
+    }
+
+    out.reset(out_handle);
+
+    return status;
+}
+
+ULONG get_reparse_point_tag_ioctl(HANDLE h, path const& p, error_code* ec)
+{
+    std::unique_ptr< reparse_data_buffer_with_storage > buf(new (std::nothrow) reparse_data_buffer_with_storage);
+    if (BOOST_UNLIKELY(!buf.get()))
+    {
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("Cannot allocate memory to query reparse point", p, make_error_code(system::errc::not_enough_memory)));
+
+        *ec = make_error_code(system::errc::not_enough_memory);
+        return 0u;
+    }
+
+    // Query the reparse data
+    DWORD dwRetLen = 0u;
+    BOOL result = ::DeviceIoControl(h, FSCTL_GET_REPARSE_POINT, nullptr, 0, buf.get(), sizeof(*buf), &dwRetLen, nullptr);
+    if (BOOST_UNLIKELY(!result))
+    {
+        DWORD err = ::GetLastError();
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("Failed to query reparse point", p, error_code(err, system_category())));
+
+        ec->assign(err, system_category());
+        return 0u;
+    }
+
+    return buf->rdb.ReparseTag;
+}
+
+namespace {
+
+inline std::size_t get_full_path_name(path const& src, std::size_t len, wchar_t* buf, wchar_t** p)
+{
+    return static_cast< std::size_t >(::GetFullPathNameW(src.c_str(), static_cast< DWORD >(len), buf, p));
+}
+
+inline fs::file_status process_status_failure(DWORD errval, path const& p, error_code* ec)
+{
+    if (ec)                                    // always report errval, even though some
+        ec->assign(errval, system_category()); // errval values are not status_errors
+
+    if (not_found_error(errval))
+    {
+        return fs::file_status(fs::file_not_found, fs::no_perms);
+    }
+    else if (errval == ERROR_SHARING_VIOLATION)
+    {
+        return fs::file_status(fs::type_unknown);
+    }
+
+    if (!ec)
+        BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::status", p, error_code(errval, system_category())));
+
+    return fs::file_status(fs::status_error);
+}
+
+inline fs::file_status process_status_failure(path const& p, error_code* ec)
+{
+    return process_status_failure(::GetLastError(), p, ec);
+}
+
+} // namespace
+
+//! (symlink_)status() by handle implementation
+fs::file_status status_by_handle(HANDLE h, path const& p, error_code* ec)
+{
+    fs::file_type ftype;
+    DWORD attrs;
+    ULONG reparse_tag = 0u;
+    GetFileInformationByHandleEx_t* get_file_information_by_handle_ex = filesystem::detail::atomic_load_relaxed(get_file_information_by_handle_ex_api);
+    if (BOOST_LIKELY(get_file_information_by_handle_ex != nullptr))
+    {
+        file_attribute_tag_info info;
+        BOOL res = get_file_information_by_handle_ex(h, file_attribute_tag_info_class, &info, sizeof(info));
+        if (BOOST_UNLIKELY(!res))
+        {
+            // On FAT/exFAT filesystems requesting FILE_ATTRIBUTE_TAG_INFO returns ERROR_INVALID_PARAMETER.
+            // Presumably, this is because these filesystems don't support reparse points, so ReparseTag
+            // cannot be returned. Also check ERROR_NOT_SUPPORTED for good measure. Fall back to the legacy
+            // code path in this case.
+            DWORD err = ::GetLastError();
+            if (err == ERROR_INVALID_PARAMETER || err == ERROR_NOT_SUPPORTED)
+                goto use_get_file_information_by_handle;
+
+            return process_status_failure(err, p, ec);
+        }
+
+        attrs = info.FileAttributes;
+        reparse_tag = info.ReparseTag;
+    }
+    else
+    {
+    use_get_file_information_by_handle:
+        BY_HANDLE_FILE_INFORMATION info;
+        BOOL res = ::GetFileInformationByHandle(h, &info);
+        if (BOOST_UNLIKELY(!res))
+            return process_status_failure(p, ec);
+
+        attrs = info.dwFileAttributes;
+
+        if ((attrs & FILE_ATTRIBUTE_REPARSE_POINT) != 0u)
+        {
+            reparse_tag = get_reparse_point_tag_ioctl(h, p, ec);
+            if (ec)
+            {
+                if (BOOST_UNLIKELY(!!ec))
+                    return fs::file_status(fs::status_error);
+            }
+        }
+    }
+
+    if ((attrs & FILE_ATTRIBUTE_REPARSE_POINT) != 0u)
+    {
+        if (reparse_tag == IO_REPARSE_TAG_DEDUP)
+            ftype = fs::regular_file;
+        else if (is_reparse_point_tag_a_symlink(reparse_tag))
+            ftype = fs::symlink_file;
+        else
+            ftype = fs::reparse_file;
+    }
+    else if ((attrs & FILE_ATTRIBUTE_DIRECTORY) != 0u)
+    {
+        ftype = fs::directory_file;
+    }
+    else
+    {
+        ftype = fs::regular_file;
+    }
+
+    return fs::file_status(ftype, make_permissions(p, attrs));
+}
+
+namespace {
+
+//! symlink_status() implementation
+fs::file_status symlink_status_impl(path const& p, error_code* ec)
+{
+    // Normally, we only need FILE_READ_ATTRIBUTES access mode. But SMBv1 reports incorrect
+    // file attributes in GetFileInformationByHandleEx in this case (e.g. it reports FILE_ATTRIBUTE_NORMAL
+    // for a directory in a SMBv1 share), so we add FILE_READ_EA as a workaround.
+    // https://github.com/boostorg/filesystem/issues/282
+    unique_handle h(create_file_handle(
+        p.c_str(),
+        FILE_READ_ATTRIBUTES | FILE_READ_EA,
+        FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+        nullptr, // lpSecurityAttributes
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT));
+
+    if (!h)
+    {
+        // For some system files and folders like "System Volume Information" CreateFileW fails
+        // with ERROR_ACCESS_DENIED. GetFileAttributesW succeeds for such files, so try that.
+        // Though this will only help if the file is not a reparse point (symlink or not).
+        DWORD err = ::GetLastError();
+        if (err == ERROR_ACCESS_DENIED)
+        {
+            DWORD attrs = ::GetFileAttributesW(p.c_str());
+            if (attrs != INVALID_FILE_ATTRIBUTES)
+            {
+                if ((attrs & FILE_ATTRIBUTE_REPARSE_POINT) == 0u)
+                    return fs::file_status((attrs & FILE_ATTRIBUTE_DIRECTORY) ? fs::directory_file : fs::regular_file, make_permissions(p, attrs));
+            }
+            else
+            {
+                err = ::GetLastError();
+            }
+        }
+
+        return process_status_failure(err, p, ec);
+    }
+
+    return detail::status_by_handle(h.get(), p, ec);
+}
+
+//! status() implementation
+fs::file_status status_impl(path const& p, error_code* ec)
+{
+    // We should first test if the file is a symlink or a reparse point. Resolving some reparse
+    // points by opening the file may fail, and status() should return file_status(reparse_file) in this case.
+    // Which is what symlink_status() returns.
+    fs::file_status st(detail::symlink_status_impl(p, ec));
+    if (st.type() == symlink_file)
+    {
+        // Resolve the symlink
+        unique_handle h(create_file_handle(
+            p.c_str(),
+            FILE_READ_ATTRIBUTES | FILE_READ_EA, // see the comment in symlink_status_impl re. access mode
+            FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+            nullptr, // lpSecurityAttributes
+            OPEN_EXISTING,
+            FILE_FLAG_BACKUP_SEMANTICS));
+
+        if (!h)
+            return process_status_failure(p, ec);
+
+        st = detail::status_by_handle(h.get(), p, ec);
+    }
+
+    return st;
+}
+
+//! remove() implementation for Windows XP and older
+bool remove_nt5_impl(path const& p, DWORD attrs, error_code* ec)
+{
+    const bool is_directory = (attrs & FILE_ATTRIBUTE_DIRECTORY) != 0;
+    const bool is_read_only = (attrs & FILE_ATTRIBUTE_READONLY) != 0;
+    if (is_read_only)
+    {
+        // RemoveDirectoryW and DeleteFileW do not allow to remove a read-only file, so we have to drop the attribute
+        DWORD new_attrs = attrs & ~FILE_ATTRIBUTE_READONLY;
+        BOOL res = ::SetFileAttributesW(p.c_str(), new_attrs);
+        if (BOOST_UNLIKELY(!res))
+        {
+            DWORD err = ::GetLastError();
+            if (!not_found_error(err))
+                emit_error(err, p, ec, "boost::filesystem::remove");
+
+            return false;
+        }
+    }
+
+    BOOL res;
+    if (!is_directory)
+    {
+        // DeleteFileW works for file symlinks by removing the symlink, not the target.
+        res = ::DeleteFileW(p.c_str());
+    }
+    else
+    {
+        // RemoveDirectoryW works for symlinks and junctions by removing the symlink, not the target,
+        // even if the target directory is not empty.
+        // Note that unlike opening the directory with FILE_FLAG_DELETE_ON_CLOSE flag, RemoveDirectoryW
+        // will fail if the directory is not empty.
+        res = ::RemoveDirectoryW(p.c_str());
+    }
+
+    if (BOOST_UNLIKELY(!res))
+    {
+        DWORD err = ::GetLastError();
+        if (!not_found_error(err))
+        {
+            if (is_read_only)
+            {
+                // Try to restore the read-only attribute
+                ::SetFileAttributesW(p.c_str(), attrs);
+            }
+
+            emit_error(err, p, ec, "boost::filesystem::remove");
+        }
+
+        return false;
+    }
+
+    return true;
+}
+
+//! remove() by handle implementation for Windows Vista and newer
+DWORD remove_nt6_by_handle(HANDLE handle, remove_impl_type impl)
+{
+    GetFileInformationByHandleEx_t* get_file_information_by_handle_ex = filesystem::detail::atomic_load_relaxed(get_file_information_by_handle_ex_api);
+    SetFileInformationByHandle_t* set_file_information_by_handle = filesystem::detail::atomic_load_relaxed(set_file_information_by_handle_api);
+    DWORD err = 0u;
+    switch (impl)
+    {
+    case remove_disp_ex_flag_ignore_readonly:
+        {
+            file_disposition_info_ex info;
+            info.Flags = FILE_DISPOSITION_FLAG_DELETE | FILE_DISPOSITION_FLAG_POSIX_SEMANTICS | FILE_DISPOSITION_FLAG_IGNORE_READONLY_ATTRIBUTE;
+            BOOL res = set_file_information_by_handle(handle, file_disposition_info_ex_class, &info, sizeof(info));
+            if (BOOST_LIKELY(!!res))
+                break;
+
+            err = ::GetLastError();
+            if (BOOST_UNLIKELY(err == ERROR_INVALID_PARAMETER || err == ERROR_INVALID_FUNCTION || err == ERROR_NOT_SUPPORTED || err == ERROR_CALL_NOT_IMPLEMENTED))
+            {
+                // Downgrade to the older implementation
+                impl = remove_disp_ex_flag_posix_semantics;
+                filesystem::detail::atomic_store_relaxed(g_remove_impl_type, impl);
+            }
+            else
+            {
+                break;
+            }
+        }
+        BOOST_FALLTHROUGH;
+
+    case remove_disp_ex_flag_posix_semantics:
+        {
+            file_disposition_info_ex info;
+            info.Flags = FILE_DISPOSITION_FLAG_DELETE | FILE_DISPOSITION_FLAG_POSIX_SEMANTICS;
+            BOOL res = set_file_information_by_handle(handle, file_disposition_info_ex_class, &info, sizeof(info));
+            if (BOOST_LIKELY(!!res))
+            {
+                err = 0u;
+                break;
+            }
+
+            err = ::GetLastError();
+            if (err == ERROR_ACCESS_DENIED)
+            {
+                // Check if the file is read-only and reset the attribute
+                file_basic_info basic_info;
+                res = get_file_information_by_handle_ex(handle, file_basic_info_class, &basic_info, sizeof(basic_info));
+                if (BOOST_UNLIKELY(!res || (basic_info.FileAttributes & FILE_ATTRIBUTE_READONLY) == 0))
+                    break; // return ERROR_ACCESS_DENIED
+
+                basic_info.FileAttributes &= ~FILE_ATTRIBUTE_READONLY;
+
+                res = set_file_information_by_handle(handle, file_basic_info_class, &basic_info, sizeof(basic_info));
+                if (BOOST_UNLIKELY(!res))
+                {
+                    err = ::GetLastError();
+                    break;
+                }
+
+                // Try to set the flag again
+                res = set_file_information_by_handle(handle, file_disposition_info_ex_class, &info, sizeof(info));
+                if (BOOST_LIKELY(!!res))
+                {
+                    err = 0u;
+                    break;
+                }
+
+                err = ::GetLastError();
+
+                // Try to restore the read-only flag
+                basic_info.FileAttributes |= FILE_ATTRIBUTE_READONLY;
+                set_file_information_by_handle(handle, file_basic_info_class, &basic_info, sizeof(basic_info));
+
+                break;
+            }
+            else if (BOOST_UNLIKELY(err == ERROR_INVALID_PARAMETER || err == ERROR_INVALID_FUNCTION || err == ERROR_NOT_SUPPORTED || err == ERROR_CALL_NOT_IMPLEMENTED))
+            {
+                // Downgrade to the older implementation
+                impl = remove_disp;
+                filesystem::detail::atomic_store_relaxed(g_remove_impl_type, impl);
+            }
+            else
+            {
+                break;
+            }
+        }
+        BOOST_FALLTHROUGH;
+
+    default:
+        {
+            file_disposition_info info;
+            info.DeleteFile = true;
+            BOOL res = set_file_information_by_handle(handle, file_disposition_info_class, &info, sizeof(info));
+            if (BOOST_LIKELY(!!res))
+            {
+                err = 0u;
+                break;
+            }
+
+            err = ::GetLastError();
+            if (err == ERROR_ACCESS_DENIED)
+            {
+                // Check if the file is read-only and reset the attribute
+                file_basic_info basic_info;
+                res = get_file_information_by_handle_ex(handle, file_basic_info_class, &basic_info, sizeof(basic_info));
+                if (BOOST_UNLIKELY(!res || (basic_info.FileAttributes & FILE_ATTRIBUTE_READONLY) == 0))
+                    break; // return ERROR_ACCESS_DENIED
+
+                basic_info.FileAttributes &= ~FILE_ATTRIBUTE_READONLY;
+
+                res = set_file_information_by_handle(handle, file_basic_info_class, &basic_info, sizeof(basic_info));
+                if (BOOST_UNLIKELY(!res))
+                {
+                    err = ::GetLastError();
+                    break;
+                }
+
+                // Try to set the flag again
+                res = set_file_information_by_handle(handle, file_disposition_info_class, &info, sizeof(info));
+                if (BOOST_LIKELY(!!res))
+                {
+                    err = 0u;
+                    break;
+                }
+
+                err = ::GetLastError();
+
+                // Try to restore the read-only flag
+                basic_info.FileAttributes |= FILE_ATTRIBUTE_READONLY;
+                set_file_information_by_handle(handle, file_basic_info_class, &basic_info, sizeof(basic_info));
+            }
+
+            break;
+        }
+    }
+
+    return err;
+}
+
+//! remove() implementation for Windows Vista and newer
+inline bool remove_nt6_impl(path const& p, remove_impl_type impl, error_code* ec)
+{
+    unique_handle h(create_file_handle(
+        p,
+        DELETE | FILE_READ_ATTRIBUTES | FILE_READ_EA | FILE_WRITE_ATTRIBUTES | FILE_WRITE_EA,
+        FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT));
+    DWORD err = 0u;
+    if (BOOST_UNLIKELY(!h))
+    {
+        err = ::GetLastError();
+
+    return_error:
+        if (!not_found_error(err))
+            emit_error(err, p, ec, "boost::filesystem::remove");
+
+        return false;
+    }
+
+    err = fs::detail::remove_nt6_by_handle(h.get(), impl);
+    if (BOOST_UNLIKELY(err != 0u))
+        goto return_error;
+
+    return true;
+}
+
+//! remove() implementation
+inline bool remove_impl(path const& p, error_code* ec)
+{
+    remove_impl_type impl = fs::detail::atomic_load_relaxed(g_remove_impl_type);
+    if (BOOST_LIKELY(impl != remove_nt5))
+    {
+        return fs::detail::remove_nt6_impl(p, impl, ec);
+    }
+    else
+    {
+        const DWORD attrs = ::GetFileAttributesW(p.c_str());
+        if (BOOST_UNLIKELY(attrs == INVALID_FILE_ATTRIBUTES))
+        {
+            DWORD err = ::GetLastError();
+            if (!not_found_error(err))
+                emit_error(err, p, ec, "boost::filesystem::remove");
+
+            return false;
+        }
+
+        return fs::detail::remove_nt5_impl(p, attrs, ec);
+    }
+}
+
+//! remove_all() by handle implementation for Windows Vista and newer
+uintmax_t remove_all_nt6_by_handle(HANDLE h, path const& p, error_code* ec)
+{
+    error_code local_ec;
+    fs::file_status st(fs::detail::status_by_handle(h, p, &local_ec));
+    if (BOOST_UNLIKELY(st.type() == fs::status_error))
+    {
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::remove_all", p, local_ec));
+
+        *ec = local_ec;
+        return static_cast< uintmax_t >(-1);
+    }
+
+    uintmax_t count = 0u;
+    if (st.type() == fs::directory_file)
+    {
+        local_ec.clear();
+
+        fs::directory_iterator itr;
+        directory_iterator_params params;
+        params.dir_handle = h;
+        params.close_handle = false; // the caller will close the handle
+        fs::detail::directory_iterator_construct(itr, p, directory_options::_detail_no_follow, &params, &local_ec);
+        if (BOOST_UNLIKELY(!!local_ec))
+        {
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::remove_all", p, local_ec));
+
+            *ec = local_ec;
+            return static_cast< uintmax_t >(-1);
+        }
+
+        NtCreateFile_t* nt_create_file = filesystem::detail::atomic_load_relaxed(nt_create_file_api);
+        const fs::directory_iterator end_dit;
+        while (itr != end_dit)
+        {
+            fs::path nested_path(itr->path());
+            unique_handle hh;
+            if (BOOST_LIKELY(nt_create_file != nullptr))
+            {
+                // Note: WinAPI methods like CreateFileW implicitly request SYNCHRONIZE access but NtCreateFile doesn't.
+                // Without SYNCHRONIZE access querying file attributes via GetFileInformationByHandleEx fails with ERROR_ACCESS_DENIED.
+                boost::winapi::NTSTATUS_ status = nt_create_file_handle_at
+                (
+                    hh,
+                    h,
+                    path_algorithms::filename_v4(nested_path),
+                    0u, // FileAttributes
+                    FILE_LIST_DIRECTORY | DELETE | FILE_READ_ATTRIBUTES | FILE_READ_EA | FILE_WRITE_ATTRIBUTES | FILE_WRITE_EA | SYNCHRONIZE,
+                    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                    FILE_OPEN,
+                    FILE_SYNCHRONOUS_IO_NONALERT | FILE_OPEN_FOR_BACKUP_INTENT | FILE_OPEN_REPARSE_POINT
+                );
+
+                if (!NT_SUCCESS(status))
+                {
+                    if (not_found_ntstatus(status))
+                        goto next_entry;
+
+                    DWORD err = translate_ntstatus(status);
+                    emit_error(err, nested_path, ec, "boost::filesystem::remove_all");
+                    return static_cast< uintmax_t >(-1);
+                }
+            }
+            else
+            {
+                hh = create_file_handle(
+                    nested_path,
+                    FILE_LIST_DIRECTORY | DELETE | FILE_READ_ATTRIBUTES | FILE_READ_EA | FILE_WRITE_ATTRIBUTES | FILE_WRITE_EA | SYNCHRONIZE,
+                    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                    nullptr,
+                    OPEN_EXISTING,
+                    FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT);
+
+                if (BOOST_UNLIKELY(!hh))
+                {
+                    DWORD err = ::GetLastError();
+                    if (not_found_error(err))
+                        goto next_entry;
+
+                    emit_error(err, nested_path, ec, "boost::filesystem::remove_all");
+                    return static_cast< uintmax_t >(-1);
+                }
+            }
+
+            count += fs::detail::remove_all_nt6_by_handle(hh.get(), nested_path, ec);
+            if (ec && *ec)
+                return static_cast< uintmax_t >(-1);
+
+        next_entry:
+            fs::detail::directory_iterator_increment(itr, ec);
+            if (ec && *ec)
+                return static_cast< uintmax_t >(-1);
+        }
+    }
+
+    DWORD err = fs::detail::remove_nt6_by_handle(h, fs::detail::atomic_load_relaxed(g_remove_impl_type));
+    if (BOOST_UNLIKELY(err != 0u))
+    {
+        emit_error(err, p, ec, "boost::filesystem::remove_all");
+        return static_cast< uintmax_t >(-1);
+    }
+
+    ++count;
+    return count;
+}
+
+//! remove_all() implementation for Windows XP and older
+uintmax_t remove_all_nt5_impl(path const& p, error_code* ec)
+{
+    error_code dit_create_ec;
+    for (unsigned int attempt = 0u; attempt < remove_all_directory_replaced_retry_count; ++attempt)
+    {
+        const DWORD attrs = ::GetFileAttributesW(p.c_str());
+        if (BOOST_UNLIKELY(attrs == INVALID_FILE_ATTRIBUTES))
+        {
+            DWORD err = ::GetLastError();
+            if (not_found_error(err))
+                return 0u;
+
+            emit_error(err, p, ec, "boost::filesystem::remove_all");
+            return static_cast< uintmax_t >(-1);
+        }
+
+        // Recurse into directories, but not into junctions or directory symlinks
+        const bool recurse = (attrs & FILE_ATTRIBUTE_DIRECTORY) != 0 && (attrs & FILE_ATTRIBUTE_REPARSE_POINT) == 0;
+        uintmax_t count = 0u;
+        if (recurse)
+        {
+            fs::directory_iterator itr;
+            fs::detail::directory_iterator_construct(itr, p, directory_options::_detail_no_follow, nullptr, &dit_create_ec);
+            if (BOOST_UNLIKELY(!!dit_create_ec))
+            {
+                if (dit_create_ec == make_error_condition(system::errc::not_a_directory) ||
+                    dit_create_ec == make_error_condition(system::errc::too_many_symbolic_link_levels))
+                {
+                    continue;
+                }
+
+                if (!ec)
+                    BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::remove_all", p, dit_create_ec));
+
+                *ec = dit_create_ec;
+                return static_cast< uintmax_t >(-1);
+            }
+
+            const fs::directory_iterator end_dit;
+            while (itr != end_dit)
+            {
+                count += fs::detail::remove_all_nt5_impl(itr->path(), ec);
+                if (ec && *ec)
+                    return static_cast< uintmax_t >(-1);
+
+                fs::detail::directory_iterator_increment(itr, ec);
+                if (ec && *ec)
+                    return static_cast< uintmax_t >(-1);
+            }
+        }
+
+        bool removed = fs::detail::remove_nt5_impl(p, attrs, ec);
+        if (ec && *ec)
+            return static_cast< uintmax_t >(-1);
+
+        count += removed;
+        return count;
+    }
+
+    if (!ec)
+        BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::remove_all: path cannot be opened as a directory", p, dit_create_ec));
+
+    *ec = dit_create_ec;
+    return static_cast< uintmax_t >(-1);
+}
+
+//! remove_all() implementation
+inline uintmax_t remove_all_impl(path const& p, error_code* ec)
+{
+    remove_impl_type impl = fs::detail::atomic_load_relaxed(g_remove_impl_type);
+    if (BOOST_LIKELY(impl != remove_nt5))
+    {
+        unique_handle h(create_file_handle(
+            p,
+            FILE_LIST_DIRECTORY | DELETE | FILE_READ_ATTRIBUTES | FILE_READ_EA | FILE_WRITE_ATTRIBUTES | FILE_WRITE_EA | SYNCHRONIZE,
+            FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+            nullptr,
+            OPEN_EXISTING,
+            FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT));
+
+        if (BOOST_UNLIKELY(!h))
+        {
+            DWORD err = ::GetLastError();
+            if (not_found_error(err))
+                return 0u;
+
+            emit_error(err, p, ec, "boost::filesystem::remove_all");
+            return static_cast< uintmax_t >(-1);
+        }
+
+        return fs::detail::remove_all_nt6_by_handle(h.get(), p, ec);
+    }
+
+    return fs::detail::remove_all_nt5_impl(p, ec);
+}
+
+inline BOOL resize_file_impl(const wchar_t* p, uintmax_t size)
+{
+    unique_handle h(CreateFileW(p, GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr));
+    LARGE_INTEGER sz;
+    sz.QuadPart = size;
+    return !!h && ::SetFilePointerEx(h.get(), sz, 0, FILE_BEGIN) && ::SetEndOfFile(h.get());
+}
+
+//! Converts NT path to a Win32 path
+inline path convert_nt_path_to_win32_path(const wchar_t* nt_path, std::size_t size)
+{
+    // https://googleprojectzero.blogspot.com/2016/02/the-definitive-guide-on-win32-to-nt.html
+    // https://stackoverflow.com/questions/23041983/path-prefixes-and
+    //
+    // NT paths can be used to identify practically any named objects, devices, files, local and remote shares, etc.
+    // The path starts with a leading backslash and consists of one or more path elements separated with backslashes.
+    // The set of characters allowed in NT path elements is significantly larger than that of Win32 paths - basically,
+    // any character except the backslash is allowed. Path elements are case-insensitive.
+    //
+    // NT paths that start with the "\??\" prefix are used to indicate the current user's session namespace. The prefix
+    // indicates to the NT object manager to lookup the object relative to "\Sessions\0\DosDevices\[Logon Authentication ID]".
+    //
+    // There is also a special "\Global??\" prefix that refers to the system logon. User's session directory shadows
+    // the system logon directory, so that when the referenced object is not found in the user's namespace,
+    // system logon is looked up instead.
+    //
+    // There is a symlink "Global" in the user's session namespace that refers to the global namespace, so "\??\Global"
+    // effectively resolves to "\Global??". This allows Win32 applications to directly refer to the system objects,
+    // even if shadowed by the current user's logon object.
+    //
+    // NT paths can be used to reference not only local filesystems, but also devices and remote shares identifiable via
+    // UNC paths. For this, there is a special "UNC" device (which is a symlink to "\Device\Mup") in the system logon
+    // namespace, so "\??\UNC\host\share" (or "\??\Global\UNC\host\share", or "\Global??\UNC\host\share") is equivalent
+    // to "\\host\share".
+    //
+    // NT paths are not universally accepted by Win32 applications and APIs. For example, Far supports paths starting
+    // with "\??\" and "\??\Global\" but not with "\Global??\". As of Win10 21H1, File Explorer, cmd.exe and PowerShell
+    // don't support any of these. Given this, and that NT paths have a different set of allowed characters from Win32 paths,
+    // we should normally avoid exposing NT paths to users that expect Win32 paths.
+    //
+    // In Boost.Filesystem we only deal with NT paths that come from reparse points, such as symlinks and mount points,
+    // including directory junctions. It was observed that reparse points created by junction.exe and mklink use the "\??\"
+    // prefix for directory junctions and absolute symlink and unqualified relative path for relative symlinks.
+    // Absolute paths are using drive letters for mounted drives (e.g. "\??\C:\directory"), although it is possible
+    // to create a junction to an directory using a different way of identifying the filesystem (e.g.
+    // "\??\Volume{00000000-0000-0000-0000-000000000000}\directory").
+    // mklink does not support creating junctions pointing to a UNC path. junction.exe does create a junction that
+    // uses a seemingly invalid syntax like "\??\\\host\share", i.e. it basically does not expect an UNC path. It is not known
+    // if reparse points that refer to a UNC path are considered valid.
+    // There are reparse points created as mount points for local and remote filsystems (for example, a cloud storage mounted
+    // in the local filesystem). Such mount points have the form of "\??\Volume{00000000-0000-0000-0000-000000000000}\",
+    // "\??\Harddisk0Partition1\" or "\??\HarddiskVolume1\".
+    // Reparse points that refer directly to a global namespace (through "\??\Global\" or "\Global??\" prefixes) or
+    // devices (e.g. "\Device\HarddiskVolume1") have not been observed so far.
+
+    path win32_path;
+    std::size_t pos = 0u;
+    bool global_namespace = false;
+
+    // Check for the "\??\" prefix
+    if (size >= 4u &&
+        nt_path[0] == path::preferred_separator &&
+        nt_path[1] == questionmark &&
+        nt_path[2] == questionmark &&
+        nt_path[3] == path::preferred_separator)
+    {
+        pos = 4u;
+
+        // Check "Global"
+        if ((size - pos) >= 6u &&
+            (nt_path[pos] == L'G' || nt_path[pos] == L'g') &&
+            (nt_path[pos + 1] == L'l' || nt_path[pos + 1] == L'L') &&
+            (nt_path[pos + 2] == L'o' || nt_path[pos + 2] == L'O') &&
+            (nt_path[pos + 3] == L'b' || nt_path[pos + 3] == L'B') &&
+            (nt_path[pos + 4] == L'a' || nt_path[pos + 4] == L'A') &&
+            (nt_path[pos + 5] == L'l' || nt_path[pos + 5] == L'L'))
+        {
+            if ((size - pos) == 6u)
+            {
+                pos += 6u;
+                global_namespace = true;
+            }
+            else if (detail::is_directory_separator(nt_path[pos + 6u]))
+            {
+                pos += 7u;
+                global_namespace = true;
+            }
+        }
+    }
+    // Check for the "\Global??\" prefix
+    else if (size >= 10u &&
+        nt_path[0] == path::preferred_separator &&
+        (nt_path[1] == L'G' || nt_path[1] == L'g') &&
+        (nt_path[2] == L'l' || nt_path[2] == L'L') &&
+        (nt_path[3] == L'o' || nt_path[3] == L'O') &&
+        (nt_path[4] == L'b' || nt_path[4] == L'B') &&
+        (nt_path[5] == L'a' || nt_path[5] == L'A') &&
+        (nt_path[6] == L'l' || nt_path[6] == L'L') &&
+        nt_path[7] == questionmark &&
+        nt_path[8] == questionmark &&
+        nt_path[9] == path::preferred_separator)
+    {
+        pos = 10u;
+        global_namespace = true;
+    }
+
+    if (pos > 0u)
+    {
+        if ((size - pos) >= 2u &&
+        (
+            // Check if the following is a drive letter
+            (
+                detail::is_letter(nt_path[pos]) && nt_path[pos + 1u] == colon &&
+                ((size - pos) == 2u || detail::is_directory_separator(nt_path[pos + 2u]))
+            ) ||
+            // Check for an "incorrect" syntax for UNC path junction points
+            (
+                detail::is_directory_separator(nt_path[pos]) && detail::is_directory_separator(nt_path[pos + 1u]) &&
+                ((size - pos) == 2u || !detail::is_directory_separator(nt_path[pos + 2u]))
+            )
+        ))
+        {
+            // Strip the NT path prefix
+            goto done;
+        }
+
+        static const wchar_t win32_path_prefix[4u] = { path::preferred_separator, path::preferred_separator, questionmark, path::preferred_separator };
+
+        // Check for a UNC path
+        if ((size - pos) >= 4u &&
+            (nt_path[pos] == L'U' || nt_path[pos] == L'u') &&
+            (nt_path[pos + 1] == L'N' || nt_path[pos + 1] == L'n') &&
+            (nt_path[pos + 2] == L'C' || nt_path[pos + 2] == L'c') &&
+            nt_path[pos + 3] == path::preferred_separator)
+        {
+            win32_path.assign(win32_path_prefix, win32_path_prefix + 2);
+            pos += 4u;
+            goto done;
+        }
+
+        // This is some other NT path, possibly a volume mount point. Replace the NT prefix with a Win32 filesystem prefix "\\?\".
+        win32_path.assign(win32_path_prefix, win32_path_prefix + 4);
+        if (global_namespace)
+        {
+            static const wchar_t win32_path_global_prefix[7u] = { L'G', L'l', L'o', L'b', L'a', L'l', path::preferred_separator };
+            win32_path.concat(win32_path_global_prefix, win32_path_global_prefix + 7);
+        }
+    }
+
+done:
+    win32_path.concat(nt_path + pos, nt_path + size);
+    return win32_path;
+}
+
+#endif // defined(BOOST_POSIX_API)
+
+} // unnamed namespace
+
+} // namespace detail
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//                operations functions declared in operations.hpp                       //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+namespace detail {
+
+BOOST_FILESYSTEM_DECL bool possible_large_file_size_support()
+{
+#ifdef BOOST_POSIX_API
+    typedef struct stat struct_stat;
+    return sizeof(struct_stat().st_size) > 4;
+#else
+    return true;
+#endif
+}
+
+BOOST_FILESYSTEM_DECL
+path absolute_v3(path const& p, path const& base, system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+    if (p.is_absolute())
+        return p;
+
+    //  recursively calling absolute is sub-optimal, but is sure and simple
+    path abs_base = base;
+    if (!base.is_absolute())
+    {
+        path cur_path = detail::current_path(ec);
+        if (ec && *ec)
+        {
+        return_empty_path:
+            return path();
+        }
+
+        if (BOOST_UNLIKELY(!cur_path.is_absolute()))
+        {
+            system::error_code local_ec = system::errc::make_error_code(system::errc::invalid_argument);
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::absolute", p, base, local_ec));
+
+            *ec = local_ec;
+            goto return_empty_path;
+        }
+
+        abs_base = detail::absolute_v3(base, cur_path, ec);
+        if (ec && *ec)
+            goto return_empty_path;
+    }
+
+    if (p.empty())
+        return abs_base;
+
+    path res;
+    if (p.has_root_name())
+        res = p.root_name();
+    else
+        res = abs_base.root_name();
+
+    if (p.has_root_directory())
+    {
+        res.concat(p.root_directory());
+    }
+    else
+    {
+        res.concat(abs_base.root_directory());
+        path_algorithms::append_v4(res, abs_base.relative_path());
+    }
+
+    path p_relative_path(p.relative_path());
+    if (!p_relative_path.empty())
+        path_algorithms::append_v4(res, p_relative_path);
+
+    return res;
+}
+
+BOOST_FILESYSTEM_DECL
+path absolute_v4(path const& p, path const& base, system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+    if (p.is_absolute())
+        return p;
+
+    path abs_base = base;
+    if (!base.is_absolute())
+    {
+        path cur_path = detail::current_path(ec);
+        if (ec && *ec)
+        {
+        return_empty_path:
+            return path();
+        }
+
+        if (BOOST_UNLIKELY(!cur_path.is_absolute()))
+        {
+            system::error_code local_ec = system::errc::make_error_code(system::errc::invalid_argument);
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::absolute", p, base, local_ec));
+
+            *ec = local_ec;
+            goto return_empty_path;
+        }
+
+        abs_base = detail::absolute_v4(base, cur_path, ec);
+        if (ec && *ec)
+            goto return_empty_path;
+    }
+
+    path res;
+    if (p.has_root_name())
+        res = p.root_name();
+    else
+        res = abs_base.root_name();
+
+    if (p.has_root_directory())
+    {
+        res.concat(p.root_directory());
+    }
+    else
+    {
+        res.concat(abs_base.root_directory());
+        path_algorithms::append_v4(res, abs_base.relative_path());
+    }
+
+    path_algorithms::append_v4(res, p.relative_path());
+
+    return res;
+}
+
+BOOST_FILESYSTEM_DECL
+path canonical_v3(path const& p, path const& base, system::error_code* ec)
+{
+    path source(detail::absolute_v3(p, base, ec));
+    if (ec && *ec)
+    {
+    return_empty_path:
+        return path();
+    }
+
+    system::error_code local_ec;
+    file_status st(detail::status_impl(source, &local_ec));
+
+    if (st.type() == fs::file_not_found)
+    {
+        local_ec = system::errc::make_error_code(system::errc::no_such_file_or_directory);
+        goto fail_local_ec;
+    }
+    else if (local_ec)
+    {
+    fail_local_ec:
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::canonical", source, local_ec));
+
+        *ec = local_ec;
+        goto return_empty_path;
+    }
+
+    path root(source.root_path());
+    path const& dot_p = dot_path();
+    path const& dot_dot_p = dot_dot_path();
+    unsigned int symlinks_allowed = symloop_max;
+    path result;
+    while (true)
+    {
+        for (path::iterator itr(source.begin()), end(source.end()); itr != end; path_algorithms::increment_v4(itr))
+        {
+            if (path_algorithms::compare_v4(*itr, dot_p) == 0)
+                continue;
+            if (path_algorithms::compare_v4(*itr, dot_dot_p) == 0)
+            {
+                if (path_algorithms::compare_v4(result, root) != 0)
+                    result.remove_filename_and_trailing_separators();
+                continue;
+            }
+
+            if (itr->size() == 1u && detail::is_directory_separator(itr->native()[0]))
+            {
+                // Convert generic separator returned by the iterator for the root directory to
+                // the preferred separator. This is important on Windows, as in some cases,
+                // like paths for network shares and cloud storage mount points GetFileAttributesW
+                // will return "file not found" if the path contains forward slashes.
+                result += path::preferred_separator;
+                // We don't need to check for a symlink after adding a separator.
+                continue;
+            }
+
+            path_algorithms::append_v4(result, *itr);
+
+            // If we don't have an absolute path yet then don't check symlink status.
+            // This avoids checking "C:" which is "the current directory on drive C"
+            // and hence not what we want to check/resolve here.
+            if (!result.is_absolute())
+                continue;
+
+            st = detail::symlink_status_impl(result, ec);
+            if (ec && *ec)
+                goto return_empty_path;
+
+            if (is_symlink(st))
+            {
+                if (symlinks_allowed == 0)
+                {
+                    local_ec = system::errc::make_error_code(system::errc::too_many_symbolic_link_levels);
+                    goto fail_local_ec;
+                }
+
+                --symlinks_allowed;
+
+                path link(detail::read_symlink(result, ec));
+                if (ec && *ec)
+                    goto return_empty_path;
+                result.remove_filename_and_trailing_separators();
+
+                if (link.is_absolute())
+                {
+                    for (path_algorithms::increment_v4(itr); itr != end; path_algorithms::increment_v4(itr))
+                    {
+                        if (path_algorithms::compare_v4(*itr, dot_p) != 0)
+                            path_algorithms::append_v4(link, *itr);
+                    }
+                    source = link;
+                    root = source.root_path();
+                }
+                else // link is relative
+                {
+                    link.remove_trailing_separator();
+                    if (path_algorithms::compare_v4(link, dot_p) == 0)
+                        continue;
+
+                    path new_source(result);
+                    path_algorithms::append_v4(new_source, link);
+                    for (path_algorithms::increment_v4(itr); itr != end; path_algorithms::increment_v4(itr))
+                    {
+                        if (path_algorithms::compare_v4(*itr, dot_p) != 0)
+                            path_algorithms::append_v4(new_source, *itr);
+                    }
+                    source = new_source;
+                }
+
+                // symlink causes scan to be restarted
+                goto restart_scan;
+            }
+        }
+
+        break;
+
+    restart_scan:
+        result.clear();
+    }
+
+    BOOST_ASSERT_MSG(result.is_absolute(), "canonical() implementation error; please report");
+    return result;
+}
+
+BOOST_FILESYSTEM_DECL
+path canonical_v4(path const& p, path const& base, system::error_code* ec)
+{
+    path source(detail::absolute_v4(p, base, ec));
+    if (ec && *ec)
+    {
+    return_empty_path:
+        return path();
+    }
+
+    system::error_code local_ec;
+    file_status st(detail::status_impl(source, &local_ec));
+
+    if (st.type() == fs::file_not_found)
+    {
+        local_ec = system::errc::make_error_code(system::errc::no_such_file_or_directory);
+        goto fail_local_ec;
+    }
+    else if (local_ec)
+    {
+    fail_local_ec:
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::canonical", source, local_ec));
+
+        *ec = local_ec;
+        goto return_empty_path;
+    }
+
+    path root(source.root_path());
+    path const& dot_p = dot_path();
+    path const& dot_dot_p = dot_dot_path();
+    unsigned int symlinks_allowed = symloop_max;
+    path result;
+    while (true)
+    {
+        for (path::iterator itr(source.begin()), end(source.end()); itr != end; path_algorithms::increment_v4(itr))
+        {
+            if (path_algorithms::compare_v4(*itr, dot_p) == 0)
+                continue;
+            if (path_algorithms::compare_v4(*itr, dot_dot_p) == 0)
+            {
+                if (path_algorithms::compare_v4(result, root) != 0)
+                    result.remove_filename_and_trailing_separators();
+                continue;
+            }
+
+            if (itr->size() == 1u && detail::is_directory_separator(itr->native()[0]))
+            {
+                // Convert generic separator returned by the iterator for the root directory to
+                // the preferred separator. This is important on Windows, as in some cases,
+                // like paths for network shares and cloud storage mount points GetFileAttributesW
+                // will return "file not found" if the path contains forward slashes.
+                result += path::preferred_separator;
+                // We don't need to check for a symlink after adding a separator.
+                continue;
+            }
+
+            path_algorithms::append_v4(result, *itr);
+
+            // If we don't have an absolute path yet then don't check symlink status.
+            // This avoids checking "C:" which is "the current directory on drive C"
+            // and hence not what we want to check/resolve here.
+            if (!result.is_absolute())
+                continue;
+
+            st = detail::symlink_status_impl(result, ec);
+            if (ec && *ec)
+                goto return_empty_path;
+
+            if (is_symlink(st))
+            {
+                if (symlinks_allowed == 0)
+                {
+                    local_ec = system::errc::make_error_code(system::errc::too_many_symbolic_link_levels);
+                    goto fail_local_ec;
+                }
+
+                --symlinks_allowed;
+
+                path link(detail::read_symlink(result, ec));
+                if (ec && *ec)
+                    goto return_empty_path;
+                result.remove_filename_and_trailing_separators();
+
+                if (link.is_absolute())
+                {
+                    for (path_algorithms::increment_v4(itr); itr != end; path_algorithms::increment_v4(itr))
+                    {
+                        if (path_algorithms::compare_v4(*itr, dot_p) != 0)
+                            path_algorithms::append_v4(link, *itr);
+                    }
+                    source = link;
+                    root = source.root_path();
+                }
+                else // link is relative
+                {
+                    link.remove_trailing_separator();
+                    if (path_algorithms::compare_v4(link, dot_p) == 0)
+                        continue;
+
+                    path new_source(result);
+                    path_algorithms::append_v4(new_source, link);
+                    for (path_algorithms::increment_v4(itr); itr != end; path_algorithms::increment_v4(itr))
+                    {
+                        if (path_algorithms::compare_v4(*itr, dot_p) != 0)
+                            path_algorithms::append_v4(new_source, *itr);
+                    }
+                    source = new_source;
+                }
+
+                // symlink causes scan to be restarted
+                goto restart_scan;
+            }
+        }
+
+        break;
+
+    restart_scan:
+        result.clear();
+    }
+
+    BOOST_ASSERT_MSG(result.is_absolute(), "canonical() implementation error; please report");
+    return result;
+}
+
+BOOST_FILESYSTEM_DECL
+void copy(path const& from, path const& to, copy_options options, system::error_code* ec)
+{
+    BOOST_ASSERT((((options & copy_options::overwrite_existing) != copy_options::none) +
+        ((options & copy_options::skip_existing) != copy_options::none) +
+        ((options & copy_options::update_existing) != copy_options::none)) <= 1);
+
+    BOOST_ASSERT((((options & copy_options::copy_symlinks) != copy_options::none) +
+        ((options & copy_options::skip_symlinks) != copy_options::none)) <= 1);
+
+    BOOST_ASSERT((((options & copy_options::directories_only) != copy_options::none) +
+        ((options & copy_options::create_symlinks) != copy_options::none) +
+        ((options & copy_options::create_hard_links) != copy_options::none)) <= 1);
+
+    if (ec)
+        ec->clear();
+
+    file_status from_stat;
+    if ((options & (copy_options::copy_symlinks | copy_options::skip_symlinks | copy_options::create_symlinks)) != copy_options::none)
+    {
+        from_stat = detail::symlink_status_impl(from, ec);
+    }
+    else
+    {
+        from_stat = detail::status_impl(from, ec);
+    }
+
+    if (ec && *ec)
+        return;
+
+    if (!exists(from_stat))
+    {
+        emit_error(BOOST_ERROR_FILE_NOT_FOUND, from, to, ec, "boost::filesystem::copy");
+        return;
+    }
+
+    if (is_symlink(from_stat))
+    {
+        if ((options & copy_options::skip_symlinks) != copy_options::none)
+            return;
+
+        if ((options & copy_options::copy_symlinks) == copy_options::none)
+            goto fail;
+
+        detail::copy_symlink(from, to, ec);
+    }
+    else if (is_regular_file(from_stat))
+    {
+        if ((options & copy_options::directories_only) != copy_options::none)
+            return;
+
+        if ((options & copy_options::create_symlinks) != copy_options::none)
+        {
+            const path* pfrom = &from;
+            path relative_from;
+            if (!from.is_absolute())
+            {
+                // Try to generate a relative path from the target location to the original file
+                path cur_dir = detail::current_path(ec);
+                if (ec && *ec)
+                    return;
+                path abs_from = detail::absolute_v4(from.parent_path(), cur_dir, ec);
+                if (ec && *ec)
+                    return;
+                path abs_to = to.parent_path();
+                if (!abs_to.is_absolute())
+                {
+                    abs_to = detail::absolute_v4(abs_to, cur_dir, ec);
+                    if (ec && *ec)
+                        return;
+                }
+                relative_from = detail::relative(abs_from, abs_to, ec);
+                if (ec && *ec)
+                    return;
+                if (path_algorithms::compare_v4(relative_from, dot_path()) != 0)
+                    path_algorithms::append_v4(relative_from, path_algorithms::filename_v4(from));
+                else
+                    relative_from = path_algorithms::filename_v4(from);
+                pfrom = &relative_from;
+            }
+            detail::create_symlink(*pfrom, to, ec);
+            return;
+        }
+
+        if ((options & copy_options::create_hard_links) != copy_options::none)
+        {
+            detail::create_hard_link(from, to, ec);
+            return;
+        }
+
+        error_code local_ec;
+        file_status to_stat;
+        if ((options & (copy_options::skip_symlinks | copy_options::create_symlinks)) != copy_options::none)
+        {
+            to_stat = detail::symlink_status_impl(to, &local_ec);
+        }
+        else
+        {
+            to_stat = detail::status_impl(to, &local_ec);
+        }
+
+        // Note: local_ec may be set by (symlink_)status() even in some non-fatal situations, e.g. when the file does not exist.
+        //       OTOH, when it returns status_error, then a real error have happened and it must have set local_ec.
+        if (to_stat.type() == fs::status_error)
+        {
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::copy", from, to, local_ec));
+            *ec = local_ec;
+            return;
+        }
+
+        if (is_directory(to_stat))
+        {
+            path target(to);
+            path_algorithms::append_v4(target, path_algorithms::filename_v4(from));
+            detail::copy_file(from, target, options, ec);
+        }
+        else
+            detail::copy_file(from, to, options, ec);
+    }
+    else if (is_directory(from_stat))
+    {
+        error_code local_ec;
+        if ((options & copy_options::create_symlinks) != copy_options::none)
+        {
+            local_ec = make_error_code(system::errc::is_a_directory);
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::copy", from, to, local_ec));
+            *ec = local_ec;
+            return;
+        }
+
+        file_status to_stat;
+        if ((options & (copy_options::skip_symlinks | copy_options::create_symlinks)) != copy_options::none)
+        {
+            to_stat = detail::symlink_status_impl(to, &local_ec);
+        }
+        else
+        {
+            to_stat = detail::status_impl(to, &local_ec);
+        }
+
+        // Note: ec may be set by (symlink_)status() even in some non-fatal situations, e.g. when the file does not exist.
+        //       OTOH, when it returns status_error, then a real error have happened and it must have set local_ec.
+        if (to_stat.type() == fs::status_error)
+        {
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::copy", from, to, local_ec));
+            *ec = local_ec;
+            return;
+        }
+
+        if (!exists(to_stat))
+        {
+            detail::create_directory(to, &from, ec);
+            if (ec && *ec)
+                return;
+        }
+
+        if ((options & copy_options::recursive) != copy_options::none || options == copy_options::none)
+        {
+            fs::directory_iterator itr;
+            detail::directory_iterator_construct(itr, from, directory_options::none, nullptr, ec);
+            if (ec && *ec)
+                return;
+
+            const fs::directory_iterator end_dit;
+            while (itr != end_dit)
+            {
+                path const& p = itr->path();
+                {
+                    path target(to);
+                    path_algorithms::append_v4(target, path_algorithms::filename_v4(p));
+                    // Set _detail_recursing flag so that we don't recurse more than for one level deeper into the directory if options are copy_options::none
+                    detail::copy(p, target, options | copy_options::_detail_recursing, ec);
+                }
+                if (ec && *ec)
+                    return;
+
+                detail::directory_iterator_increment(itr, ec);
+                if (ec && *ec)
+                    return;
+            }
+        }
+    }
+    else
+    {
+    fail:
+        emit_error(BOOST_ERROR_NOT_SUPPORTED, from, to, ec, "boost::filesystem::copy");
+    }
+}
+
+BOOST_FILESYSTEM_DECL
+bool copy_file(path const& from, path const& to, copy_options options, error_code* ec)
+{
+    BOOST_ASSERT((((options & copy_options::overwrite_existing) != copy_options::none) +
+        ((options & copy_options::skip_existing) != copy_options::none) +
+        ((options & copy_options::update_existing) != copy_options::none)) <= 1);
+
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+
+    int err = 0;
+
+    // Note: Declare fd wrappers here so that errno is not clobbered by close() that may be called in fd wrapper destructors
+    boost::scope::unique_fd infile, outfile;
+
+    while (true)
+    {
+        infile.reset(::open(from.c_str(), O_RDONLY | O_CLOEXEC));
+        if (BOOST_UNLIKELY(!infile))
+        {
+            err = errno;
+            if (err == EINTR)
+                continue;
+
+        fail:
+            emit_error(err, from, to, ec, "boost::filesystem::copy_file");
+            return false;
+        }
+
+        break;
+    }
+
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    unsigned int statx_data_mask = STATX_TYPE | STATX_MODE | STATX_INO | STATX_SIZE;
+    if ((options & copy_options::update_existing) != copy_options::none)
+        statx_data_mask |= STATX_MTIME;
+
+    struct ::statx from_stat;
+    if (BOOST_UNLIKELY(invoke_statx(infile.get(), "", AT_EMPTY_PATH | AT_NO_AUTOMOUNT, statx_data_mask, &from_stat) < 0))
+    {
+    fail_errno:
+        err = errno;
+        goto fail;
+    }
+
+    if (BOOST_UNLIKELY((from_stat.stx_mask & statx_data_mask) != statx_data_mask))
+    {
+        err = ENOSYS;
+        goto fail;
+    }
+#else
+    struct ::stat from_stat;
+    if (BOOST_UNLIKELY(::fstat(infile.get(), &from_stat) != 0))
+    {
+    fail_errno:
+        err = errno;
+        goto fail;
+    }
+#endif
+
+    const mode_t from_mode = get_mode(from_stat);
+    if (BOOST_UNLIKELY(!S_ISREG(from_mode)))
+    {
+        err = ENOSYS;
+        goto fail;
+    }
+
+    mode_t to_mode = from_mode & fs::perms_mask;
+#if !defined(BOOST_FILESYSTEM_USE_WASI)
+    // Enable writing for the newly created files. Having write permission set is important e.g. for NFS,
+    // which checks the file permission on the server, even if the client's file descriptor supports writing.
+    to_mode |= S_IWUSR;
+#endif
+    int oflag = O_WRONLY | O_CLOEXEC;
+
+    if ((options & copy_options::update_existing) != copy_options::none)
+    {
+        // Try opening the existing file without truncation to test the modification time later
+        while (true)
+        {
+            outfile.reset(::open(to.c_str(), oflag, to_mode));
+            if (!outfile)
+            {
+                err = errno;
+                if (err == EINTR)
+                    continue;
+
+                if (err == ENOENT)
+                    goto create_outfile;
+
+                goto fail;
+            }
+
+            break;
+        }
+    }
+    else
+    {
+    create_outfile:
+        oflag |= O_CREAT | O_TRUNC;
+        if (((options & copy_options::overwrite_existing) == copy_options::none ||
+             (options & copy_options::skip_existing) != copy_options::none) &&
+            (options & copy_options::update_existing) == copy_options::none)
+        {
+            oflag |= O_EXCL;
+        }
+
+        while (true)
+        {
+            outfile.reset(::open(to.c_str(), oflag, to_mode));
+            if (!outfile)
+            {
+                err = errno;
+                if (err == EINTR)
+                    continue;
+
+                if (err == EEXIST && (options & copy_options::skip_existing) != copy_options::none)
+                    return false;
+
+                goto fail;
+            }
+
+            break;
+        }
+    }
+
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    statx_data_mask = STATX_TYPE | STATX_MODE | STATX_INO;
+    if ((oflag & O_TRUNC) == 0)
+    {
+        // O_TRUNC is not set if copy_options::update_existing is set and an existing file was opened.
+        statx_data_mask |= STATX_MTIME;
+    }
+
+    struct ::statx to_stat;
+    if (BOOST_UNLIKELY(invoke_statx(outfile.get(), "", AT_EMPTY_PATH | AT_NO_AUTOMOUNT, statx_data_mask, &to_stat) < 0))
+        goto fail_errno;
+
+    if (BOOST_UNLIKELY((to_stat.stx_mask & statx_data_mask) != statx_data_mask))
+    {
+        err = ENOSYS;
+        goto fail;
+    }
+#else
+    struct ::stat to_stat;
+    if (BOOST_UNLIKELY(::fstat(outfile.get(), &to_stat) != 0))
+        goto fail_errno;
+#endif
+
+    to_mode = get_mode(to_stat);
+    if (BOOST_UNLIKELY(!S_ISREG(to_mode)))
+    {
+        err = ENOSYS;
+        goto fail;
+    }
+
+    if (BOOST_UNLIKELY(detail::equivalent_stat(from_stat, to_stat)))
+    {
+        err = EEXIST;
+        goto fail;
+    }
+
+    if ((oflag & O_TRUNC) == 0)
+    {
+        // O_TRUNC is not set if copy_options::update_existing is set and an existing file was opened.
+        // We need to check the last write times.
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+        if (from_stat.stx_mtime.tv_sec < to_stat.stx_mtime.tv_sec || (from_stat.stx_mtime.tv_sec == to_stat.stx_mtime.tv_sec && from_stat.stx_mtime.tv_nsec <= to_stat.stx_mtime.tv_nsec))
+            return false;
+#elif defined(BOOST_FILESYSTEM_STAT_ST_MTIMENSEC)
+        // Modify time is available with nanosecond precision.
+        if (from_stat.st_mtime < to_stat.st_mtime || (from_stat.st_mtime == to_stat.st_mtime && from_stat.BOOST_FILESYSTEM_STAT_ST_MTIMENSEC <= to_stat.BOOST_FILESYSTEM_STAT_ST_MTIMENSEC))
+            return false;
+#else
+        if (from_stat.st_mtime <= to_stat.st_mtime)
+            return false;
+#endif
+
+        if (BOOST_UNLIKELY(::ftruncate(outfile.get(), 0) != 0))
+            goto fail_errno;
+    }
+
+    // Note: Use block size of the target file since it is most important for writing performance.
+    err = filesystem::detail::atomic_load_relaxed(filesystem::detail::copy_file_data)(infile.get(), outfile.get(), get_size(from_stat), get_blksize(to_stat));
+    if (BOOST_UNLIKELY(err != 0))
+        goto fail; // err already contains the error code
+
+#if !defined(BOOST_FILESYSTEM_USE_WASI)
+    // If we created a new file with an explicitly added S_IWUSR permission,
+    // we may need to update its mode bits to match the source file.
+    if ((to_mode & fs::perms_mask) != (from_mode & fs::perms_mask))
+    {
+        if (BOOST_UNLIKELY(::fchmod(outfile.get(), (from_mode & fs::perms_mask)) != 0 &&
+            (options & copy_options::ignore_attribute_errors) == copy_options::none))
+        {
+            goto fail_errno;
+        }
+    }
+#endif
+
+    if ((options & (copy_options::synchronize_data | copy_options::synchronize)) != copy_options::none)
+    {
+        if ((options & copy_options::synchronize) != copy_options::none)
+            err = full_sync(outfile.get());
+        else
+            err = data_sync(outfile.get());
+
+        if (BOOST_UNLIKELY(err != 0))
+            goto fail;
+    }
+
+    // We have to explicitly close the output file descriptor in order to handle a possible error returned from it. The error may indicate
+    // a failure of a prior write operation.
+    err = close_fd(outfile.get());
+    outfile.release();
+    if (BOOST_UNLIKELY(err < 0))
+    {
+        err = errno;
+        // EINPROGRESS is an allowed error code in future POSIX revisions, according to https://www.austingroupbugs.net/view.php?id=529#c1200.
+        if (err != EINTR && err != EINPROGRESS)
+            goto fail;
+    }
+
+    return true;
+
+#else // defined(BOOST_POSIX_API)
+
+    DWORD copy_flags = 0u;
+    if ((options & copy_options::overwrite_existing) == copy_options::none ||
+        (options & copy_options::skip_existing) != copy_options::none)
+    {
+        copy_flags |= COPY_FILE_FAIL_IF_EXISTS;
+    }
+
+    if ((options & copy_options::update_existing) != copy_options::none)
+    {
+        // Create unique_handle wrappers here so that CloseHandle calls don't clobber error code returned by GetLastError
+        unique_handle hw_from, hw_to;
+
+        // See the comment in last_write_time regarding access rights used here for GetFileTime.
+        hw_from = create_file_handle(
+            from.c_str(),
+            FILE_READ_ATTRIBUTES | FILE_READ_EA,
+            FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+            nullptr,
+            OPEN_EXISTING,
+            FILE_FLAG_BACKUP_SEMANTICS);
+
+        FILETIME lwt_from;
+        if (!hw_from)
+        {
+        fail_last_error:
+            DWORD err = ::GetLastError();
+            emit_error(err, from, to, ec, "boost::filesystem::copy_file");
+            return false;
+        }
+
+        if (!::GetFileTime(hw_from.get(), nullptr, nullptr, &lwt_from))
+            goto fail_last_error;
+
+        hw_to = create_file_handle(
+            to.c_str(),
+            FILE_READ_ATTRIBUTES | FILE_READ_EA,
+            FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+            nullptr,
+            OPEN_EXISTING,
+            FILE_FLAG_BACKUP_SEMANTICS);
+
+        if (!!hw_to)
+        {
+            FILETIME lwt_to;
+            if (!::GetFileTime(hw_to.get(), nullptr, nullptr, &lwt_to))
+                goto fail_last_error;
+
+            ULONGLONG tfrom = (static_cast< ULONGLONG >(lwt_from.dwHighDateTime) << 32) | static_cast< ULONGLONG >(lwt_from.dwLowDateTime);
+            ULONGLONG tto = (static_cast< ULONGLONG >(lwt_to.dwHighDateTime) << 32) | static_cast< ULONGLONG >(lwt_to.dwLowDateTime);
+            if (tfrom <= tto)
+                return false;
+        }
+
+        copy_flags &= ~static_cast< DWORD >(COPY_FILE_FAIL_IF_EXISTS);
+    }
+
+    struct callback_context
+    {
+        DWORD flush_error;
+    };
+
+    struct local
+    {
+        //! Callback that is called to report progress of \c CopyFileExW
+        static DWORD WINAPI on_copy_file_progress(
+            LARGE_INTEGER total_file_size,
+            LARGE_INTEGER total_bytes_transferred,
+            LARGE_INTEGER stream_size,
+            LARGE_INTEGER stream_bytes_transferred,
+            DWORD stream_number,
+            DWORD callback_reason,
+            HANDLE from_handle,
+            HANDLE to_handle,
+            LPVOID ctx)
+        {
+            // For each stream, CopyFileExW will open a separate pair of file handles, so we need to flush each stream separately.
+            if (stream_bytes_transferred.QuadPart == stream_size.QuadPart)
+            {
+                BOOL res = ::FlushFileBuffers(to_handle);
+                if (BOOST_UNLIKELY(!res))
+                {
+                    callback_context* context = static_cast< callback_context* >(ctx);
+                    if (BOOST_LIKELY(context->flush_error == 0u))
+                        context->flush_error = ::GetLastError();
+                }
+            }
+
+            return PROGRESS_CONTINUE;
+        }
+    };
+
+    callback_context cb_context = {};
+    LPPROGRESS_ROUTINE cb = nullptr;
+    LPVOID cb_ctx = nullptr;
+
+    if ((options & (copy_options::synchronize_data | copy_options::synchronize)) != copy_options::none)
+    {
+        cb = &local::on_copy_file_progress;
+        cb_ctx = &cb_context;
+    }
+
+    BOOL cancelled = FALSE;
+    BOOL res = ::CopyFileExW(from.c_str(), to.c_str(), cb, cb_ctx, &cancelled, copy_flags);
+    DWORD err;
+    if (BOOST_UNLIKELY(!res))
+    {
+        err = ::GetLastError();
+        if ((err == ERROR_FILE_EXISTS || err == ERROR_ALREADY_EXISTS) && (options & copy_options::skip_existing) != copy_options::none)
+            return false;
+
+    copy_failed:
+        emit_error(err, from, to, ec, "boost::filesystem::copy_file");
+        return false;
+    }
+
+    if (BOOST_UNLIKELY(cb_context.flush_error != 0u))
+    {
+        err = cb_context.flush_error;
+        goto copy_failed;
+    }
+
+    return true;
+
+#endif // defined(BOOST_POSIX_API)
+}
+
+BOOST_FILESYSTEM_DECL
+void copy_symlink(path const& existing_symlink, path const& new_symlink, system::error_code* ec)
+{
+    path p(read_symlink(existing_symlink, ec));
+    if (ec && *ec)
+        return;
+    create_symlink(p, new_symlink, ec);
+}
+
+BOOST_FILESYSTEM_DECL
+bool create_directories(path const& p, system::error_code* ec)
+{
+    if (p.empty())
+    {
+        if (!ec)
+        {
+            BOOST_FILESYSTEM_THROW(filesystem_error(
+                "boost::filesystem::create_directories", p,
+                system::errc::make_error_code(system::errc::invalid_argument)));
+        }
+        ec->assign(system::errc::invalid_argument, system::generic_category());
+        return false;
+    }
+
+    if (ec)
+        ec->clear();
+
+    path::const_iterator e(p.end()), it(e);
+    path parent(p);
+    path const& dot_p = dot_path();
+    path const& dot_dot_p = dot_dot_path();
+    error_code local_ec;
+
+    // Find the initial part of the path that exists
+    for (path fname = path_algorithms::filename_v4(parent); parent.has_relative_path(); fname = path_algorithms::filename_v4(parent))
+    {
+        if (!fname.empty() && path_algorithms::compare_v4(fname, dot_p) != 0 && path_algorithms::compare_v4(fname, dot_dot_p) != 0)
+        {
+            file_status existing_status = detail::status_impl(parent, &local_ec);
+
+            if (existing_status.type() == directory_file)
+            {
+                break;
+            }
+            else if (BOOST_UNLIKELY(existing_status.type() == status_error))
+            {
+                if (!ec)
+                    BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::create_directories", p, parent, local_ec));
+                *ec = local_ec;
+                return false;
+            }
+        }
+
+        path_algorithms::decrement_v4(it);
+        parent.remove_filename_and_trailing_separators();
+    }
+
+    // Create missing directories
+    bool created = false;
+    for (; it != e; path_algorithms::increment_v4(it))
+    {
+        path const& fname = *it;
+        path_algorithms::append_v4(parent, fname);
+        if (!fname.empty() && path_algorithms::compare_v4(fname, dot_p) != 0 && path_algorithms::compare_v4(fname, dot_dot_p) != 0)
+        {
+            created = detail::create_directory(parent, nullptr, &local_ec);
+            if (BOOST_UNLIKELY(!!local_ec))
+            {
+                if (!ec)
+                    BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::create_directories", p, parent, local_ec));
+                *ec = local_ec;
+                return false;
+            }
+        }
+    }
+
+    return created;
+}
+
+BOOST_FILESYSTEM_DECL
+bool create_directory(path const& p, const path* existing, error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+
+    mode_t mode = S_IRWXU | S_IRWXG | S_IRWXO;
+    if (existing)
+    {
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+        struct ::statx existing_stat;
+        if (BOOST_UNLIKELY(invoke_statx(AT_FDCWD, existing->c_str(), AT_NO_AUTOMOUNT, STATX_TYPE | STATX_MODE, &existing_stat) < 0))
+        {
+            emit_error(errno, p, *existing, ec, "boost::filesystem::create_directory");
+            return false;
+        }
+
+        if (BOOST_UNLIKELY((existing_stat.stx_mask & (STATX_TYPE | STATX_MODE)) != (STATX_TYPE | STATX_MODE)))
+        {
+            emit_error(BOOST_ERROR_NOT_SUPPORTED, p, *existing, ec, "boost::filesystem::create_directory");
+            return false;
+        }
+#else
+        struct ::stat existing_stat;
+        if (::stat(existing->c_str(), &existing_stat) < 0)
+        {
+            emit_error(errno, p, *existing, ec, "boost::filesystem::create_directory");
+            return false;
+        }
+#endif
+
+        const mode_t existing_mode = get_mode(existing_stat);
+        if (!S_ISDIR(existing_mode))
+        {
+            emit_error(ENOTDIR, p, *existing, ec, "boost::filesystem::create_directory");
+            return false;
+        }
+
+        mode = existing_mode;
+    }
+
+    if (::mkdir(p.c_str(), mode) == 0)
+        return true;
+
+#else // defined(BOOST_POSIX_API)
+
+    BOOL res;
+    if (existing)
+        res = ::CreateDirectoryExW(existing->c_str(), p.c_str(), nullptr);
+    else
+        res = ::CreateDirectoryW(p.c_str(), nullptr);
+
+    if (res)
+        return true;
+
+#endif // defined(BOOST_POSIX_API)
+
+    //  attempt to create directory failed
+    err_t errval = BOOST_ERRNO; // save reason for failure
+    error_code dummy;
+
+    if (is_directory(p, dummy))
+        return false;
+
+    //  attempt to create directory failed && it doesn't already exist
+    emit_error(errval, p, ec, "boost::filesystem::create_directory");
+    return false;
+}
+
+BOOST_FILESYSTEM_DECL
+void create_directory_symlink(path const& to, path const& from, system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+    int err = ::symlink(to.c_str(), from.c_str());
+    if (BOOST_UNLIKELY(err < 0))
+    {
+        err = errno;
+        emit_error(err, to, from, ec, "boost::filesystem::create_directory_symlink");
+    }
+#else
+    // see if actually supported by Windows runtime dll
+    if (!create_symbolic_link_api)
+    {
+        emit_error(BOOST_ERROR_NOT_SUPPORTED, to, from, ec, "boost::filesystem::create_directory_symlink");
+        return;
+    }
+
+    if (!create_symbolic_link_api(from.c_str(), to.c_str(), SYMBOLIC_LINK_FLAG_DIRECTORY | SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE))
+    {
+        emit_error(BOOST_ERRNO, to, from, ec, "boost::filesystem::create_directory_symlink");
+    }
+#endif
+}
+
+BOOST_FILESYSTEM_DECL
+void create_hard_link(path const& to, path const& from, error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+    int err = ::link(to.c_str(), from.c_str());
+    if (BOOST_UNLIKELY(err < 0))
+    {
+        err = errno;
+        emit_error(err, to, from, ec, "boost::filesystem::create_hard_link");
+    }
+#else
+    // see if actually supported by Windows runtime dll
+    CreateHardLinkW_t* chl_api = filesystem::detail::atomic_load_relaxed(create_hard_link_api);
+    if (BOOST_UNLIKELY(!chl_api))
+    {
+        emit_error(BOOST_ERROR_NOT_SUPPORTED, to, from, ec, "boost::filesystem::create_hard_link");
+        return;
+    }
+
+    if (BOOST_UNLIKELY(!chl_api(from.c_str(), to.c_str(), nullptr)))
+    {
+        emit_error(BOOST_ERRNO, to, from, ec, "boost::filesystem::create_hard_link");
+    }
+#endif
+}
+
+BOOST_FILESYSTEM_DECL
+void create_symlink(path const& to, path const& from, error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+    int err = ::symlink(to.c_str(), from.c_str());
+    if (BOOST_UNLIKELY(err < 0))
+    {
+        err = errno;
+        emit_error(err, to, from, ec, "boost::filesystem::create_symlink");
+    }
+#else
+    // see if actually supported by Windows runtime dll
+    CreateSymbolicLinkW_t* csl_api = filesystem::detail::atomic_load_relaxed(create_symbolic_link_api);
+    if (BOOST_UNLIKELY(!csl_api))
+    {
+        emit_error(BOOST_ERROR_NOT_SUPPORTED, to, from, ec, "boost::filesystem::create_symlink");
+        return;
+    }
+
+    if (BOOST_UNLIKELY(!csl_api(from.c_str(), to.c_str(), SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE)))
+    {
+        emit_error(BOOST_ERRNO, to, from, ec, "boost::filesystem::create_symlink");
+    }
+#endif
+}
+
+BOOST_FILESYSTEM_DECL
+path current_path(error_code* ec)
+{
+#if defined(BOOST_FILESYSTEM_USE_WASI)
+    // Windows CE has no current directory, so everything's relative to the root of the directory tree.
+    // WASI also does not support current path.
+    emit_error(BOOST_ERROR_NOT_SUPPORTED, ec, "boost::filesystem::current_path");
+    return path();
+#elif defined(BOOST_POSIX_API)
+    struct local
+    {
+        static bool getcwd_error(error_code* ec)
+        {
+            const int err = errno;
+            return error((err != ERANGE
+#if defined(__MSL__) && (defined(macintosh) || defined(__APPLE__) || defined(__APPLE_CC__))
+                          // bug in some versions of the Metrowerks C lib on the Mac: wrong errno set
+                          && err != 0
+#endif
+                          ) ? err : 0,
+                         ec, "boost::filesystem::current_path");
+        }
+    };
+
+    path cur;
+    char small_buf[small_path_size];
+    const char* p = ::getcwd(small_buf, sizeof(small_buf));
+    if (BOOST_LIKELY(!!p))
+    {
+        cur = p;
+        if (ec)
+            ec->clear();
+    }
+    else if (BOOST_LIKELY(!local::getcwd_error(ec)))
+    {
+        for (std::size_t path_max = sizeof(small_buf) * 2u;; path_max *= 2u) // loop 'til buffer large enough
+        {
+            if (BOOST_UNLIKELY(path_max > absolute_path_max))
+            {
+                emit_error(ENAMETOOLONG, ec, "boost::filesystem::current_path");
+                break;
+            }
+
+            std::unique_ptr< char[] > buf(new char[path_max]);
+            p = ::getcwd(buf.get(), path_max);
+            if (BOOST_LIKELY(!!p))
+            {
+                cur = buf.get();
+                if (ec)
+                    ec->clear();
+                break;
+            }
+            else if (BOOST_UNLIKELY(local::getcwd_error(ec)))
+            {
+                break;
+            }
+        }
+    }
+
+    return cur;
+#else
+    DWORD sz;
+    if ((sz = ::GetCurrentDirectoryW(0, nullptr)) == 0)
+        sz = 1;
+    std::unique_ptr< path::value_type[] > buf(new path::value_type[sz]);
+    error(::GetCurrentDirectoryW(sz, buf.get()) == 0 ? BOOST_ERRNO : 0, ec, "boost::filesystem::current_path");
+    return path(buf.get());
+#endif
+}
+
+BOOST_FILESYSTEM_DECL
+void current_path(path const& p, system::error_code* ec)
+{
+#if defined(BOOST_FILESYSTEM_USE_WASI)
+    emit_error(BOOST_ERROR_NOT_SUPPORTED, p, ec, "boost::filesystem::current_path");
+#else
+    error(!BOOST_SET_CURRENT_DIRECTORY(p.c_str()) ? BOOST_ERRNO : 0, p, ec, "boost::filesystem::current_path");
+#endif
+}
+
+BOOST_FILESYSTEM_DECL
+bool equivalent_v3(path const& p1, path const& p2, system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+
+    // p2 is done first, so any error reported is for p1
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    struct ::statx s2;
+    int e2 = invoke_statx(AT_FDCWD, p2.c_str(), AT_NO_AUTOMOUNT, STATX_INO, &s2);
+    if (BOOST_LIKELY(e2 == 0))
+    {
+        if (BOOST_UNLIKELY((s2.stx_mask & STATX_INO) != STATX_INO))
+        {
+        fail_unsupported:
+            emit_error(BOOST_ERROR_NOT_SUPPORTED, p1, p2, ec, "boost::filesystem::equivalent");
+            return false;
+        }
+    }
+
+    struct ::statx s1;
+    int e1 = invoke_statx(AT_FDCWD, p1.c_str(), AT_NO_AUTOMOUNT, STATX_INO, &s1);
+    if (BOOST_LIKELY(e1 == 0))
+    {
+        if (BOOST_UNLIKELY((s1.stx_mask & STATX_INO) != STATX_INO))
+            goto fail_unsupported;
+    }
+#else
+    struct ::stat s2;
+    int e2 = ::stat(p2.c_str(), &s2);
+    struct ::stat s1;
+    int e1 = ::stat(p1.c_str(), &s1);
+#endif
+
+    if (BOOST_UNLIKELY(e1 != 0 || e2 != 0))
+    {
+        // if one is invalid and the other isn't then they aren't equivalent,
+        // but if both are invalid then it is an error
+        if (e1 != 0 && e2 != 0)
+        {
+            int err = errno;
+            emit_error(err, p1, p2, ec, "boost::filesystem::equivalent");
+        }
+        return false;
+    }
+
+    return equivalent_stat(s1, s2);
+
+#else // Windows
+
+    // Thanks to Jeremy Maitin-Shepard for much help and for permission to
+    // base the equivalent() implementation on portions of his
+    // file-equivalence-win32.cpp experimental code.
+
+    // Note well: Physical location on external media is part of the
+    // equivalence criteria. If there are no open handles, physical location
+    // can change due to defragmentation or other relocations. Thus handles
+    // must be held open until location information for both paths has
+    // been retrieved.
+
+    // p2 is done first, so any error reported is for p1
+    unique_handle h2(create_file_handle(
+        p2.c_str(),
+        FILE_READ_ATTRIBUTES,
+        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS));
+
+    unique_handle h1(create_file_handle(
+        p1.c_str(),
+        FILE_READ_ATTRIBUTES,
+        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS));
+
+    if (BOOST_UNLIKELY(!h1 || !h2))
+    {
+        // if one is invalid and the other isn't, then they aren't equivalent,
+        // but if both are invalid then it is an error
+        if (!h1 && !h2)
+            error(BOOST_ERRNO, p1, p2, ec, "boost::filesystem::equivalent");
+        return false;
+    }
+
+    // at this point, both handles are known to be valid
+
+    BY_HANDLE_FILE_INFORMATION info1, info2;
+
+    if (error(!::GetFileInformationByHandle(h1.get(), &info1) ? BOOST_ERRNO : 0, p1, p2, ec, "boost::filesystem::equivalent"))
+        return false;
+
+    if (error(!::GetFileInformationByHandle(h2.get(), &info2) ? BOOST_ERRNO : 0, p1, p2, ec, "boost::filesystem::equivalent"))
+        return false;
+
+    // In theory, volume serial numbers are sufficient to distinguish between
+    // devices, but in practice VSN's are sometimes duplicated, so last write
+    // time and file size are also checked.
+    return info1.dwVolumeSerialNumber == info2.dwVolumeSerialNumber &&
+        info1.nFileIndexHigh == info2.nFileIndexHigh &&
+        info1.nFileIndexLow == info2.nFileIndexLow &&
+        info1.nFileSizeHigh == info2.nFileSizeHigh &&
+        info1.nFileSizeLow == info2.nFileSizeLow &&
+        info1.ftLastWriteTime.dwLowDateTime == info2.ftLastWriteTime.dwLowDateTime &&
+        info1.ftLastWriteTime.dwHighDateTime == info2.ftLastWriteTime.dwHighDateTime;
+
+#endif
+}
+
+BOOST_FILESYSTEM_DECL
+bool equivalent_v4(path const& p1, path const& p2, system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    struct ::statx s1;
+    int err = invoke_statx(AT_FDCWD, p1.c_str(), AT_NO_AUTOMOUNT, STATX_INO, &s1);
+    if (BOOST_UNLIKELY(err != 0))
+    {
+    fail_errno:
+        err = errno;
+    fail_err:
+        emit_error(err, p1, p2, ec, "boost::filesystem::equivalent");
+        return false;
+    }
+
+    if (BOOST_UNLIKELY((s1.stx_mask & STATX_INO) != STATX_INO))
+    {
+    fail_unsupported:
+        err = BOOST_ERROR_NOT_SUPPORTED;
+        goto fail_err;
+    }
+
+    struct ::statx s2;
+    err = invoke_statx(AT_FDCWD, p2.c_str(), AT_NO_AUTOMOUNT, STATX_INO, &s2);
+    if (BOOST_UNLIKELY(err != 0))
+        goto fail_errno;
+
+    if (BOOST_UNLIKELY((s1.stx_mask & STATX_INO) != STATX_INO))
+        goto fail_unsupported;
+#else
+    struct ::stat s1;
+    int err = ::stat(p1.c_str(), &s1);
+    if (BOOST_UNLIKELY(err != 0))
+    {
+    fail_errno:
+        err = errno;
+        emit_error(err, p1, p2, ec, "boost::filesystem::equivalent");
+        return false;
+    }
+
+    struct ::stat s2;
+    err = ::stat(p2.c_str(), &s2);
+    if (BOOST_UNLIKELY(err != 0))
+        goto fail_errno;
+#endif
+
+    return equivalent_stat(s1, s2);
+
+#else // Windows
+
+    // Thanks to Jeremy Maitin-Shepard for much help and for permission to
+    // base the equivalent() implementation on portions of his
+    // file-equivalence-win32.cpp experimental code.
+
+    // Note well: Physical location on external media is part of the
+    // equivalence criteria. If there are no open handles, physical location
+    // can change due to defragmentation or other relocations. Thus handles
+    // must be held open until location information for both paths has
+    // been retrieved.
+
+    unique_handle h1(create_file_handle(
+        p1.c_str(),
+        FILE_READ_ATTRIBUTES,
+        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS));
+    if (BOOST_UNLIKELY(!h1))
+    {
+    fail_errno:
+        err_t err = BOOST_ERRNO;
+        emit_error(err, p1, p2, ec, "boost::filesystem::equivalent");
+        return false;
+    }
+
+    unique_handle h2(create_file_handle(
+        p2.c_str(),
+        FILE_READ_ATTRIBUTES,
+        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS));
+    if (BOOST_UNLIKELY(!h2))
+        goto fail_errno;
+
+    BY_HANDLE_FILE_INFORMATION info1;
+    if (BOOST_UNLIKELY(!::GetFileInformationByHandle(h1.get(), &info1)))
+        goto fail_errno;
+
+    BY_HANDLE_FILE_INFORMATION info2;
+    if (BOOST_UNLIKELY(!::GetFileInformationByHandle(h2.get(), &info2)))
+        goto fail_errno;
+
+    // In theory, volume serial numbers are sufficient to distinguish between
+    // devices, but in practice VSN's are sometimes duplicated, so last write
+    // time and file size are also checked.
+    return info1.dwVolumeSerialNumber == info2.dwVolumeSerialNumber &&
+        info1.nFileIndexHigh == info2.nFileIndexHigh &&
+        info1.nFileIndexLow == info2.nFileIndexLow &&
+        info1.nFileSizeHigh == info2.nFileSizeHigh &&
+        info1.nFileSizeLow == info2.nFileSizeLow &&
+        info1.ftLastWriteTime.dwLowDateTime == info2.ftLastWriteTime.dwLowDateTime &&
+        info1.ftLastWriteTime.dwHighDateTime == info2.ftLastWriteTime.dwHighDateTime;
+
+#endif
+}
+
+BOOST_FILESYSTEM_DECL
+uintmax_t file_size(path const& p, error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    struct ::statx path_stat;
+    int err;
+    if (BOOST_UNLIKELY(invoke_statx(AT_FDCWD, p.c_str(), AT_NO_AUTOMOUNT, STATX_TYPE | STATX_SIZE, &path_stat) < 0))
+    {
+        err = errno;
+    fail:
+        emit_error(err, p, ec, "boost::filesystem::file_size");
+        return static_cast< uintmax_t >(-1);
+    }
+
+    if (BOOST_UNLIKELY((path_stat.stx_mask & (STATX_TYPE | STATX_SIZE)) != (STATX_TYPE | STATX_SIZE) || !S_ISREG(path_stat.stx_mode)))
+    {
+        err = BOOST_ERROR_NOT_SUPPORTED;
+        goto fail;
+    }
+#else
+    struct ::stat path_stat;
+    int err;
+    if (BOOST_UNLIKELY(::stat(p.c_str(), &path_stat) < 0))
+    {
+        err = errno;
+    fail:
+        emit_error(err, p, ec, "boost::filesystem::file_size");
+        return static_cast< uintmax_t >(-1);
+    }
+
+    if (BOOST_UNLIKELY(!S_ISREG(path_stat.st_mode)))
+    {
+        err = BOOST_ERROR_NOT_SUPPORTED;
+        goto fail;
+    }
+#endif
+
+    return get_size(path_stat);
+
+#else // defined(BOOST_POSIX_API)
+
+    // assume uintmax_t is 64-bits on all Windows compilers
+
+    unique_handle h(create_file_handle(
+        p.c_str(),
+        FILE_READ_ATTRIBUTES,
+        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS));
+
+    DWORD err;
+    if (BOOST_UNLIKELY(!h))
+    {
+    fail_errno:
+        err = BOOST_ERRNO;
+    fail:
+        emit_error(err, p, ec, "boost::filesystem::file_size");
+        return static_cast< uintmax_t >(-1);
+    }
+
+    BY_HANDLE_FILE_INFORMATION info;
+    if (BOOST_UNLIKELY(!::GetFileInformationByHandle(h.get(), &info)))
+        goto fail_errno;
+
+    if (BOOST_UNLIKELY((info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0u))
+    {
+        err = ERROR_NOT_SUPPORTED;
+        goto fail;
+    }
+
+    return (static_cast< uintmax_t >(info.nFileSizeHigh) << 32u) | info.nFileSizeLow;
+
+#endif // defined(BOOST_POSIX_API)
+}
+
+BOOST_FILESYSTEM_DECL
+uintmax_t hard_link_count(path const& p, system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    struct ::statx path_stat;
+    if (BOOST_UNLIKELY(invoke_statx(AT_FDCWD, p.c_str(), AT_NO_AUTOMOUNT, STATX_NLINK, &path_stat) < 0))
+    {
+        emit_error(errno, p, ec, "boost::filesystem::hard_link_count");
+        return static_cast< uintmax_t >(-1);
+    }
+
+    if (BOOST_UNLIKELY((path_stat.stx_mask & STATX_NLINK) != STATX_NLINK))
+    {
+        emit_error(BOOST_ERROR_NOT_SUPPORTED, p, ec, "boost::filesystem::hard_link_count");
+        return static_cast< uintmax_t >(-1);
+    }
+
+    return static_cast< uintmax_t >(path_stat.stx_nlink);
+#else
+    struct ::stat path_stat;
+    if (BOOST_UNLIKELY(::stat(p.c_str(), &path_stat) < 0))
+    {
+        emit_error(errno, p, ec, "boost::filesystem::hard_link_count");
+        return static_cast< uintmax_t >(-1);
+    }
+
+    return static_cast< uintmax_t >(path_stat.st_nlink);
+#endif
+
+#else // defined(BOOST_POSIX_API)
+
+    unique_handle h(create_file_handle(
+        p.c_str(),
+        FILE_READ_ATTRIBUTES,
+        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS));
+
+    if (BOOST_UNLIKELY(!h))
+    {
+    fail_errno:
+        emit_error(BOOST_ERRNO, p, ec, "boost::filesystem::hard_link_count");
+        return static_cast< uintmax_t >(-1);
+    }
+
+    // Link count info is only available through GetFileInformationByHandle
+    BY_HANDLE_FILE_INFORMATION info;
+    if (BOOST_UNLIKELY(!::GetFileInformationByHandle(h.get(), &info)))
+        goto fail_errno;
+
+    return static_cast< uintmax_t >(info.nNumberOfLinks);
+
+#endif // defined(BOOST_POSIX_API)
+}
+
+BOOST_FILESYSTEM_DECL
+path initial_path(error_code* ec)
+{
+    static path init_path;
+    if (init_path.empty())
+        init_path = current_path(ec);
+    else if (ec)
+        ec->clear();
+    return init_path;
+}
+
+//! Tests if the directory is empty. Implemented in directory.cpp.
+bool is_empty_directory
+(
+#if defined(BOOST_POSIX_API)
+    boost::scope::unique_fd&& fd,
+#else
+    unique_handle&& h,
+#endif
+    path const& p,
+    error_code* ec
+);
+
+BOOST_FILESYSTEM_DECL
+bool is_empty(path const& p, system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+
+    boost::scope::unique_fd file;
+    int err = 0;
+    while (true)
+    {
+        file.reset(::open(p.c_str(), O_RDONLY | O_CLOEXEC));
+        if (BOOST_UNLIKELY(!file))
+        {
+            err = errno;
+            if (err == EINTR)
+                continue;
+
+        fail:
+            emit_error(err, p, ec, "boost::filesystem::is_empty");
+            return false;
+        }
+
+        break;
+    }
+
+#if defined(BOOST_FILESYSTEM_NO_O_CLOEXEC) && defined(FD_CLOEXEC)
+    if (BOOST_UNLIKELY(::fcntl(file.get(), F_SETFD, FD_CLOEXEC) < 0))
+    {
+        err = errno;
+        goto fail;
+    }
+#endif
+
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    struct ::statx path_stat;
+    if (BOOST_UNLIKELY(invoke_statx(file.get(), "", AT_EMPTY_PATH | AT_NO_AUTOMOUNT, STATX_TYPE | STATX_SIZE, &path_stat) < 0))
+    {
+        err = errno;
+        goto fail;
+    }
+
+    if (BOOST_UNLIKELY((path_stat.stx_mask & (STATX_TYPE | STATX_SIZE)) != (STATX_TYPE | STATX_SIZE)))
+    {
+        err = BOOST_ERROR_NOT_SUPPORTED;
+        goto fail;
+    }
+#else
+    struct ::stat path_stat;
+    if (BOOST_UNLIKELY(::fstat(file.get(), &path_stat) < 0))
+    {
+        err = errno;
+        goto fail;
+    }
+#endif
+
+    const mode_t mode = get_mode(path_stat);
+    if (S_ISDIR(mode))
+        return is_empty_directory(std::move(file), p, ec);
+
+    if (BOOST_UNLIKELY(!S_ISREG(mode)))
+    {
+        err = BOOST_ERROR_NOT_SUPPORTED;
+        goto fail;
+    }
+
+    return get_size(path_stat) == 0u;
+
+#else // defined(BOOST_POSIX_API)
+
+    unique_handle h(create_file_handle(
+        p.c_str(),
+        FILE_READ_ATTRIBUTES | FILE_LIST_DIRECTORY,
+        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS));
+
+    if (BOOST_UNLIKELY(!h))
+    {
+    fail_errno:
+        const DWORD err = BOOST_ERRNO;
+        emit_error(err, p, ec, "boost::filesystem::is_empty");
+        return false;
+    }
+
+    BY_HANDLE_FILE_INFORMATION info;
+    if (BOOST_UNLIKELY(!::GetFileInformationByHandle(h.get(), &info)))
+        goto fail_errno;
+
+    if ((info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0u)
+        return is_empty_directory(std::move(h), p, ec);
+
+    return (info.nFileSizeHigh | info.nFileSizeLow) == 0u;
+
+#endif // defined(BOOST_POSIX_API)
+}
+
+BOOST_FILESYSTEM_DECL
+std::time_t creation_time(path const& p, system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    struct ::statx stx;
+    if (BOOST_UNLIKELY(invoke_statx(AT_FDCWD, p.c_str(), AT_NO_AUTOMOUNT, STATX_BTIME, &stx) < 0))
+    {
+        emit_error(BOOST_ERRNO, p, ec, "boost::filesystem::creation_time");
+        return (std::numeric_limits< std::time_t >::min)();
+    }
+    if (BOOST_UNLIKELY((stx.stx_mask & STATX_BTIME) != STATX_BTIME))
+    {
+        emit_error(BOOST_ERROR_NOT_SUPPORTED, p, ec, "boost::filesystem::creation_time");
+        return (std::numeric_limits< std::time_t >::min)();
+    }
+    return stx.stx_btime.tv_sec;
+#elif defined(BOOST_FILESYSTEM_STAT_ST_BIRTHTIME) && defined(BOOST_FILESYSTEM_STAT_ST_BIRTHTIMENSEC)
+    struct ::stat st;
+    if (BOOST_UNLIKELY(::stat(p.c_str(), &st) < 0))
+    {
+        emit_error(BOOST_ERRNO, p, ec, "boost::filesystem::creation_time");
+        return (std::numeric_limits< std::time_t >::min)();
+    }
+    return st.BOOST_FILESYSTEM_STAT_ST_BIRTHTIME;
+#else
+    emit_error(BOOST_ERROR_NOT_SUPPORTED, p, ec, "boost::filesystem::creation_time");
+    return (std::numeric_limits< std::time_t >::min)();
+#endif
+
+#else // defined(BOOST_POSIX_API)
+
+    // See the comment in last_write_time regarding access rights used here for GetFileTime.
+    unique_handle hw(create_file_handle(
+        p.c_str(),
+        FILE_READ_ATTRIBUTES | FILE_READ_EA,
+        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS));
+
+    DWORD err;
+    if (BOOST_UNLIKELY(!hw))
+    {
+    fail_errno:
+        err = BOOST_ERRNO;
+    fail:
+        emit_error(err, p, ec, "boost::filesystem::creation_time");
+        return (std::numeric_limits< std::time_t >::min)();
+    }
+
+    FILETIME ct;
+    if (BOOST_UNLIKELY(!::GetFileTime(hw.get(), &ct, nullptr, nullptr)))
+        goto fail_errno;
+
+    std::time_t t;
+    err = to_time_t(ct, t);
+    if (BOOST_UNLIKELY(err != 0u))
+        goto fail;
+
+    return t;
+
+#endif // defined(BOOST_POSIX_API)
+}
+
+BOOST_FILESYSTEM_DECL
+std::time_t last_write_time(path const& p, system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+
+#if defined(BOOST_FILESYSTEM_USE_STATX)
+    struct ::statx stx;
+    if (BOOST_UNLIKELY(invoke_statx(AT_FDCWD, p.c_str(), AT_NO_AUTOMOUNT, STATX_MTIME, &stx) < 0))
+    {
+        emit_error(BOOST_ERRNO, p, ec, "boost::filesystem::last_write_time");
+        return (std::numeric_limits< std::time_t >::min)();
+    }
+    if (BOOST_UNLIKELY((stx.stx_mask & STATX_MTIME) != STATX_MTIME))
+    {
+        emit_error(BOOST_ERROR_NOT_SUPPORTED, p, ec, "boost::filesystem::last_write_time");
+        return (std::numeric_limits< std::time_t >::min)();
+    }
+    return stx.stx_mtime.tv_sec;
+#else
+    struct ::stat st;
+    if (BOOST_UNLIKELY(::stat(p.c_str(), &st) < 0))
+    {
+        emit_error(BOOST_ERRNO, p, ec, "boost::filesystem::last_write_time");
+        return (std::numeric_limits< std::time_t >::min)();
+    }
+    return st.st_mtime;
+#endif
+
+#else // defined(BOOST_POSIX_API)
+
+    // GetFileTime is documented to require GENERIC_READ access right, but this causes problems if the file
+    // is opened by another process without FILE_SHARE_READ. In practice, FILE_READ_ATTRIBUTES works, and
+    // FILE_READ_EA is also added for good measure, in case if it matters for SMBv1.
+    unique_handle hw(create_file_handle(
+        p.c_str(),
+        FILE_READ_ATTRIBUTES | FILE_READ_EA,
+        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS));
+
+    DWORD err;
+    if (BOOST_UNLIKELY(!hw))
+    {
+    fail_errno:
+        err = BOOST_ERRNO;
+    fail:
+        emit_error(err, p, ec, "boost::filesystem::last_write_time");
+        return (std::numeric_limits< std::time_t >::min)();
+    }
+
+    FILETIME lwt;
+    if (BOOST_UNLIKELY(!::GetFileTime(hw.get(), nullptr, nullptr, &lwt)))
+        goto fail_errno;
+
+    std::time_t t;
+    err = to_time_t(lwt, t);
+    if (BOOST_UNLIKELY(err != 0u))
+        goto fail;
+
+    return t;
+
+#endif // defined(BOOST_POSIX_API)
+}
+
+BOOST_FILESYSTEM_DECL
+void last_write_time(path const& p, const std::time_t new_time, system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_POSIX_API)
+
+#if defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+
+    struct timespec times[2] = {};
+
+    // Keep the last access time unchanged
+    times[0].tv_nsec = UTIME_OMIT;
+
+    times[1].tv_sec = new_time;
+
+    if (BOOST_UNLIKELY(::utimensat(AT_FDCWD, p.c_str(), times, 0) != 0))
+    {
+        emit_error(BOOST_ERRNO, p, ec, "boost::filesystem::last_write_time");
+        return;
+    }
+
+#else // defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+
+    struct ::stat st;
+    if (BOOST_UNLIKELY(::stat(p.c_str(), &st) < 0))
+    {
+        emit_error(BOOST_ERRNO, p, ec, "boost::filesystem::last_write_time");
+        return;
+    }
+
+    ::utimbuf buf;
+    buf.actime = st.st_atime; // utime() updates access time too :-(
+    buf.modtime = new_time;
+    if (BOOST_UNLIKELY(::utime(p.c_str(), &buf) < 0))
+        emit_error(BOOST_ERRNO, p, ec, "boost::filesystem::last_write_time");
+
+#endif // defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+
+#else // defined(BOOST_POSIX_API)
+
+    unique_handle hw(create_file_handle(
+        p.c_str(),
+        FILE_WRITE_ATTRIBUTES,
+        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS));
+
+    DWORD err;
+    if (BOOST_UNLIKELY(!hw))
+    {
+    fail_errno:
+        err = BOOST_ERRNO;
+    fail:
+        emit_error(err, p, ec, "boost::filesystem::last_write_time");
+        return;
+    }
+
+    FILETIME lwt;
+    err = to_FILETIME(new_time, lwt);
+    if (BOOST_UNLIKELY(err != 0u))
+        goto fail;
+
+    if (BOOST_UNLIKELY(!::SetFileTime(hw.get(), nullptr, nullptr, &lwt)))
+        goto fail_errno;
+
+#endif // defined(BOOST_POSIX_API)
+}
+
+#ifdef BOOST_POSIX_API
+const perms active_bits(all_all | set_uid_on_exe | set_gid_on_exe | sticky_bit);
+inline mode_t mode_cast(perms prms)
+{
+    return prms & active_bits;
+}
+#endif
+
+BOOST_FILESYSTEM_DECL
+void permissions(path const& p, perms prms, system::error_code* ec)
+{
+    BOOST_ASSERT_MSG(!((prms & add_perms) && (prms & remove_perms)), "add_perms and remove_perms are mutually exclusive");
+
+    if ((prms & add_perms) && (prms & remove_perms)) // precondition failed
+        return;
+
+#if defined(BOOST_FILESYSTEM_USE_WASI)
+    emit_error(BOOST_ERROR_NOT_SUPPORTED, p, ec, "boost::filesystem::permissions");
+#elif defined(BOOST_POSIX_API)
+    error_code local_ec;
+    file_status current_status((prms & symlink_perms) ? detail::symlink_status_impl(p, &local_ec) : detail::status_impl(p, &local_ec));
+    if (local_ec)
+    {
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::permissions", p, local_ec));
+
+        *ec = local_ec;
+        return;
+    }
+
+    if (prms & add_perms)
+        prms |= current_status.permissions();
+    else if (prms & remove_perms)
+        prms = current_status.permissions() & ~prms;
+
+    // OS X <10.10, iOS <8.0 and some other platforms don't support fchmodat().
+    // Solaris (SunPro and gcc) only support fchmodat() on Solaris 11 and higher,
+    // and a runtime check is too much trouble.
+    // Linux does not support permissions on symbolic links and has no plans to
+    // support them in the future.  The chmod() code is thus more practical,
+    // rather than always hitting ENOTSUP when sending in AT_SYMLINK_NO_FOLLOW.
+    //  - See the 3rd paragraph of
+    // "Symbolic link ownership, permissions, and timestamps" at:
+    //   "http://man7.org/linux/man-pages/man7/symlink.7.html"
+    //  - See the fchmodat() Linux man page:
+    //   "http://man7.org/linux/man-pages/man2/fchmodat.2.html"
+#if defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS) && \
+    !(defined(__SUNPRO_CC) || defined(__sun) || defined(sun)) && \
+    !(defined(linux) || defined(__linux) || defined(__linux__)) && \
+    !(defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && __MAC_OS_X_VERSION_MIN_REQUIRED < 101000) && \
+    !(defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && __IPHONE_OS_VERSION_MIN_REQUIRED < 80000) && \
+    !(defined(__rtems__)) && \
+    !(defined(__QNX__) && (_NTO_VERSION <= 700))
+    if (::fchmodat(AT_FDCWD, p.c_str(), mode_cast(prms), !(prms & symlink_perms) ? 0 : AT_SYMLINK_NOFOLLOW))
+#else // fallback if fchmodat() not supported
+    if (::chmod(p.c_str(), mode_cast(prms)))
+#endif
+    {
+        const int err = errno;
+        if (!ec)
+        {
+            BOOST_FILESYSTEM_THROW(filesystem_error(
+                "boost::filesystem::permissions", p, error_code(err, system::generic_category())));
+        }
+
+        ec->assign(err, system::generic_category());
+    }
+
+#else // Windows
+
+    // if not going to alter FILE_ATTRIBUTE_READONLY, just return
+    if (!(!((prms & (add_perms | remove_perms))) || (prms & (owner_write | group_write | others_write))))
+        return;
+
+    DWORD attr = ::GetFileAttributesW(p.c_str());
+
+    if (error(attr == 0 ? BOOST_ERRNO : 0, p, ec, "boost::filesystem::permissions"))
+        return;
+
+    if (prms & add_perms)
+        attr &= ~FILE_ATTRIBUTE_READONLY;
+    else if (prms & remove_perms)
+        attr |= FILE_ATTRIBUTE_READONLY;
+    else if (prms & (owner_write | group_write | others_write))
+        attr &= ~FILE_ATTRIBUTE_READONLY;
+    else
+        attr |= FILE_ATTRIBUTE_READONLY;
+
+    error(::SetFileAttributesW(p.c_str(), attr) == 0 ? BOOST_ERRNO : 0, p, ec, "boost::filesystem::permissions");
+#endif
+}
+
+BOOST_FILESYSTEM_DECL
+path read_symlink(path const& p, system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+    path symlink_path;
+
+#ifdef BOOST_POSIX_API
+    const char* const path_str = p.c_str();
+    char small_buf[small_path_size];
+    ssize_t result = ::readlink(path_str, small_buf, sizeof(small_buf));
+    if (BOOST_UNLIKELY(result < 0))
+    {
+    fail:
+        const int err = errno;
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::read_symlink", p, error_code(err, system_category())));
+
+        ec->assign(err, system_category());
+    }
+    else if (BOOST_LIKELY(static_cast< std::size_t >(result) < sizeof(small_buf)))
+    {
+        symlink_path.assign(small_buf, small_buf + result);
+    }
+    else
+    {
+        for (std::size_t path_max = sizeof(small_buf) * 2u;; path_max *= 2u) // loop 'til buffer large enough
+        {
+            if (BOOST_UNLIKELY(path_max > absolute_path_max))
+            {
+                if (!ec)
+                    BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::read_symlink", p, error_code(ENAMETOOLONG, system_category())));
+
+                ec->assign(ENAMETOOLONG, system_category());
+                break;
+            }
+
+            std::unique_ptr< char[] > buf(new char[path_max]);
+            result = ::readlink(path_str, buf.get(), path_max);
+            if (BOOST_UNLIKELY(result < 0))
+            {
+                goto fail;
+            }
+            else if (BOOST_LIKELY(static_cast< std::size_t >(result) < path_max))
+            {
+                symlink_path.assign(buf.get(), buf.get() + result);
+                break;
+            }
+        }
+    }
+
+#else
+
+    unique_handle h(create_file_handle(
+        p.c_str(),
+        FILE_READ_ATTRIBUTES,
+        FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+        nullptr,
+        OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT));
+
+    DWORD error;
+    if (BOOST_UNLIKELY(!h))
+    {
+    return_last_error:
+        error = ::GetLastError();
+        emit_error(error, p, ec, "boost::filesystem::read_symlink");
+        return symlink_path;
+    }
+
+    std::unique_ptr< reparse_data_buffer_with_storage > buf(new reparse_data_buffer_with_storage);
+    DWORD sz = 0u;
+    if (BOOST_UNLIKELY(!::DeviceIoControl(h.get(), FSCTL_GET_REPARSE_POINT, nullptr, 0, buf.get(), sizeof(*buf), &sz, nullptr)))
+        goto return_last_error;
+
+    const wchar_t* buffer;
+    std::size_t offset, len;
+    switch (buf->rdb.ReparseTag)
+    {
+    case IO_REPARSE_TAG_MOUNT_POINT:
+        buffer = buf->rdb.MountPointReparseBuffer.PathBuffer;
+        offset = buf->rdb.MountPointReparseBuffer.SubstituteNameOffset;
+        len = buf->rdb.MountPointReparseBuffer.SubstituteNameLength;
+        break;
+
+    case IO_REPARSE_TAG_SYMLINK:
+        buffer = buf->rdb.SymbolicLinkReparseBuffer.PathBuffer;
+        offset = buf->rdb.SymbolicLinkReparseBuffer.SubstituteNameOffset;
+        len = buf->rdb.SymbolicLinkReparseBuffer.SubstituteNameLength;
+        // Note: iff info.rdb.SymbolicLinkReparseBuffer.Flags & SYMLINK_FLAG_RELATIVE
+        //       -> resulting path is relative to the source
+        break;
+
+    default:
+        emit_error(BOOST_ERROR_NOT_SUPPORTED, p, ec, "Unknown ReparseTag in boost::filesystem::read_symlink");
+        return symlink_path;
+    }
+
+    symlink_path = convert_nt_path_to_win32_path(buffer + offset / sizeof(wchar_t), len / sizeof(wchar_t));
+#endif
+
+    return symlink_path;
+}
+
+BOOST_FILESYSTEM_DECL
+path relative(path const& p, path const& base, error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+    error_code local_ec;
+    path cur_path;
+    if (!p.is_absolute() || !base.is_absolute())
+    {
+        cur_path = detail::current_path(&local_ec);
+        if (BOOST_UNLIKELY(!!local_ec))
+        {
+        fail_local_ec:
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::relative", p, base, local_ec));
+
+            *ec = local_ec;
+            return path();
+        }
+    }
+
+    path wc_base(detail::weakly_canonical_v4(base, cur_path, &local_ec));
+    if (BOOST_UNLIKELY(!!local_ec))
+        goto fail_local_ec;
+    path wc_p(detail::weakly_canonical_v4(p, cur_path, &local_ec));
+    if (BOOST_UNLIKELY(!!local_ec))
+        goto fail_local_ec;
+    return wc_p.lexically_relative(wc_base);
+}
+
+BOOST_FILESYSTEM_DECL
+bool remove(path const& p, error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+    return detail::remove_impl(p, ec);
+}
+
+BOOST_FILESYSTEM_DECL
+uintmax_t remove_all(path const& p, error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+    return detail::remove_all_impl(p, ec);
+}
+
+BOOST_FILESYSTEM_DECL
+void rename(path const& old_p, path const& new_p, error_code* ec)
+{
+    error(!BOOST_MOVE_FILE(old_p.c_str(), new_p.c_str()) ? BOOST_ERRNO : 0, old_p, new_p, ec, "boost::filesystem::rename");
+}
+
+BOOST_FILESYSTEM_DECL
+void resize_file(path const& p, uintmax_t size, system::error_code* ec)
+{
+#if defined(BOOST_POSIX_API)
+    if (BOOST_UNLIKELY(size > static_cast< uintmax_t >((std::numeric_limits< off_t >::max)())))
+    {
+        emit_error(system::errc::file_too_large, p, ec, "boost::filesystem::resize_file");
+        return;
+    }
+#endif
+    error(!BOOST_RESIZE_FILE(p.c_str(), size) ? BOOST_ERRNO : 0, p, ec, "boost::filesystem::resize_file");
+}
+
+BOOST_FILESYSTEM_DECL
+space_info space(path const& p, error_code* ec)
+{
+    space_info info;
+    // Initialize members to -1, as required by C++20 [fs.op.space]/1 in case of error
+    info.capacity = static_cast< uintmax_t >(-1);
+    info.free = static_cast< uintmax_t >(-1);
+    info.available = static_cast< uintmax_t >(-1);
+
+    if (ec)
+        ec->clear();
+
+#if defined(BOOST_FILESYSTEM_USE_WASI)
+
+    emit_error(BOOST_ERROR_NOT_SUPPORTED, p, ec, "boost::filesystem::space");
+
+#elif defined(BOOST_POSIX_API)
+
+    struct BOOST_STATVFS vfs;
+    if (!error(::BOOST_STATVFS(p.c_str(), &vfs) ? BOOST_ERRNO : 0, p, ec, "boost::filesystem::space"))
+    {
+        info.capacity = static_cast< uintmax_t >(vfs.f_blocks) * BOOST_STATVFS_F_FRSIZE;
+        info.free = static_cast< uintmax_t >(vfs.f_bfree) * BOOST_STATVFS_F_FRSIZE;
+        info.available = static_cast< uintmax_t >(vfs.f_bavail) * BOOST_STATVFS_F_FRSIZE;
+    }
+
+#else
+
+    // GetDiskFreeSpaceExW requires a directory path, which is unlike statvfs, which accepts any file.
+    // To work around this, test if the path refers to a directory and use the parent directory if not.
+    error_code local_ec;
+    file_status status = detail::status_impl(p, &local_ec);
+    if (status.type() == fs::status_error || status.type() == fs::file_not_found)
+    {
+    fail_local_ec:
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::space", p, local_ec));
+        *ec = local_ec;
+        return info;
+    }
+
+    path dir_path = p;
+    if (!is_directory(status))
+    {
+        path cur_path = detail::current_path(ec);
+        if (ec && *ec)
+            return info;
+
+        status = detail::symlink_status_impl(p, &local_ec);
+        if (status.type() == fs::status_error)
+            goto fail_local_ec;
+        if (is_symlink(status))
+        {
+            // We need to resolve the symlink so that we report the space for the symlink target
+            dir_path = detail::canonical_v4(p, cur_path, ec);
+            if (ec && *ec)
+                return info;
+        }
+
+        dir_path = dir_path.parent_path();
+        if (dir_path.empty())
+        {
+            // The original path was just a filename, which is a relative path wrt. current directory
+            dir_path = cur_path;
+        }
+    }
+
+    // For UNC names, the path must also include a trailing slash.
+    path::string_type str = dir_path.native();
+    if (str.size() >= 2u && detail::is_directory_separator(str[0]) && detail::is_directory_separator(str[1]) && !detail::is_directory_separator(*(str.end() - 1)))
+        str.push_back(path::preferred_separator);
+
+    ULARGE_INTEGER avail, total, free;
+    if (!error(::GetDiskFreeSpaceExW(str.c_str(), &avail, &total, &free) == 0 ? BOOST_ERRNO : 0, p, ec, "boost::filesystem::space"))
+    {
+        info.capacity = static_cast< uintmax_t >(total.QuadPart);
+        info.free = static_cast< uintmax_t >(free.QuadPart);
+        info.available = static_cast< uintmax_t >(avail.QuadPart);
+    }
+
+#endif
+
+    return info;
+}
+
+BOOST_FILESYSTEM_DECL
+file_status status(path const& p, error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+    return detail::status_impl(p, ec);
+}
+
+BOOST_FILESYSTEM_DECL
+file_status symlink_status(path const& p, error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+    return detail::symlink_status_impl(p, ec);
+}
+
+// contributed by Jeff Flinn
+BOOST_FILESYSTEM_DECL
+path temp_directory_path(system::error_code* ec)
+{
+    if (ec)
+        ec->clear();
+
+#ifdef BOOST_POSIX_API
+
+    const char* val = nullptr;
+
+    (val = std::getenv("TMPDIR")) ||
+        (val = std::getenv("TMP")) ||
+        (val = std::getenv("TEMP")) ||
+        (val = std::getenv("TEMPDIR"));
+
+#ifdef __ANDROID__
+    const char* default_tmp = "/data/local/tmp";
+#else
+    const char* default_tmp = "/tmp";
+#endif
+    path p((val != nullptr) ? val : default_tmp);
+
+    if (BOOST_UNLIKELY(p.empty()))
+    {
+    fail_not_dir:
+        error(ENOTDIR, p, ec, "boost::filesystem::temp_directory_path");
+        return p;
+    }
+
+    file_status status = detail::status_impl(p, ec);
+    if (BOOST_UNLIKELY(ec && *ec))
+        return path();
+    if (BOOST_UNLIKELY(!is_directory(status)))
+        goto fail_not_dir;
+
+    return p;
+
+#else // Windows
+
+    static const wchar_t* const env_list[] = { L"TMP", L"TEMP", L"LOCALAPPDATA", L"USERPROFILE" };
+    static const wchar_t temp_dir[] = L"Temp";
+
+    path p;
+    for (unsigned int i = 0; i < sizeof(env_list) / sizeof(*env_list); ++i)
+    {
+        std::wstring env = wgetenv(env_list[i]);
+        if (!env.empty())
+        {
+            p = env;
+            if (i >= 2)
+                path_algorithms::append_v4(p, temp_dir, temp_dir + (sizeof(temp_dir) / sizeof(*temp_dir) - 1u));
+            error_code lcl_ec;
+            if (exists(p, lcl_ec) && !lcl_ec && is_directory(p, lcl_ec) && !lcl_ec)
+                break;
+            p.clear();
+        }
+    }
+
+    if (p.empty())
+    {
+        // use a separate buffer since in C++03 a string is not required to be contiguous
+        const UINT size = ::GetWindowsDirectoryW(nullptr, 0);
+        if (BOOST_UNLIKELY(size == 0))
+        {
+        getwindir_error:
+            int errval = ::GetLastError();
+            error(errval, ec, "boost::filesystem::temp_directory_path");
+            return path();
+        }
+
+        std::unique_ptr< wchar_t[] > buf(new wchar_t[size]);
+        if (BOOST_UNLIKELY(::GetWindowsDirectoryW(buf.get(), size) == 0))
+            goto getwindir_error;
+
+        p = buf.get(); // do not depend on initial buf size, see ticket #10388
+        path_algorithms::append_v4(p, temp_dir, temp_dir + (sizeof(temp_dir) / sizeof(*temp_dir) - 1u));
+    }
+
+    return p;
+
+#endif
+}
+
+BOOST_FILESYSTEM_DECL
+path system_complete(path const& p, system::error_code* ec)
+{
+#ifdef BOOST_POSIX_API
+
+    if (p.empty() || p.is_absolute())
+        return p;
+
+    path res(current_path());
+    path_algorithms::append_v4(res, p);
+    return res;
+
+#else
+
+    if (p.empty())
+    {
+        if (ec)
+            ec->clear();
+        return p;
+    }
+
+    BOOST_CONSTEXPR_OR_CONST std::size_t buf_size = 128u;
+    wchar_t buf[buf_size];
+    wchar_t* pfn;
+    std::size_t len = get_full_path_name(p, buf_size, buf, &pfn);
+
+    if (error(len == 0 ? BOOST_ERRNO : 0, p, ec, "boost::filesystem::system_complete"))
+        return path();
+
+    if (len < buf_size) // len does not include null termination character
+        return path(&buf[0]);
+
+    std::unique_ptr< wchar_t[] > big_buf(new wchar_t[len]);
+
+    return error(get_full_path_name(p, len, big_buf.get(), &pfn) == 0 ? BOOST_ERRNO : 0, p, ec, "boost::filesystem::system_complete") ? path() : path(big_buf.get());
+
+#endif
+}
+
+BOOST_FILESYSTEM_DECL
+path weakly_canonical_v3(path const& p, path const& base, system::error_code* ec)
+{
+    path source(detail::absolute_v3(p, base, ec));
+    if (ec && *ec)
+    {
+    return_empty_path:
+        return path();
+    }
+
+    system::error_code local_ec;
+    const path::iterator source_end(source.end());
+
+#if defined(BOOST_POSIX_API)
+
+    path::iterator itr(source_end);
+    path head(source);
+    for (; !head.empty(); path_algorithms::decrement_v4(itr))
+    {
+        file_status head_status(detail::status_impl(head, &local_ec));
+        if (BOOST_UNLIKELY(head_status.type() == fs::status_error))
+        {
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::weakly_canonical", head, local_ec));
+
+            *ec = local_ec;
+            goto return_empty_path;
+        }
+
+        if (head_status.type() != fs::file_not_found)
+            break;
+
+        head.remove_filename_and_trailing_separators();
+    }
+
+    path const& dot_p = dot_path();
+    path const& dot_dot_p = dot_dot_path();
+
+#else
+
+    path const& dot_p = dot_path();
+    path const& dot_dot_p = dot_dot_path();
+
+    // On Windows, filesystem APIs such as GetFileAttributesW and CreateFileW perform lexical path normalization
+    // internally. As a result, a path like "c:\a\.." can be reported as present even if "c:\a" is not. This would
+    // break canonical, as symlink_status that it calls internally would report an error that the file at the
+    // intermediate path does not exist. To avoid this, scan the initial path in the forward direction.
+    // Also, operate on paths with preferred separators. This can be important on Windows since GetFileAttributesW
+    // or CreateFileW, which is called in status() may return "file not found" for paths to network shares and
+    // mounted cloud storages that have forward slashes as separators.
+    // Also, avoid querying status of the root name such as \\?\c: as CreateFileW returns ERROR_INVALID_FUNCTION for
+    // such path. Querying the status of a root name such as c: is also not right as this path refers to the current
+    // directory on drive C:, which is not what we want to test for existence anyway.
+    path::iterator itr(source.begin());
+    path head;
+    if (source.has_root_name())
+    {
+        BOOST_ASSERT(itr != source_end);
+        head = *itr;
+        path_algorithms::increment_v4(itr);
+    }
+
+    if (source.has_root_directory())
+    {
+        BOOST_ASSERT(itr != source_end);
+        // Convert generic separator returned by the iterator for the root directory to
+        // the preferred separator.
+        head += path::preferred_separator;
+        path_algorithms::increment_v4(itr);
+    }
+
+    if (!head.empty())
+    {
+        file_status head_status(detail::status_impl(head, &local_ec));
+        if (BOOST_UNLIKELY(head_status.type() == fs::status_error))
+        {
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::weakly_canonical", head, local_ec));
+
+            *ec = local_ec;
+            goto return_empty_path;
+        }
+
+        if (head_status.type() == fs::file_not_found)
+        {
+            // If the root path does not exist then no path element exists
+            itr = source.begin();
+            head.clear();
+            goto skip_head;
+        }
+    }
+
+    for (; itr != source_end; path_algorithms::increment_v4(itr))
+    {
+        path const& source_elem = *itr;
+
+        // Avoid querying status of paths containing dot and dot-dot elements, as this will break
+        // if the root name starts with "\\?\".
+        if (path_algorithms::compare_v4(source_elem, dot_p) == 0)
+            continue;
+
+        if (path_algorithms::compare_v4(source_elem, dot_dot_p) == 0)
+        {
+            if (head.has_relative_path())
+                head.remove_filename_and_trailing_separators();
+
+            continue;
+        }
+
+        path_algorithms::append_v4(head, source_elem);
+
+        file_status head_status(detail::status_impl(head, &local_ec));
+        if (BOOST_UNLIKELY(head_status.type() == fs::status_error))
+        {
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::weakly_canonical", head, local_ec));
+
+            *ec = local_ec;
+            goto return_empty_path;
+        }
+
+        if (head_status.type() == fs::file_not_found)
+        {
+            head.remove_filename_and_trailing_separators();
+            break;
+        }
+    }
+
+skip_head:;
+
+#endif
+
+    path tail;
+    bool tail_has_dots = false;
+    for (; itr != source_end; path_algorithms::increment_v4(itr))
+    {
+        path const& tail_elem = *itr;
+        path_algorithms::append_v4(tail, tail_elem);
+        // for a later optimization, track if any dot or dot-dot elements are present
+        if (!tail_has_dots && (path_algorithms::compare_v4(tail_elem, dot_p) == 0 || path_algorithms::compare_v4(tail_elem, dot_dot_p) == 0))
+            tail_has_dots = true;
+    }
+
+    head = detail::canonical_v3(head, base, &local_ec);
+    if (BOOST_UNLIKELY(!!local_ec))
+    {
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::weakly_canonical", head, local_ec));
+
+        *ec = local_ec;
+        goto return_empty_path;
+    }
+
+    if (BOOST_LIKELY(!tail.empty()))
+    {
+        path_algorithms::append_v4(head, tail);
+
+        // optimization: only normalize if tail had dot or dot-dot element
+        if (tail_has_dots)
+            head = path_algorithms::lexically_normal_v4(head);
+    }
+
+    return head;
+}
+
+BOOST_FILESYSTEM_DECL
+path weakly_canonical_v4(path const& p, path const& base, system::error_code* ec)
+{
+    path source(detail::absolute_v4(p, base, ec));
+    if (ec && *ec)
+    {
+    return_empty_path:
+        return path();
+    }
+
+    system::error_code local_ec;
+    const path::iterator source_end(source.end());
+
+#if defined(BOOST_POSIX_API)
+
+    path::iterator itr(source_end);
+    path head(source);
+    for (; !head.empty(); path_algorithms::decrement_v4(itr))
+    {
+        file_status head_status(detail::status_impl(head, &local_ec));
+        if (BOOST_UNLIKELY(head_status.type() == fs::status_error))
+        {
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::weakly_canonical", head, local_ec));
+
+            *ec = local_ec;
+            goto return_empty_path;
+        }
+
+        if (head_status.type() != fs::file_not_found)
+            break;
+
+        head.remove_filename_and_trailing_separators();
+    }
+
+    path const& dot_p = dot_path();
+    path const& dot_dot_p = dot_dot_path();
+
+#else
+
+    path const& dot_p = dot_path();
+    path const& dot_dot_p = dot_dot_path();
+
+    // On Windows, filesystem APIs such as GetFileAttributesW and CreateFileW perform lexical path normalization
+    // internally. As a result, a path like "c:\a\.." can be reported as present even if "c:\a" is not. This would
+    // break canonical, as symlink_status that it calls internally would report an error that the file at the
+    // intermediate path does not exist. To avoid this, scan the initial path in the forward direction.
+    // Also, operate on paths with preferred separators. This can be important on Windows since GetFileAttributesW
+    // or CreateFileW, which is called in status() may return "file not found" for paths to network shares and
+    // mounted cloud storages that have forward slashes as separators.
+    // Also, avoid querying status of the root name such as \\?\c: as CreateFileW returns ERROR_INVALID_FUNCTION for
+    // such path. Querying the status of a root name such as c: is also not right as this path refers to the current
+    // directory on drive C:, which is not what we want to test for existence anyway.
+    path::iterator itr(source.begin());
+    path head;
+    if (source.has_root_name())
+    {
+        BOOST_ASSERT(itr != source_end);
+        head = *itr;
+        path_algorithms::increment_v4(itr);
+    }
+
+    if (source.has_root_directory())
+    {
+        BOOST_ASSERT(itr != source_end);
+        // Convert generic separator returned by the iterator for the root directory to
+        // the preferred separator.
+        head += path::preferred_separator;
+        path_algorithms::increment_v4(itr);
+    }
+
+    if (!head.empty())
+    {
+        file_status head_status(detail::status_impl(head, &local_ec));
+        if (BOOST_UNLIKELY(head_status.type() == fs::status_error))
+        {
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::weakly_canonical", head, local_ec));
+
+            *ec = local_ec;
+            goto return_empty_path;
+        }
+
+        if (head_status.type() == fs::file_not_found)
+        {
+            // If the root path does not exist then no path element exists
+            itr = source.begin();
+            head.clear();
+            goto skip_head;
+        }
+    }
+
+    for (; itr != source_end; path_algorithms::increment_v4(itr))
+    {
+        path const& source_elem = *itr;
+
+        // Avoid querying status of paths containing dot and dot-dot elements, as this will break
+        // if the root name starts with "\\?\".
+        if (path_algorithms::compare_v4(source_elem, dot_p) == 0)
+            continue;
+
+        if (path_algorithms::compare_v4(source_elem, dot_dot_p) == 0)
+        {
+            if (head.has_relative_path())
+                head.remove_filename_and_trailing_separators();
+
+            continue;
+        }
+
+        path_algorithms::append_v4(head, source_elem);
+
+        file_status head_status(detail::status_impl(head, &local_ec));
+        if (BOOST_UNLIKELY(head_status.type() == fs::status_error))
+        {
+            if (!ec)
+                BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::weakly_canonical", head, local_ec));
+
+            *ec = local_ec;
+            goto return_empty_path;
+        }
+
+        if (head_status.type() == fs::file_not_found)
+        {
+            head.remove_filename_and_trailing_separators();
+            break;
+        }
+    }
+
+skip_head:;
+
+#endif
+
+    path tail;
+    bool tail_has_dots = false;
+    for (; itr != source_end; path_algorithms::increment_v4(itr))
+    {
+        path const& tail_elem = *itr;
+        path_algorithms::append_v4(tail, tail_elem);
+        // for a later optimization, track if any dot or dot-dot elements are present
+        if (!tail_has_dots && (path_algorithms::compare_v4(tail_elem, dot_p) == 0 || path_algorithms::compare_v4(tail_elem, dot_dot_p) == 0))
+            tail_has_dots = true;
+    }
+
+    head = detail::canonical_v4(head, base, &local_ec);
+    if (BOOST_UNLIKELY(!!local_ec))
+    {
+        if (!ec)
+            BOOST_FILESYSTEM_THROW(filesystem_error("boost::filesystem::weakly_canonical", head, local_ec));
+
+        *ec = local_ec;
+        goto return_empty_path;
+    }
+
+    if (BOOST_LIKELY(!tail.empty()))
+    {
+        path_algorithms::append_v4(head, tail);
+
+        // optimization: only normalize if tail had dot or dot-dot element
+        if (tail_has_dots)
+            head = path_algorithms::lexically_normal_v4(head);
+    }
+
+    return head;
+}
+
+} // namespace detail
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
diff --git a/contrib/restricted/boost/filesystem/src/path.cpp b/contrib/restricted/boost/filesystem/src/path.cpp
new file mode 100644
index 0000000000..82b2c7d520
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/path.cpp
@@ -0,0 +1,1719 @@
+//  filesystem path.cpp  -------------------------------------------------------------  //
+
+//  Copyright Beman Dawes 2008
+//  Copyright Andrey Semashev 2021-2024
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  Library home page: http://www.boost.org/libs/filesystem
+
+#include "platform_config.hpp"
+
+#include <boost/filesystem/config.hpp>
+#include <boost/filesystem/path.hpp>
+#include <boost/filesystem/detail/path_traits.hpp> // codecvt_error_category()
+#include <boost/system/error_category.hpp> // for BOOST_SYSTEM_HAS_CONSTEXPR
+#include <boost/assert.hpp>
+#include <algorithm>
+#include <iterator>
+#include <utility>
+#include <string>
+#include <cstddef>
+#include <cstring>
+#include <cstdlib> // std::atexit
+
+#ifdef BOOST_WINDOWS_API
+#include "windows_file_codecvt.hpp"
+#include "windows_tools.hpp"
+#include <windows.h>
+#elif defined(macintosh) || defined(__APPLE__) || defined(__APPLE_CC__) || defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__HAIKU__)
+#include <boost/filesystem/detail/utf8_codecvt_facet.hpp>
+#endif
+
+#ifdef BOOST_FILESYSTEM_DEBUG
+#include <iostream>
+#include <iomanip>
+#endif
+
+#include "atomic_tools.hpp"
+#include "private_config.hpp"
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+namespace fs = boost::filesystem;
+
+using boost::filesystem::path;
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//                                class path helpers                                    //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+namespace {
+//------------------------------------------------------------------------------------//
+//                        miscellaneous class path helpers                            //
+//------------------------------------------------------------------------------------//
+
+typedef path::value_type value_type;
+typedef path::string_type string_type;
+typedef string_type::size_type size_type;
+
+#ifdef BOOST_WINDOWS_API
+
+const wchar_t dot_path_literal[] = L".";
+const wchar_t dot_dot_path_literal[] = L"..";
+const wchar_t separators[] = L"/\\";
+using boost::filesystem::detail::colon;
+using boost::filesystem::detail::questionmark;
+
+inline bool is_alnum(wchar_t c)
+{
+    return boost::filesystem::detail::is_letter(c) || (c >= L'0' && c <= L'9');
+}
+
+inline bool is_device_name_char(wchar_t c)
+{
+    // https://googleprojectzero.blogspot.com/2016/02/the-definitive-guide-on-win32-to-nt.html
+    // Device names are:
+    //
+    // - PRN
+    // - AUX
+    // - NUL
+    // - CON
+    // - LPT[1-9]
+    // - COM[1-9]
+    // - CONIN$
+    // - CONOUT$
+    return is_alnum(c) || c == L'$';
+}
+
+//! Returns position of the first directory separator in the \a size initial characters of \a p, or \a size if not found
+inline size_type find_separator(const wchar_t* p, size_type size) noexcept
+{
+    size_type pos = 0u;
+    for (; pos < size; ++pos)
+    {
+        const wchar_t c = p[pos];
+        if (boost::filesystem::detail::is_directory_separator(c))
+            break;
+    }
+    return pos;
+}
+
+#else // BOOST_WINDOWS_API
+
+const char dot_path_literal[] = ".";
+const char dot_dot_path_literal[] = "..";
+const char separators[] = "/";
+
+//! Returns position of the first directory separator in the \a size initial characters of \a p, or \a size if not found
+inline size_type find_separator(const char* p, size_type size) noexcept
+{
+    const char* sep = static_cast< const char* >(std::memchr(p, '/', size));
+    size_type pos = size;
+    if (BOOST_LIKELY(!!sep))
+        pos = sep - p;
+    return pos;
+}
+
+#endif // BOOST_WINDOWS_API
+
+// pos is position of the separator
+bool is_root_separator(string_type const& str, size_type root_dir_pos, size_type pos);
+
+// Returns: Size of the filename element that ends at end_pos (which is past-the-end position). 0 if no filename found.
+size_type find_filename_size(string_type const& str, size_type root_name_size, size_type end_pos);
+
+// Returns: starting position of root directory or size if not found. Sets root_name_size to length
+// of the root name if the characters before the returned position (if any) are considered a root name.
+size_type find_root_directory_start(const value_type* path, size_type size, size_type& root_name_size);
+
+// Finds position and size of the first element of the path
+void first_element(string_type const& src, size_type& element_pos, size_type& element_size, size_type size);
+
+// Finds position and size of the first element of the path
+inline void first_element(string_type const& src, size_type& element_pos, size_type& element_size)
+{
+    first_element(src, element_pos, element_size, src.size());
+}
+
+} // unnamed namespace
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//                            class path implementation                                 //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+namespace boost {
+namespace filesystem {
+namespace detail {
+
+// C++14 provides a mismatch algorithm with four iterator arguments(), but earlier
+// standard libraries didn't, so provide this needed functionality.
+inline std::pair< path::iterator, path::iterator > mismatch(path::iterator it1, path::iterator it1end, path::iterator it2, path::iterator it2end)
+{
+    for (; it1 != it1end && it2 != it2end && path_algorithms::compare_v4(*it1, *it2) == 0;)
+    {
+        path_algorithms::increment_v4(it1);
+        path_algorithms::increment_v4(it2);
+    }
+    return std::make_pair(it1, it2);
+}
+
+//  normal  --------------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL path path_algorithms::lexically_normal_v3(path const& p)
+{
+    const value_type* const pathname = p.m_pathname.c_str();
+    const size_type pathname_size = p.m_pathname.size();
+    size_type root_name_size = 0;
+    size_type root_dir_pos = find_root_directory_start(pathname, pathname_size, root_name_size);
+    path normal(pathname, pathname + root_name_size);
+
+#if defined(BOOST_WINDOWS_API)
+    for (size_type i = 0; i < root_name_size; ++i)
+    {
+        if (normal.m_pathname[i] == path::separator)
+            normal.m_pathname[i] = path::preferred_separator;
+    }
+#endif
+
+    size_type root_path_size = root_name_size;
+    if (root_dir_pos < pathname_size)
+    {
+        root_path_size = root_dir_pos + 1;
+        normal.m_pathname.push_back(path::preferred_separator);
+    }
+
+    size_type i = root_path_size;
+
+    // Skip redundant directory separators after the root directory
+    while (i < pathname_size && detail::is_directory_separator(pathname[i]))
+        ++i;
+
+    if (i < pathname_size)
+    {
+        bool last_element_was_dot = false;
+        while (true)
+        {
+            {
+                const size_type start_pos = i;
+
+                // Find next separator
+                i += find_separator(pathname + i, pathname_size - i);
+
+                const size_type size = i - start_pos;
+
+                // Skip dot elements
+                if (size == 1u && pathname[start_pos] == path::dot)
+                {
+                    last_element_was_dot = true;
+                    goto skip_append;
+                }
+
+                last_element_was_dot = false;
+
+                // Process dot dot elements
+                if (size == 2u && pathname[start_pos] == path::dot && pathname[start_pos + 1] == path::dot && normal.m_pathname.size() > root_path_size)
+                {
+                    // Don't remove previous dot dot elements
+                    const size_type normal_size = normal.m_pathname.size();
+                    size_type filename_size = find_filename_size(normal.m_pathname, root_path_size, normal_size);
+                    size_type pos = normal_size - filename_size;
+                    if (filename_size != 2u || normal.m_pathname[pos] != path::dot || normal.m_pathname[pos + 1] != path::dot)
+                    {
+                        if (pos > root_path_size && detail::is_directory_separator(normal.m_pathname[pos - 1]))
+                            --pos;
+                        normal.m_pathname.erase(normal.m_pathname.begin() + pos , normal.m_pathname.end());
+                        goto skip_append;
+                    }
+                }
+
+                // Append the element
+                path_algorithms::append_separator_if_needed(normal);
+                normal.m_pathname.append(pathname + start_pos, size);
+            }
+
+        skip_append:
+            if (i == pathname_size)
+                break;
+
+            // Skip directory separators, including duplicates
+            while (i < pathname_size && detail::is_directory_separator(pathname[i]))
+                ++i;
+
+            if (i == pathname_size)
+            {
+                // If a path ends with a separator, add a trailing dot element
+                goto append_trailing_dot;
+            }
+        }
+
+        if (normal.empty() || last_element_was_dot)
+        {
+        append_trailing_dot:
+            path_algorithms::append_separator_if_needed(normal);
+            normal.m_pathname.push_back(path::dot);
+        }
+    }
+
+    return normal;
+}
+
+BOOST_FILESYSTEM_DECL path path_algorithms::lexically_normal_v4(path const& p)
+{
+    const value_type* const pathname = p.m_pathname.c_str();
+    const size_type pathname_size = p.m_pathname.size();
+    size_type root_name_size = 0;
+    size_type root_dir_pos = find_root_directory_start(pathname, pathname_size, root_name_size);
+    path normal(pathname, pathname + root_name_size);
+
+    size_type root_path_size = root_name_size;
+    if (root_dir_pos < pathname_size)
+    {
+        root_path_size = root_dir_pos + 1;
+        normal.m_pathname.push_back(path::preferred_separator);
+    }
+
+    size_type i = root_path_size;
+
+    // Skip redundant directory separators after the root directory
+    while (i < pathname_size && detail::is_directory_separator(pathname[i]))
+        ++i;
+
+    if (i < pathname_size)
+    {
+        while (true)
+        {
+            bool last_element_was_dot = false;
+            {
+                const size_type start_pos = i;
+
+                // Find next separator
+                i += find_separator(pathname + i, pathname_size - i);
+
+                const size_type size = i - start_pos;
+
+                // Skip dot elements
+                if (size == 1u && pathname[start_pos] == path::dot)
+                {
+                    last_element_was_dot = true;
+                    goto skip_append;
+                }
+
+                // Process dot dot elements
+                if (size == 2u && pathname[start_pos] == path::dot && pathname[start_pos + 1] == path::dot && normal.m_pathname.size() > root_path_size)
+                {
+                    // Don't remove previous dot dot elements
+                    const size_type normal_size = normal.m_pathname.size();
+                    size_type filename_size = find_filename_size(normal.m_pathname, root_path_size, normal_size);
+                    size_type pos = normal_size - filename_size;
+                    if (filename_size != 2u || normal.m_pathname[pos] != path::dot || normal.m_pathname[pos + 1] != path::dot)
+                    {
+                        if (pos > root_path_size && detail::is_directory_separator(normal.m_pathname[pos - 1]))
+                            --pos;
+                        normal.m_pathname.erase(normal.m_pathname.begin() + pos, normal.m_pathname.end());
+                        goto skip_append;
+                    }
+                }
+
+                // Append the element
+                path_algorithms::append_separator_if_needed(normal);
+                normal.m_pathname.append(pathname + start_pos, size);
+            }
+
+        skip_append:
+            if (i == pathname_size)
+            {
+                // If a path ends with a trailing dot after a directory element, add a trailing separator
+                if (last_element_was_dot && !normal.empty() && !normal.filename_is_dot_dot())
+                    path_algorithms::append_separator_if_needed(normal);
+
+                break;
+            }
+
+            // Skip directory separators, including duplicates
+            while (i < pathname_size && detail::is_directory_separator(pathname[i]))
+                ++i;
+
+            if (i == pathname_size)
+            {
+                // If a path ends with a separator, add a trailing separator
+                if (!normal.empty() && !normal.filename_is_dot_dot())
+                    path_algorithms::append_separator_if_needed(normal);
+                break;
+            }
+        }
+
+        // If the original path was not empty and normalized ended up being empty, make it a dot
+        if (normal.empty())
+            normal.m_pathname.push_back(path::dot);
+    }
+
+    return normal;
+}
+
+//  generic_path ---------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL path path_algorithms::generic_path_v3(path const& p)
+{
+    path tmp;
+    const size_type pathname_size = p.m_pathname.size();
+    tmp.m_pathname.reserve(pathname_size);
+
+    const value_type* const pathname = p.m_pathname.c_str();
+
+    // Don't remove duplicate slashes from the root name
+    size_type root_name_size = 0u;
+    size_type root_dir_pos = find_root_directory_start(pathname, pathname_size, root_name_size);
+    if (root_name_size > 0u)
+    {
+        tmp.m_pathname.append(pathname, root_name_size);
+#if defined(BOOST_WINDOWS_API)
+        std::replace(tmp.m_pathname.begin(), tmp.m_pathname.end(), L'\\', L'/');
+#endif
+    }
+
+    size_type pos = root_name_size;
+    if (root_dir_pos < pathname_size)
+    {
+        tmp.m_pathname.push_back(path::separator);
+        pos = root_dir_pos + 1u;
+    }
+
+    while (pos < pathname_size)
+    {
+        size_type element_size = find_separator(pathname + pos, pathname_size - pos);
+        if (element_size > 0u)
+        {
+            tmp.m_pathname.append(pathname + pos, element_size);
+
+            pos += element_size;
+            if (pos >= pathname_size)
+                break;
+
+            tmp.m_pathname.push_back(path::separator);
+        }
+
+        ++pos;
+    }
+
+    return tmp;
+}
+
+BOOST_FILESYSTEM_DECL path path_algorithms::generic_path_v4(path const& p)
+{
+    path tmp;
+    const size_type pathname_size = p.m_pathname.size();
+    tmp.m_pathname.reserve(pathname_size);
+
+    const value_type* const pathname = p.m_pathname.c_str();
+
+    // Treat root name specially as it may contain backslashes, duplicate ones too,
+    // in case of UNC paths and Windows-specific prefixes.
+    size_type root_name_size = 0u;
+    size_type root_dir_pos = find_root_directory_start(pathname, pathname_size, root_name_size);
+    if (root_name_size > 0u)
+        tmp.m_pathname.append(pathname, root_name_size);
+
+    size_type pos = root_name_size;
+    if (root_dir_pos < pathname_size)
+    {
+        tmp.m_pathname.push_back(path::separator);
+        pos = root_dir_pos + 1u;
+    }
+
+    while (pos < pathname_size)
+    {
+        size_type element_size = find_separator(pathname + pos, pathname_size - pos);
+        if (element_size > 0u)
+        {
+            tmp.m_pathname.append(pathname + pos, element_size);
+
+            pos += element_size;
+            if (pos >= pathname_size)
+                break;
+
+            tmp.m_pathname.push_back(path::separator);
+        }
+
+        ++pos;
+    }
+
+    return tmp;
+}
+
+#if defined(BOOST_WINDOWS_API)
+
+//  make_preferred -------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL void path_algorithms::make_preferred_v3(path& p)
+{
+    std::replace(p.m_pathname.begin(), p.m_pathname.end(), L'/', L'\\');
+}
+
+BOOST_FILESYSTEM_DECL void path_algorithms::make_preferred_v4(path& p)
+{
+    const size_type pathname_size = p.m_pathname.size();
+    if (pathname_size > 0u)
+    {
+        value_type* const pathname = &p.m_pathname[0];
+
+        // Avoid converting slashes in the root name
+        size_type root_name_size = 0u;
+        find_root_directory_start(pathname, pathname_size, root_name_size);
+
+        std::replace(pathname + root_name_size, pathname + pathname_size, L'/', L'\\');
+    }
+}
+
+#endif // defined(BOOST_WINDOWS_API)
+
+//  append  --------------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL void path_algorithms::append_v3(path& p, const value_type* begin, const value_type* end)
+{
+    if (begin != end)
+    {
+        if (BOOST_LIKELY(begin < p.m_pathname.data() || begin >= (p.m_pathname.data() + p.m_pathname.size())))
+        {
+            if (!detail::is_directory_separator(*begin))
+                path_algorithms::append_separator_if_needed(p);
+            p.m_pathname.append(begin, end);
+        }
+        else
+        {
+            // overlapping source
+            string_type rhs(begin, end);
+            path_algorithms::append_v3(p, rhs.data(), rhs.data() + rhs.size());
+        }
+    }
+}
+
+BOOST_FILESYSTEM_DECL void path_algorithms::append_v4(path& p, const value_type* begin, const value_type* end)
+{
+    if (begin != end)
+    {
+        if (BOOST_LIKELY(begin < p.m_pathname.data() || begin >= (p.m_pathname.data() + p.m_pathname.size())))
+        {
+            const size_type that_size = end - begin;
+            size_type that_root_name_size = 0;
+            size_type that_root_dir_pos = find_root_directory_start(begin, that_size, that_root_name_size);
+
+            // if (p.is_absolute())
+            if
+            (
+#if defined(BOOST_WINDOWS_API)
+                that_root_name_size > 0 &&
+#endif
+                that_root_dir_pos < that_size
+            )
+            {
+            return_assign:
+                p.assign(begin, end);
+                return;
+            }
+
+            size_type this_root_name_size = 0;
+            find_root_directory_start(p.m_pathname.c_str(), p.m_pathname.size(), this_root_name_size);
+
+            if
+            (
+                that_root_name_size > 0 &&
+                (that_root_name_size != this_root_name_size || std::memcmp(p.m_pathname.c_str(), begin, this_root_name_size * sizeof(value_type)) != 0)
+            )
+            {
+                goto return_assign;
+            }
+
+            if (that_root_dir_pos < that_size)
+            {
+                // Remove root directory (if any) and relative path to replace with those from p
+                p.m_pathname.erase(p.m_pathname.begin() + this_root_name_size, p.m_pathname.end());
+            }
+
+            const value_type* const that_path = begin + that_root_name_size;
+            if (!detail::is_directory_separator(*that_path))
+                path_algorithms::append_separator_if_needed(p);
+            p.m_pathname.append(that_path, end);
+        }
+        else
+        {
+            // overlapping source
+            string_type rhs(begin, end);
+            path_algorithms::append_v4(p, rhs.data(), rhs.data() + rhs.size());
+        }
+    }
+    else if (path_algorithms::has_filename_v4(p))
+    {
+        p.m_pathname.push_back(path::preferred_separator);
+    }
+}
+
+//  compare  -------------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL int path_algorithms::lex_compare_v3
+(
+    path_detail::path_iterator first1, path_detail::path_iterator const& last1,
+    path_detail::path_iterator first2, path_detail::path_iterator const& last2
+)
+{
+    for (; first1 != last1 && first2 != last2;)
+    {
+        if (first1->native() < first2->native())
+            return -1;
+        if (first2->native() < first1->native())
+            return 1;
+        BOOST_ASSERT(first2->native() == first1->native());
+        path_algorithms::increment_v3(first1);
+        path_algorithms::increment_v3(first2);
+    }
+    if (first1 == last1 && first2 == last2)
+        return 0;
+    return first1 == last1 ? -1 : 1;
+}
+
+BOOST_FILESYSTEM_DECL int path_algorithms::lex_compare_v4
+(
+    path_detail::path_iterator first1, path_detail::path_iterator const& last1,
+    path_detail::path_iterator first2, path_detail::path_iterator const& last2
+)
+{
+    for (; first1 != last1 && first2 != last2;)
+    {
+        if (first1->native() < first2->native())
+            return -1;
+        if (first2->native() < first1->native())
+            return 1;
+        BOOST_ASSERT(first2->native() == first1->native());
+        path_algorithms::increment_v4(first1);
+        path_algorithms::increment_v4(first2);
+    }
+    if (first1 == last1 && first2 == last2)
+        return 0;
+    return first1 == last1 ? -1 : 1;
+}
+
+BOOST_FILESYSTEM_DECL int path_algorithms::compare_v3(path const& left, path const& right)
+{
+    return path_algorithms::lex_compare_v3(left.begin(), left.end(), right.begin(), right.end());
+}
+
+BOOST_FILESYSTEM_DECL int path_algorithms::compare_v4(path const& left, path const& right)
+{
+    return path_algorithms::lex_compare_v4(left.begin(), left.end(), right.begin(), right.end());
+}
+
+//  append_separator_if_needed  ------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL path_algorithms::string_type::size_type path_algorithms::append_separator_if_needed(path& p)
+{
+    if (!p.m_pathname.empty() &&
+#ifdef BOOST_WINDOWS_API
+        *(p.m_pathname.end() - 1) != colon &&
+#endif
+        !detail::is_directory_separator(*(p.m_pathname.end() - 1)))
+    {
+        string_type::size_type tmp(p.m_pathname.size());
+        p.m_pathname.push_back(path::preferred_separator);
+        return tmp;
+    }
+    return 0;
+}
+
+//  erase_redundant_separator  -------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL void path_algorithms::erase_redundant_separator(path& p, string_type::size_type sep_pos)
+{
+    if (sep_pos                                          // a separator was added
+        && sep_pos < p.m_pathname.size()                 // and something was appended
+        && (p.m_pathname[sep_pos + 1] == path::separator // and it was also separator
+#ifdef BOOST_WINDOWS_API
+            || p.m_pathname[sep_pos + 1] == path::preferred_separator // or preferred_separator
+#endif
+            ))
+    {
+        p.m_pathname.erase(p.m_pathname.begin() + sep_pos); // erase the added separator
+    }
+}
+
+//  modifiers  -----------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL void path_algorithms::remove_filename_v3(path& p)
+{
+    p.remove_filename_and_trailing_separators();
+}
+
+BOOST_FILESYSTEM_DECL void path_algorithms::remove_filename_v4(path& p)
+{
+    size_type filename_size = path_algorithms::find_filename_v4_size(p);
+    p.m_pathname.erase(p.m_pathname.begin() + (p.m_pathname.size() - filename_size), p.m_pathname.end());
+}
+
+BOOST_FILESYSTEM_DECL void path_algorithms::replace_extension_v3(path& p, path const& new_extension)
+{
+    // erase existing extension, including the dot, if any
+    size_type ext_pos = p.m_pathname.size() - path_algorithms::extension_v3(p).m_pathname.size();
+    p.m_pathname.erase(p.m_pathname.begin() + ext_pos, p.m_pathname.end());
+
+    if (!new_extension.empty())
+    {
+        // append new_extension, adding the dot if necessary
+        if (new_extension.m_pathname[0] != path::dot)
+            p.m_pathname.push_back(path::dot);
+        p.m_pathname.append(new_extension.m_pathname);
+    }
+}
+
+BOOST_FILESYSTEM_DECL void path_algorithms::replace_extension_v4(path& p, path const& new_extension)
+{
+    // erase existing extension, including the dot, if any
+    size_type ext_pos = p.m_pathname.size() - path_algorithms::find_extension_v4_size(p);
+    p.m_pathname.erase(p.m_pathname.begin() + ext_pos, p.m_pathname.end());
+
+    if (!new_extension.empty())
+    {
+        // append new_extension, adding the dot if necessary
+        if (new_extension.m_pathname[0] != path::dot)
+            p.m_pathname.push_back(path::dot);
+        p.m_pathname.append(new_extension.m_pathname);
+    }
+}
+
+//  decomposition  -------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL size_type path_algorithms::find_root_name_size(path const& p)
+{
+    size_type root_name_size = 0;
+    find_root_directory_start(p.m_pathname.c_str(), p.m_pathname.size(), root_name_size);
+    return root_name_size;
+}
+
+BOOST_FILESYSTEM_DECL size_type path_algorithms::find_root_path_size(path const& p)
+{
+    size_type root_name_size = 0;
+    size_type root_dir_pos = find_root_directory_start(p.m_pathname.c_str(), p.m_pathname.size(), root_name_size);
+
+    size_type size = root_name_size;
+    if (root_dir_pos < p.m_pathname.size())
+        size = root_dir_pos + 1;
+
+    return size;
+}
+
+BOOST_FILESYSTEM_DECL path_algorithms::substring path_algorithms::find_root_directory(path const& p)
+{
+    substring root_dir;
+    size_type root_name_size = 0;
+    root_dir.pos = find_root_directory_start(p.m_pathname.c_str(), p.m_pathname.size(), root_name_size);
+    root_dir.size = static_cast< std::size_t >(root_dir.pos < p.m_pathname.size());
+    return root_dir;
+}
+
+BOOST_FILESYSTEM_DECL path_algorithms::substring path_algorithms::find_relative_path(path const& p)
+{
+    size_type root_name_size = 0;
+    size_type root_dir_pos = find_root_directory_start(p.m_pathname.c_str(), p.m_pathname.size(), root_name_size);
+
+    // Skip root name, root directory and any duplicate separators
+    size_type size = root_name_size;
+    if (root_dir_pos < p.m_pathname.size())
+    {
+        size = root_dir_pos + 1;
+
+        for (size_type n = p.m_pathname.size(); size < n; ++size)
+        {
+            if (!detail::is_directory_separator(p.m_pathname[size]))
+                break;
+        }
+    }
+
+    substring rel_path;
+    rel_path.pos = size;
+    rel_path.size = p.m_pathname.size() - size;
+
+    return rel_path;
+}
+
+BOOST_FILESYSTEM_DECL path_algorithms::string_type::size_type path_algorithms::find_parent_path_size(path const& p)
+{
+    const size_type size = p.m_pathname.size();
+    size_type root_name_size = 0;
+    size_type root_dir_pos = find_root_directory_start(p.m_pathname.c_str(), size, root_name_size);
+
+    size_type filename_size = find_filename_size(p.m_pathname, root_name_size, size);
+    size_type end_pos = size - filename_size;
+    while (true)
+    {
+        if (end_pos <= root_name_size)
+        {
+            // Keep the root name as the parent path if there was a filename
+            if (filename_size == 0)
+                end_pos = 0u;
+            break;
+        }
+
+        --end_pos;
+
+        if (!detail::is_directory_separator(p.m_pathname[end_pos]))
+        {
+            ++end_pos;
+            break;
+        }
+
+        if (end_pos == root_dir_pos)
+        {
+            // Keep the trailing root directory if there was a filename
+            end_pos += filename_size > 0;
+            break;
+        }
+    }
+
+    return end_pos;
+}
+
+BOOST_FILESYSTEM_DECL path path_algorithms::filename_v3(path const& p)
+{
+    const size_type size = p.m_pathname.size();
+    size_type root_name_size = 0;
+    size_type root_dir_pos = find_root_directory_start(p.m_pathname.c_str(), size, root_name_size);
+    size_type filename_size, pos;
+    if (root_dir_pos < size && detail::is_directory_separator(p.m_pathname[size - 1]) && is_root_separator(p.m_pathname, root_dir_pos, size - 1))
+    {
+        // Return root directory
+        pos = root_dir_pos;
+        filename_size = 1u;
+    }
+    else if (root_name_size == size)
+    {
+        // Return root name
+        pos = 0u;
+        filename_size = root_name_size;
+    }
+    else
+    {
+        filename_size = find_filename_size(p.m_pathname, root_name_size, size);
+        pos = size - filename_size;
+        if (filename_size == 0u && pos > root_name_size && detail::is_directory_separator(p.m_pathname[pos - 1]) && !is_root_separator(p.m_pathname, root_dir_pos, pos - 1))
+            return detail::dot_path();
+    }
+
+    const value_type* ptr = p.m_pathname.c_str() + pos;
+    return path(ptr, ptr + filename_size);
+}
+
+BOOST_FILESYSTEM_DECL path_algorithms::string_type::size_type path_algorithms::find_filename_v4_size(path const& p)
+{
+    const size_type size = p.m_pathname.size();
+    size_type root_name_size = 0;
+    find_root_directory_start(p.m_pathname.c_str(), size, root_name_size);
+    return find_filename_size(p.m_pathname, root_name_size, size);
+}
+
+BOOST_FILESYSTEM_DECL path path_algorithms::stem_v3(path const& p)
+{
+    path name(path_algorithms::filename_v3(p));
+    if (path_algorithms::compare_v4(name, detail::dot_path()) != 0 && path_algorithms::compare_v4(name, detail::dot_dot_path()) != 0)
+    {
+        size_type pos = name.m_pathname.rfind(path::dot);
+        if (pos != string_type::npos)
+            name.m_pathname.erase(name.m_pathname.begin() + pos, name.m_pathname.end());
+    }
+    return name;
+}
+
+BOOST_FILESYSTEM_DECL path path_algorithms::stem_v4(path const& p)
+{
+    path name(path_algorithms::filename_v4(p));
+    if (path_algorithms::compare_v4(name, detail::dot_path()) != 0 && path_algorithms::compare_v4(name, detail::dot_dot_path()) != 0)
+    {
+        size_type pos = name.m_pathname.rfind(path::dot);
+        if (pos != 0 && pos != string_type::npos)
+            name.m_pathname.erase(name.m_pathname.begin() + pos, name.m_pathname.end());
+    }
+    return name;
+}
+
+BOOST_FILESYSTEM_DECL path path_algorithms::extension_v3(path const& p)
+{
+    path name(path_algorithms::filename_v3(p));
+    if (path_algorithms::compare_v4(name, detail::dot_path()) == 0 || path_algorithms::compare_v4(name, detail::dot_dot_path()) == 0)
+        return path();
+    size_type pos(name.m_pathname.rfind(path::dot));
+    return pos == string_type::npos ? path() : path(name.m_pathname.c_str() + pos);
+}
+
+BOOST_FILESYSTEM_DECL path_algorithms::string_type::size_type path_algorithms::find_extension_v4_size(path const& p)
+{
+    const size_type size = p.m_pathname.size();
+    size_type root_name_size = 0;
+    find_root_directory_start(p.m_pathname.c_str(), size, root_name_size);
+    size_type filename_size = find_filename_size(p.m_pathname, root_name_size, size);
+    size_type filename_pos = size - filename_size;
+    if
+    (
+        filename_size > 0u &&
+        // Check for "." and ".." filenames
+        !(p.m_pathname[filename_pos] == path::dot &&
+            (filename_size == 1u || (filename_size == 2u && p.m_pathname[filename_pos + 1u] == path::dot)))
+    )
+    {
+        size_type ext_pos = size;
+        while (ext_pos > filename_pos)
+        {
+            --ext_pos;
+            if (p.m_pathname[ext_pos] == path::dot)
+                break;
+        }
+
+        if (ext_pos > filename_pos)
+            return size - ext_pos;
+    }
+
+    return 0u;
+}
+
+} // namespace detail
+
+BOOST_FILESYSTEM_DECL path& path::remove_filename_and_trailing_separators()
+{
+    size_type end_pos = detail::path_algorithms::find_parent_path_size(*this);
+    m_pathname.erase(m_pathname.begin() + end_pos, m_pathname.end());
+    return *this;
+}
+
+BOOST_FILESYSTEM_DECL path& path::remove_trailing_separator()
+{
+    if (!m_pathname.empty() && detail::is_directory_separator(m_pathname[m_pathname.size() - 1]))
+        m_pathname.erase(m_pathname.end() - 1);
+    return *this;
+}
+
+BOOST_FILESYSTEM_DECL path& path::replace_filename(path const& replacement)
+{
+    detail::path_algorithms::remove_filename_v4(*this);
+    detail::path_algorithms::append_v4(*this, replacement.m_pathname.data(), replacement.m_pathname.data() + replacement.m_pathname.size());
+    return *this;
+}
+
+//  lexical operations  --------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL path path::lexically_relative(path const& base) const
+{
+    path::iterator b = begin(), e = end(), base_b = base.begin(), base_e = base.end();
+    std::pair< path::iterator, path::iterator > mm = detail::mismatch(b, e, base_b, base_e);
+    if (mm.first == b && mm.second == base_b)
+        return path();
+    if (mm.first == e && mm.second == base_e)
+        return detail::dot_path();
+
+    std::ptrdiff_t n = 0;
+    for (; mm.second != base_e; detail::path_algorithms::increment_v4(mm.second))
+    {
+        path const& p = *mm.second;
+        if (detail::path_algorithms::compare_v4(p, detail::dot_dot_path()) == 0)
+            --n;
+        else if (!p.empty() && detail::path_algorithms::compare_v4(p, detail::dot_path()) != 0)
+            ++n;
+    }
+    if (n < 0)
+        return path();
+    if (n == 0 && (mm.first == e || mm.first->empty()))
+        return detail::dot_path();
+
+    path tmp;
+    for (; n > 0; --n)
+        detail::path_algorithms::append_v4(tmp, detail::dot_dot_path());
+    for (; mm.first != e; detail::path_algorithms::increment_v4(mm.first))
+        detail::path_algorithms::append_v4(tmp, *mm.first);
+    return tmp;
+}
+
+} // namespace filesystem
+} // namespace boost
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//                         class path helpers implementation                            //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+namespace {
+
+//  is_root_separator  ---------------------------------------------------------------//
+
+// pos is position of the separator
+inline bool is_root_separator(string_type const& str, size_type root_dir_pos, size_type pos)
+{
+    BOOST_ASSERT_MSG(pos < str.size() && fs::detail::is_directory_separator(str[pos]), "precondition violation");
+
+    // root_dir_pos points at the leftmost separator, we need to skip any duplicate separators right of root dir
+    while (pos > root_dir_pos && fs::detail::is_directory_separator(str[pos - 1]))
+        --pos;
+
+    return pos == root_dir_pos;
+}
+
+//  find_filename_size  --------------------------------------------------------------//
+
+// Returns: Size of the filename element that ends at end_pos (which is past-the-end position). 0 if no filename found.
+inline size_type find_filename_size(string_type const& str, size_type root_name_size, size_type end_pos)
+{
+    size_type pos = end_pos;
+    while (pos > root_name_size)
+    {
+        --pos;
+
+        if (fs::detail::is_directory_separator(str[pos]))
+        {
+            ++pos; // filename starts past the separator
+            break;
+        }
+    }
+
+    return end_pos - pos;
+}
+
+//  find_root_directory_start  -------------------------------------------------------//
+
+// Returns: starting position of root directory or size if not found
+size_type find_root_directory_start(const value_type* path, size_type size, size_type& root_name_size)
+{
+    root_name_size = 0;
+    if (size == 0)
+        return 0;
+
+    bool parsing_root_name = false;
+    size_type pos = 0;
+
+    // case "//", possibly followed by more characters
+    if (fs::detail::is_directory_separator(path[0]))
+    {
+        if (size >= 2 && fs::detail::is_directory_separator(path[1]))
+        {
+            if (size == 2)
+            {
+                // The whole path is just a pair of separators
+                root_name_size = 2;
+                return 2;
+            }
+#ifdef BOOST_WINDOWS_API
+            // https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file
+            // cases "\\?\" and "\\.\"
+            else if (size >= 4 && (path[2] == questionmark || path[2] == fs::path::dot) && fs::detail::is_directory_separator(path[3]))
+            {
+                parsing_root_name = true;
+                pos += 4;
+            }
+#endif
+            else if (fs::detail::is_directory_separator(path[2]))
+            {
+                // The path starts with three directory separators, which is interpreted as a root directory followed by redundant separators
+                return 0;
+            }
+            else
+            {
+                // case "//net {/}"
+                parsing_root_name = true;
+                pos += 2;
+                goto find_next_separator;
+            }
+        }
+#ifdef BOOST_WINDOWS_API
+        // https://stackoverflow.com/questions/23041983/path-prefixes-and
+        // case "\??\" (NT path prefix)
+        else if (size >= 4 && path[1] == questionmark && path[2] == questionmark && fs::detail::is_directory_separator(path[3]))
+        {
+            parsing_root_name = true;
+            pos += 4;
+        }
+#endif
+        else
+        {
+            // The path starts with a separator, possibly followed by a non-separator character
+            return 0;
+        }
+    }
+
+#ifdef BOOST_WINDOWS_API
+    // case "c:" or "prn:"
+    // Note: There is ambiguity in a "c:x" path interpretation. It could either mean a file "x" located at the current directory for drive C:,
+    //       or an alternative stream "x" of a file "c". Windows API resolve this as the former, and so do we.
+    if ((size - pos) >= 2 && fs::detail::is_letter(path[pos]))
+    {
+        size_type i = pos + 1;
+        for (; i < size; ++i)
+        {
+            if (!is_device_name_char(path[i]))
+                break;
+        }
+
+        if (i < size && path[i] == colon)
+        {
+            pos = i + 1;
+            root_name_size = pos;
+            parsing_root_name = false;
+
+            if (pos < size && fs::detail::is_directory_separator(path[pos]))
+                return pos;
+        }
+    }
+#endif
+
+    if (!parsing_root_name)
+        return size;
+
+find_next_separator:
+    pos += find_separator(path + pos, size - pos);
+    if (parsing_root_name)
+        root_name_size = pos;
+
+    return pos;
+}
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//                        class path::iterator implementation                           //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+//  first_element ----------------------------------------------------------------------//
+
+//   sets pos and len of first element, excluding extra separators
+//   if src.empty(), sets pos,len, to 0,0.
+void first_element(string_type const& src, size_type& element_pos, size_type& element_size, size_type size)
+{
+    element_pos = 0;
+    element_size = 0;
+    if (src.empty())
+        return;
+
+    size_type root_name_size = 0;
+    size_type root_dir_pos = find_root_directory_start(src.c_str(), size, root_name_size);
+
+    // First element is the root name, if there is one
+    if (root_name_size > 0)
+    {
+        element_size = root_name_size;
+        return;
+    }
+
+    // Otherwise, the root directory
+    if (root_dir_pos < size)
+    {
+        element_pos = root_dir_pos;
+        element_size = 1u;
+        return;
+    }
+
+    // Otherwise, the first filename or directory name in a relative path
+    size_type end_pos = src.find_first_of(separators);
+    if (end_pos == string_type::npos)
+        end_pos = src.size();
+    element_size = end_pos;
+}
+
+} // unnamed namespace
+
+namespace boost {
+namespace filesystem {
+namespace detail {
+
+BOOST_FILESYSTEM_DECL void path_algorithms::increment_v3(path_detail::path_iterator& it)
+{
+    const size_type size = it.m_path_ptr->m_pathname.size();
+    BOOST_ASSERT_MSG(it.m_pos < size, "path::iterator increment past end()");
+
+    // increment to position past current element; if current element is implicit dot,
+    // this will cause m_pos to represent the end iterator
+    it.m_pos += it.m_element.m_pathname.size();
+
+    // if the end is reached, we are done
+    if (it.m_pos >= size)
+    {
+        BOOST_ASSERT_MSG(it.m_pos == size, "path::iterator increment after the referenced path was modified");
+        it.m_element.clear(); // aids debugging
+        return;
+    }
+
+    // process separator (Windows drive spec is only case not a separator)
+    if (detail::is_directory_separator(it.m_path_ptr->m_pathname[it.m_pos]))
+    {
+        size_type root_name_size = 0;
+        size_type root_dir_pos = find_root_directory_start(it.m_path_ptr->m_pathname.c_str(), size, root_name_size);
+
+        // detect root directory and set iterator value to the separator if it is
+        if (it.m_pos == root_dir_pos && it.m_element.m_pathname.size() == root_name_size)
+        {
+            it.m_element.m_pathname = path::separator; // generic format; see docs
+            return;
+        }
+
+        // skip separators until m_pos points to the start of the next element
+        while (it.m_pos != size && detail::is_directory_separator(it.m_path_ptr->m_pathname[it.m_pos]))
+        {
+            ++it.m_pos;
+        }
+
+        // detect trailing separator, and treat it as ".", per POSIX spec
+        if (it.m_pos == size &&
+            !is_root_separator(it.m_path_ptr->m_pathname, root_dir_pos, it.m_pos - 1))
+        {
+            --it.m_pos;
+            it.m_element = detail::dot_path();
+            return;
+        }
+    }
+
+    // get m_element
+    size_type end_pos = it.m_path_ptr->m_pathname.find_first_of(separators, it.m_pos);
+    if (end_pos == string_type::npos)
+        end_pos = size;
+    const path::value_type* p = it.m_path_ptr->m_pathname.c_str();
+    it.m_element.m_pathname.assign(p + it.m_pos, p + end_pos);
+}
+
+BOOST_FILESYSTEM_DECL void path_algorithms::increment_v4(path_detail::path_iterator& it)
+{
+    const size_type size = it.m_path_ptr->m_pathname.size();
+    BOOST_ASSERT_MSG(it.m_pos <= size, "path::iterator increment past end()");
+
+    if (it.m_element.m_pathname.empty() && (it.m_pos + 1) == size && detail::is_directory_separator(it.m_path_ptr->m_pathname[it.m_pos]))
+    {
+        // The iterator was pointing to the last empty element of the path; set to end.
+        it.m_pos = size;
+        return;
+    }
+
+    // increment to position past current element; if current element is implicit dot,
+    // this will cause m_pos to represent the end iterator
+    it.m_pos += it.m_element.m_pathname.size();
+
+    // if the end is reached, we are done
+    if (it.m_pos >= size)
+    {
+        BOOST_ASSERT_MSG(it.m_pos == size, "path::iterator increment after the referenced path was modified");
+        it.m_element.clear(); // aids debugging
+        return;
+    }
+
+    // process separator (Windows drive spec is only case not a separator)
+    if (detail::is_directory_separator(it.m_path_ptr->m_pathname[it.m_pos]))
+    {
+        size_type root_name_size = 0;
+        size_type root_dir_pos = find_root_directory_start(it.m_path_ptr->m_pathname.c_str(), size, root_name_size);
+
+        // detect root directory and set iterator value to the separator if it is
+        if (it.m_pos == root_dir_pos && it.m_element.m_pathname.size() == root_name_size)
+        {
+            it.m_element.m_pathname = path::separator; // generic format; see docs
+            return;
+        }
+
+        // skip separators until m_pos points to the start of the next element
+        while (it.m_pos != size && detail::is_directory_separator(it.m_path_ptr->m_pathname[it.m_pos]))
+        {
+            ++it.m_pos;
+        }
+
+        // detect trailing separator
+        if (it.m_pos == size &&
+            !is_root_separator(it.m_path_ptr->m_pathname, root_dir_pos, it.m_pos - 1))
+        {
+            --it.m_pos;
+            it.m_element.m_pathname.clear();
+            return;
+        }
+    }
+
+    // get m_element
+    size_type end_pos = it.m_path_ptr->m_pathname.find_first_of(separators, it.m_pos);
+    if (end_pos == string_type::npos)
+        end_pos = size;
+    const path::value_type* p = it.m_path_ptr->m_pathname.c_str();
+    it.m_element.m_pathname.assign(p + it.m_pos, p + end_pos);
+}
+
+BOOST_FILESYSTEM_DECL void path_algorithms::decrement_v3(path_detail::path_iterator& it)
+{
+    const size_type size = it.m_path_ptr->m_pathname.size();
+    BOOST_ASSERT_MSG(it.m_pos > 0, "path::iterator decrement past begin()");
+    BOOST_ASSERT_MSG(it.m_pos <= size, "path::iterator decrement after the referenced path was modified");
+
+    size_type root_name_size = 0;
+    size_type root_dir_pos = find_root_directory_start(it.m_path_ptr->m_pathname.c_str(), size, root_name_size);
+
+    if (root_dir_pos < size && it.m_pos == root_dir_pos)
+    {
+        // Was pointing at root directory, decrement to root name
+    set_to_root_name:
+        it.m_pos = 0u;
+        const path::value_type* p = it.m_path_ptr->m_pathname.c_str();
+        it.m_element.m_pathname.assign(p, p + root_name_size);
+        return;
+    }
+
+    // if at end and there was a trailing non-root '/', return "."
+    if (it.m_pos == size &&
+        size > 1 &&
+        detail::is_directory_separator(it.m_path_ptr->m_pathname[it.m_pos - 1]) &&
+        !is_root_separator(it.m_path_ptr->m_pathname, root_dir_pos, it.m_pos - 1))
+    {
+        --it.m_pos;
+        it.m_element = detail::dot_path();
+        return;
+    }
+
+    // skip separators unless root directory
+    size_type end_pos = it.m_pos;
+    while (end_pos > root_name_size)
+    {
+        --end_pos;
+
+        if (end_pos == root_dir_pos)
+        {
+            // Decremented to the root directory
+            it.m_pos = end_pos;
+            it.m_element.m_pathname = path::separator; // generic format; see docs
+            return;
+        }
+
+        if (!detail::is_directory_separator(it.m_path_ptr->m_pathname[end_pos]))
+        {
+            ++end_pos;
+            break;
+        }
+    }
+
+    if (end_pos <= root_name_size)
+        goto set_to_root_name;
+
+    size_type filename_size = find_filename_size(it.m_path_ptr->m_pathname, root_name_size, end_pos);
+    it.m_pos = end_pos - filename_size;
+    const path::value_type* p = it.m_path_ptr->m_pathname.c_str();
+    it.m_element.m_pathname.assign(p + it.m_pos, p + end_pos);
+}
+
+BOOST_FILESYSTEM_DECL void path_algorithms::decrement_v4(path_detail::path_iterator& it)
+{
+    const size_type size = it.m_path_ptr->m_pathname.size();
+    BOOST_ASSERT_MSG(it.m_pos > 0, "path::iterator decrement past begin()");
+    BOOST_ASSERT_MSG(it.m_pos <= size, "path::iterator decrement after the referenced path was modified");
+
+    size_type root_name_size = 0;
+    size_type root_dir_pos = find_root_directory_start(it.m_path_ptr->m_pathname.c_str(), size, root_name_size);
+
+    if (root_dir_pos < size && it.m_pos == root_dir_pos)
+    {
+        // Was pointing at root directory, decrement to root name
+    set_to_root_name:
+        it.m_pos = 0u;
+        const path::value_type* p = it.m_path_ptr->m_pathname.c_str();
+        it.m_element.m_pathname.assign(p, p + root_name_size);
+        return;
+    }
+
+    // if at end and there was a trailing '/', return ""
+    if (it.m_pos == size &&
+        size > 1 &&
+        detail::is_directory_separator(it.m_path_ptr->m_pathname[it.m_pos - 1]) &&
+        !is_root_separator(it.m_path_ptr->m_pathname, root_dir_pos, it.m_pos - 1))
+    {
+        --it.m_pos;
+        it.m_element.m_pathname.clear();
+        return;
+    }
+
+    // skip separators unless root directory
+    size_type end_pos = it.m_pos;
+    while (end_pos > root_name_size)
+    {
+        --end_pos;
+
+        if (end_pos == root_dir_pos)
+        {
+            // Decremented to the root directory
+            it.m_pos = end_pos;
+            it.m_element.m_pathname = path::separator; // generic format; see docs
+            return;
+        }
+
+        if (!detail::is_directory_separator(it.m_path_ptr->m_pathname[end_pos]))
+        {
+            ++end_pos;
+            break;
+        }
+    }
+
+    if (end_pos <= root_name_size)
+        goto set_to_root_name;
+
+    size_type filename_size = find_filename_size(it.m_path_ptr->m_pathname, root_name_size, end_pos);
+    it.m_pos = end_pos - filename_size;
+    const path::value_type* p = it.m_path_ptr->m_pathname.c_str();
+    it.m_element.m_pathname.assign(p + it.m_pos, p + end_pos);
+}
+
+} // namespace detail
+
+//  path iterators  ------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL path::iterator path::begin() const
+{
+    iterator itr;
+    itr.m_path_ptr = this;
+
+    size_type element_size;
+    first_element(m_pathname, itr.m_pos, element_size);
+
+    if (element_size > 0)
+    {
+        itr.m_element = m_pathname.substr(itr.m_pos, element_size);
+#ifdef BOOST_WINDOWS_API
+        if (itr.m_element.m_pathname.size() == 1u && itr.m_element.m_pathname[0] == path::preferred_separator)
+            itr.m_element.m_pathname[0] = path::separator;
+#endif
+    }
+
+    return itr;
+}
+
+BOOST_FILESYSTEM_DECL path::iterator path::end() const
+{
+    iterator itr;
+    itr.m_path_ptr = this;
+    itr.m_pos = m_pathname.size();
+    return itr;
+}
+
+} // namespace filesystem
+} // namespace boost
+
+namespace {
+
+//------------------------------------------------------------------------------------//
+//                                locale helpers                                      //
+//------------------------------------------------------------------------------------//
+
+//  Prior versions of these locale and codecvt implementations tried to take advantage
+//  of static initialization where possible, kept a local copy of the current codecvt
+//  facet (to avoid codecvt() having to call use_facet()), and was not multi-threading
+//  safe (again for efficiency).
+//
+//  This was error prone, and required different implementation techniques depending
+//  on the compiler and also whether static or dynamic linking was used. Furthermore,
+//  users could not easily provide their multi-threading safe wrappers because the
+//  path interface requires the implementation itself to call codecvt() to obtain the
+//  default facet, and the initialization of the static within path_locale() could race.
+//
+//  The code below is portable to all platforms, is much simpler, and hopefully will be
+//  much more robust. Timing tests (on Windows, using a Visual C++ release build)
+//  indicated the current code is roughly 9% slower than the previous code, and that
+//  seems a small price to pay for better code that is easier to use.
+
+std::locale default_locale()
+{
+#if defined(BOOST_WINDOWS_API)
+    std::locale global_loc = std::locale();
+    return std::locale(global_loc, new boost::filesystem::detail::windows_file_codecvt());
+#elif defined(macintosh) || defined(__APPLE__) || defined(__APPLE_CC__) || defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__HAIKU__)
+    // "All BSD system functions expect their string parameters to be in UTF-8 encoding
+    // and nothing else." See
+    // http://developer.apple.com/mac/library/documentation/MacOSX/Conceptual/BPInternational/Articles/FileEncodings.html
+    //
+    // "The kernel will reject any filename that is not a valid UTF-8 string, and it will
+    // even be normalized (to Unicode NFD) before stored on disk, at least when using HFS.
+    // The right way to deal with it would be to always convert the filename to UTF-8
+    // before trying to open/create a file." See
+    // http://lists.apple.com/archives/unix-porting/2007/Sep/msg00023.html
+    //
+    // "How a file name looks at the API level depends on the API. Current Carbon APIs
+    // handle file names as an array of UTF-16 characters; POSIX ones handle them as an
+    // array of UTF-8, which is why UTF-8 works well in Terminal. How it's stored on disk
+    // depends on the disk format; HFS+ uses UTF-16, but that's not important in most
+    // cases." See
+    // http://lists.apple.com/archives/applescript-users/2002/Sep/msg00319.html
+    //
+    // Many thanks to Peter Dimov for digging out the above references!
+
+    std::locale global_loc = std::locale();
+    return std::locale(global_loc, new boost::filesystem::detail::utf8_codecvt_facet());
+#else // Other POSIX
+    // ISO C calls std::locale("") "the locale-specific native environment", and this
+    // locale is the default for many POSIX-based operating systems such as Linux.
+    return std::locale("");
+#endif
+}
+
+std::locale* g_path_locale = nullptr;
+
+void schedule_path_locale_cleanup() noexcept;
+
+// std::locale("") construction, needed on non-Apple POSIX systems, can throw
+// (if environmental variables LC_MESSAGES or LANG are wrong, for example), so
+// get_path_locale() provides lazy initialization to ensure that any
+// exceptions occur after main() starts and so can be caught. Furthermore,
+// g_path_locale is only initialized if path::codecvt() or path::imbue() are themselves
+// actually called, ensuring that an exception will only be thrown if std::locale("")
+// is really needed.
+inline std::locale& get_path_locale()
+{
+#if !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+    atomic_ns::atomic_ref< std::locale* > a(g_path_locale);
+    std::locale* p = a.load(atomic_ns::memory_order_acquire);
+    if (BOOST_UNLIKELY(!p))
+    {
+        std::locale* new_p = new std::locale(default_locale());
+        if (a.compare_exchange_strong(p, new_p, atomic_ns::memory_order_acq_rel, atomic_ns::memory_order_acquire))
+        {
+            p = new_p;
+            schedule_path_locale_cleanup();
+        }
+        else
+        {
+            delete new_p;
+        }
+    }
+    return *p;
+#else // !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+    std::locale* p = g_path_locale;
+    if (BOOST_UNLIKELY(!p))
+    {
+        g_path_locale = p = new std::locale(default_locale());
+        schedule_path_locale_cleanup();
+    }
+    return *p;
+#endif // !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+}
+
+inline std::locale* replace_path_locale(std::locale const& loc)
+{
+    std::locale* new_p = new std::locale(loc);
+#if !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+    std::locale* p = atomic_ns::atomic_ref< std::locale* >(g_path_locale).exchange(new_p, atomic_ns::memory_order_acq_rel);
+#else
+    std::locale* p = g_path_locale;
+    g_path_locale = new_p;
+#endif
+    if (!p)
+        schedule_path_locale_cleanup();
+    return p;
+}
+
+#if defined(_MSC_VER)
+
+const boost::filesystem::path* g_dot_path = nullptr;
+const boost::filesystem::path* g_dot_dot_path = nullptr;
+
+inline void schedule_path_locale_cleanup() noexcept
+{
+}
+
+inline boost::filesystem::path const& get_dot_path()
+{
+#if !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+    atomic_ns::atomic_ref< const boost::filesystem::path* > a(g_dot_path);
+    const boost::filesystem::path* p = a.load(atomic_ns::memory_order_acquire);
+    if (BOOST_UNLIKELY(!p))
+    {
+        const boost::filesystem::path* new_p = new boost::filesystem::path(dot_path_literal);
+        if (a.compare_exchange_strong(p, new_p, atomic_ns::memory_order_acq_rel, atomic_ns::memory_order_acquire))
+            p = new_p;
+        else
+            delete new_p;
+    }
+    return *p;
+#else // !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+    const boost::filesystem::path* p = g_dot_path;
+    if (BOOST_UNLIKELY(!p))
+        g_dot_path = p = new boost::filesystem::path(dot_path_literal);
+    return *p;
+#endif // !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+}
+
+inline boost::filesystem::path const& get_dot_dot_path()
+{
+#if !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+    atomic_ns::atomic_ref< const boost::filesystem::path* > a(g_dot_dot_path);
+    const boost::filesystem::path* p = a.load(atomic_ns::memory_order_acquire);
+    if (BOOST_UNLIKELY(!p))
+    {
+        const boost::filesystem::path* new_p = new boost::filesystem::path(dot_dot_path_literal);
+        if (a.compare_exchange_strong(p, new_p, atomic_ns::memory_order_acq_rel, atomic_ns::memory_order_acquire))
+            p = new_p;
+        else
+            delete new_p;
+    }
+    return *p;
+#else // !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+    const boost::filesystem::path* p = g_dot_dot_path;
+    if (BOOST_UNLIKELY(!p))
+        g_dot_dot_path = p = new boost::filesystem::path(dot_dot_path_literal);
+    return *p;
+#endif // !defined(BOOST_FILESYSTEM_SINGLE_THREADED)
+}
+
+void __cdecl destroy_path_globals()
+{
+    delete g_dot_dot_path;
+    g_dot_dot_path = nullptr;
+    delete g_dot_path;
+    g_dot_path = nullptr;
+    delete g_path_locale;
+    g_path_locale = nullptr;
+}
+
+BOOST_FILESYSTEM_INIT_FUNC init_path_globals()
+{
+#if !defined(BOOST_SYSTEM_HAS_CONSTEXPR)
+    // codecvt_error_category needs to be called early to dynamic-initialize the error category instance
+    boost::filesystem::codecvt_error_category();
+#endif
+    std::atexit(&destroy_path_globals);
+    return BOOST_FILESYSTEM_INITRETSUCCESS_V;
+}
+
+#if _MSC_VER >= 1400
+
+#pragma section(".CRT$XCM", long, read)
+__declspec(allocate(".CRT$XCM")) BOOST_ATTRIBUTE_UNUSED BOOST_FILESYSTEM_ATTRIBUTE_RETAIN
+extern const init_func_ptr_t p_init_path_globals = &init_path_globals;
+
+#else // _MSC_VER >= 1400
+
+#if (_MSC_VER >= 1300) // 1300 == VC++ 7.0
+#pragma data_seg(push, old_seg)
+#endif
+#pragma data_seg(".CRT$XCM")
+BOOST_ATTRIBUTE_UNUSED BOOST_FILESYSTEM_ATTRIBUTE_RETAIN
+extern const init_func_ptr_t p_init_path_globals = &init_path_globals;
+#pragma data_seg()
+#if (_MSC_VER >= 1300) // 1300 == VC++ 7.0
+#pragma data_seg(pop, old_seg)
+#endif
+
+#endif // _MSC_VER >= 1400
+
+#if defined(BOOST_FILESYSTEM_NO_ATTRIBUTE_RETAIN)
+//! Makes sure the global initializer pointers are referenced and not removed by linker
+struct globals_retainer
+{
+    const init_func_ptr_t* volatile m_p_init_path_globals;
+
+    globals_retainer() { m_p_init_path_globals = &p_init_path_globals; }
+};
+BOOST_ATTRIBUTE_UNUSED
+static const globals_retainer g_globals_retainer;
+#endif // defined(BOOST_FILESYSTEM_NO_ATTRIBUTE_RETAIN)
+
+#else // defined(_MSC_VER)
+
+struct path_locale_deleter
+{
+    ~path_locale_deleter()
+    {
+        delete g_path_locale;
+        g_path_locale = nullptr;
+    }
+};
+
+#if defined(BOOST_FILESYSTEM_HAS_INIT_PRIORITY)
+
+BOOST_FILESYSTEM_INIT_PRIORITY(BOOST_FILESYSTEM_PATH_GLOBALS_INIT_PRIORITY) BOOST_ATTRIBUTE_UNUSED
+const path_locale_deleter g_path_locale_deleter = {};
+BOOST_FILESYSTEM_INIT_PRIORITY(BOOST_FILESYSTEM_PATH_GLOBALS_INIT_PRIORITY)
+const boost::filesystem::path g_dot_path(dot_path_literal);
+BOOST_FILESYSTEM_INIT_PRIORITY(BOOST_FILESYSTEM_PATH_GLOBALS_INIT_PRIORITY)
+const boost::filesystem::path g_dot_dot_path(dot_dot_path_literal);
+
+inline void schedule_path_locale_cleanup() noexcept
+{
+}
+
+inline boost::filesystem::path const& get_dot_path()
+{
+    return g_dot_path;
+}
+
+inline boost::filesystem::path const& get_dot_dot_path()
+{
+    return g_dot_dot_path;
+}
+
+#else // defined(BOOST_FILESYSTEM_HAS_INIT_PRIORITY)
+
+inline void schedule_path_locale_cleanup() noexcept
+{
+    BOOST_ATTRIBUTE_UNUSED static const path_locale_deleter g_path_locale_deleter;
+}
+
+inline boost::filesystem::path const& get_dot_path()
+{
+    static const boost::filesystem::path g_dot_path(dot_path_literal);
+    return g_dot_path;
+}
+
+inline boost::filesystem::path const& get_dot_dot_path()
+{
+    static const boost::filesystem::path g_dot_dot_path(dot_dot_path_literal);
+    return g_dot_dot_path;
+}
+
+#endif // defined(BOOST_FILESYSTEM_HAS_INIT_PRIORITY)
+
+#endif // defined(_MSC_VER)
+
+} // unnamed namespace
+
+//--------------------------------------------------------------------------------------//
+//              path::codecvt() and path::imbue() implementation                        //
+//--------------------------------------------------------------------------------------//
+
+namespace boost {
+namespace filesystem {
+
+BOOST_FILESYSTEM_DECL path::codecvt_type const& path::codecvt()
+{
+#ifdef BOOST_FILESYSTEM_DEBUG
+    std::cout << "***** path::codecvt() called" << std::endl;
+#endif
+    return std::use_facet< std::codecvt< wchar_t, char, std::mbstate_t > >(get_path_locale());
+}
+
+BOOST_FILESYSTEM_DECL std::locale path::imbue(std::locale const& loc)
+{
+#ifdef BOOST_FILESYSTEM_DEBUG
+    std::cout << "***** path::imbue() called" << std::endl;
+#endif
+    std::locale* p = replace_path_locale(loc);
+    if (BOOST_LIKELY(p != nullptr))
+    {
+        // Note: copying/moving std::locale does not throw
+        std::locale temp(std::move(*p));
+        delete p;
+        return temp;
+    }
+
+    return default_locale();
+}
+
+namespace detail {
+
+BOOST_FILESYSTEM_DECL path const& dot_path()
+{
+    return get_dot_path();
+}
+
+BOOST_FILESYSTEM_DECL path const& dot_dot_path()
+{
+    return get_dot_dot_path();
+}
+
+} // namespace detail
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
diff --git a/contrib/restricted/boost/filesystem/src/path_traits.cpp b/contrib/restricted/boost/filesystem/src/path_traits.cpp
new file mode 100644
index 0000000000..9a68f25872
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/path_traits.cpp
@@ -0,0 +1,187 @@
+//  filesystem path_traits.cpp  --------------------------------------------------------//
+
+//  Copyright Beman Dawes 2008, 2009
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  Library home page: http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#include "platform_config.hpp"
+
+#include <boost/filesystem/config.hpp>
+#include <boost/filesystem/detail/path_traits.hpp>
+#include <boost/filesystem/path.hpp>
+#include <boost/system/system_error.hpp>
+#include <boost/assert.hpp>
+#include <memory>
+#include <string>
+#include <locale>  // for codecvt_base::result
+#include <cwchar>  // for mbstate_t
+#include <cstddef>
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+namespace pt = boost::filesystem::detail::path_traits;
+namespace fs = boost::filesystem;
+namespace bs = boost::system;
+
+//--------------------------------------------------------------------------------------//
+//                                  configuration                                       //
+//--------------------------------------------------------------------------------------//
+
+#ifndef BOOST_FILESYSTEM_CODECVT_BUF_SIZE
+#define BOOST_FILESYSTEM_CODECVT_BUF_SIZE 256
+#endif
+
+namespace {
+
+BOOST_CONSTEXPR_OR_CONST std::size_t default_codecvt_buf_size = BOOST_FILESYSTEM_CODECVT_BUF_SIZE;
+
+//--------------------------------------------------------------------------------------//
+//                                                                                      //
+//  The public convert() functions do buffer management, and then forward to the        //
+//  convert_aux() functions for the actual call to the codecvt facet.                   //
+//                                                                                      //
+//--------------------------------------------------------------------------------------//
+
+//--------------------------------------------------------------------------------------//
+//                      convert_aux const char* to wstring                             //
+//--------------------------------------------------------------------------------------//
+
+void convert_aux(const char* from, const char* from_end, wchar_t* to, wchar_t* to_end, std::wstring& target, pt::codecvt_type const& cvt)
+{
+    //std::cout << std::hex
+    //          << " from=" << std::size_t(from)
+    //          << " from_end=" << std::size_t(from_end)
+    //          << " to=" << std::size_t(to)
+    //          << " to_end=" << std::size_t(to_end)
+    //          << std::endl;
+
+    std::mbstate_t state = std::mbstate_t(); // perhaps unneeded, but cuts bug reports
+    const char* from_next;
+    wchar_t* to_next;
+
+    std::codecvt_base::result res;
+
+    if ((res = cvt.in(state, from, from_end, from_next, to, to_end, to_next)) != std::codecvt_base::ok)
+    {
+        //std::cout << " result is " << static_cast<int>(res) << std::endl;
+        BOOST_FILESYSTEM_THROW(bs::system_error(res, fs::codecvt_error_category(), "boost::filesystem::path codecvt to wstring"));
+    }
+    target.append(to, to_next);
+}
+
+//--------------------------------------------------------------------------------------//
+//                      convert_aux const wchar_t* to string                           //
+//--------------------------------------------------------------------------------------//
+
+void convert_aux(const wchar_t* from, const wchar_t* from_end, char* to, char* to_end, std::string& target, pt::codecvt_type const& cvt)
+{
+    //std::cout << std::hex
+    //          << " from=" << std::size_t(from)
+    //          << " from_end=" << std::size_t(from_end)
+    //          << " to=" << std::size_t(to)
+    //          << " to_end=" << std::size_t(to_end)
+    //          << std::endl;
+
+    std::mbstate_t state = std::mbstate_t(); // perhaps unneeded, but cuts bug reports
+    const wchar_t* from_next;
+    char* to_next;
+
+    std::codecvt_base::result res;
+
+    if ((res = cvt.out(state, from, from_end, from_next, to, to_end, to_next)) != std::codecvt_base::ok)
+    {
+        //std::cout << " result is " << static_cast<int>(res) << std::endl;
+        BOOST_FILESYSTEM_THROW(bs::system_error(res, fs::codecvt_error_category(), "boost::filesystem::path codecvt to string"));
+    }
+    target.append(to, to_next);
+}
+
+} // unnamed namespace
+
+//--------------------------------------------------------------------------------------//
+//                                   path_traits                                        //
+//--------------------------------------------------------------------------------------//
+
+namespace boost {
+namespace filesystem {
+namespace detail {
+namespace path_traits {
+
+//--------------------------------------------------------------------------------------//
+//                          convert const char* to wstring                              //
+//--------------------------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL
+void convert(const char* from, const char* from_end, std::wstring& to, const codecvt_type* cvt)
+{
+    if (from == from_end)
+        return;
+
+    BOOST_ASSERT(from != nullptr);
+    BOOST_ASSERT(from_end != nullptr);
+
+    if (!cvt)
+        cvt = &fs::path::codecvt();
+
+    std::size_t buf_size = (from_end - from) * 3; // perhaps too large, but that's OK
+
+    //  dynamically allocate a buffer only if source is unusually large
+    if (buf_size > default_codecvt_buf_size)
+    {
+        std::unique_ptr< wchar_t[] > buf(new wchar_t[buf_size]);
+        convert_aux(from, from_end, buf.get(), buf.get() + buf_size, to, *cvt);
+    }
+    else
+    {
+        wchar_t buf[default_codecvt_buf_size];
+        convert_aux(from, from_end, buf, buf + default_codecvt_buf_size, to, *cvt);
+    }
+}
+
+//--------------------------------------------------------------------------------------//
+//                         convert const wchar_t* to string                            //
+//--------------------------------------------------------------------------------------//
+
+BOOST_FILESYSTEM_DECL
+void convert(const wchar_t* from, const wchar_t* from_end, std::string& to, const codecvt_type* cvt)
+{
+    if (from == from_end)
+        return;
+
+    BOOST_ASSERT(from != nullptr);
+    BOOST_ASSERT(from_end != nullptr);
+
+    if (!cvt)
+        cvt = &fs::path::codecvt();
+
+    //  The codecvt length functions may not be implemented, and I don't really
+    //  understand them either. Thus this code is just a guess; if it turns
+    //  out the buffer is too small then an error will be reported and the code
+    //  will have to be fixed.
+    std::size_t buf_size = (from_end - from) * 4; // perhaps too large, but that's OK
+    buf_size += 4;                                // encodings like shift-JIS need some prefix space
+
+    //  dynamically allocate a buffer only if source is unusually large
+    if (buf_size > default_codecvt_buf_size)
+    {
+        std::unique_ptr< char[] > buf(new char[buf_size]);
+        convert_aux(from, from_end, buf.get(), buf.get() + buf_size, to, *cvt);
+    }
+    else
+    {
+        char buf[default_codecvt_buf_size];
+        convert_aux(from, from_end, buf, buf + default_codecvt_buf_size, to, *cvt);
+    }
+}
+
+} // namespace path_traits
+} // namespace detail
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
diff --git a/contrib/restricted/boost/filesystem/src/platform_config.hpp b/contrib/restricted/boost/filesystem/src/platform_config.hpp
new file mode 100644
index 0000000000..941338b0a7
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/platform_config.hpp
@@ -0,0 +1,83 @@
+//  platform_config.hpp  --------------------------------------------------------------------//
+
+//  Copyright 2020 Andrey Semashev
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  See library home page at http://www.boost.org/libs/filesystem
+
+#ifndef BOOST_FILESYSTEM_PLATFORM_CONFIG_HPP_
+#define BOOST_FILESYSTEM_PLATFORM_CONFIG_HPP_
+
+//  define 64-bit offset macros BEFORE including boost/config.hpp (see ticket #5355)
+#if defined(__ANDROID__) && defined(__ANDROID_API__) && __ANDROID_API__ < 24
+// Android fully supports 64-bit file offsets only for API 24 and above.
+//
+// Trying to define _FILE_OFFSET_BITS=64 for APIs below 24
+// leads to compilation failure for one or another reason,
+// depending on target Android API level, Android NDK version,
+// used STL, order of include paths and more.
+// For more information, please see:
+// - https://github.com/boostorg/filesystem/issues/65
+// - https://github.com/boostorg/filesystem/pull/69
+//
+// Android NDK developers consider it the expected behavior.
+// See their official position here:
+// - https://github.com/android-ndk/ndk/issues/501#issuecomment-326447479
+// - https://android.googlesource.com/platform/bionic/+/a34817457feee026e8702a1d2dffe9e92b51d7d1/docs/32-bit-abi.md#32_bit-abi-bugs
+//
+// Thus we do not define _FILE_OFFSET_BITS in such case.
+#else
+// Defining _FILE_OFFSET_BITS=64 should kick in 64-bit off_t's
+// (and thus st_size) on 32-bit systems that provide the Large File
+// Support (LFS) interface, such as Linux, Solaris, and IRIX.
+//
+// At the time of this comment writing (March 2018), on most systems
+// _FILE_OFFSET_BITS=64 definition is harmless:
+// either the definition is supported and enables 64-bit off_t,
+// or the definition is not supported and is ignored, in which case
+// off_t does not change its default size for the target system
+// (which may be 32-bit or 64-bit already).
+// Thus it makes sense to have _FILE_OFFSET_BITS=64 defined by default,
+// instead of listing every system that supports the definition.
+// Those few systems, on which _FILE_OFFSET_BITS=64 is harmful,
+// for example this definition causes compilation failure on those systems,
+// should be exempt from defining _FILE_OFFSET_BITS by adding
+// an appropriate #elif block above with the appropriate comment.
+//
+// _FILE_OFFSET_BITS must be defined before any headers are included
+// to ensure that the definition is available to all included headers.
+// That is required at least on Solaris, and possibly on other
+// systems as well.
+#define _FILE_OFFSET_BITS 64
+#endif
+
+#if defined(__APPLE__) || defined(__MACH__)
+// Enable newer ABI on Mac OS 10.5 and later, which is needed for struct stat to have birthtime members
+#define _DARWIN_USE_64_BIT_INODE 1
+#endif
+
+#ifndef _POSIX_PTHREAD_SEMANTICS
+#define _POSIX_PTHREAD_SEMANTICS // Sun readdir_r() needs this
+#endif
+
+#if !defined(_INCLUDE_STDCSOURCE_199901) && (defined(hpux) || defined(_hpux) || defined(__hpux))
+// For HP-UX, request that WCHAR_MAX and WCHAR_MIN be defined as macros,
+// not casts. See ticket 5048
+#define _INCLUDE_STDCSOURCE_199901
+#endif
+
+#if defined(_WIN32) || defined(_WIN64) || defined(__WIN32__) || defined(__TOS_WIN__) || defined(__WINDOWS__) || \
+    defined(__CYGWIN__)
+// Define target Windows version macros before including any other headers
+#include <boost/winapi/config.hpp>
+#endif
+
+#ifndef BOOST_SYSTEM_NO_DEPRECATED
+#define BOOST_SYSTEM_NO_DEPRECATED
+#endif
+
+#include <boost/filesystem/config.hpp>
+
+#endif // BOOST_FILESYSTEM_PLATFORM_CONFIG_HPP_
diff --git a/contrib/restricted/boost/filesystem/src/portability.cpp b/contrib/restricted/boost/filesystem/src/portability.cpp
new file mode 100644
index 0000000000..8e0e2e5d98
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/portability.cpp
@@ -0,0 +1,83 @@
+//  portability.cpp  -------------------------------------------------------------------//
+
+//  Copyright 2002-2005 Beman Dawes
+//  Use, modification, and distribution is subject to the Boost Software
+//  License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy
+//  at http://www.boost.org/LICENSE_1_0.txt)
+
+//  See library home page at http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#include "platform_config.hpp"
+
+#include <boost/filesystem/config.hpp>
+#include <boost/filesystem/path.hpp>
+
+#include <cstring> // SGI MIPSpro compilers need this
+#include <string>
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+namespace boost {
+namespace filesystem {
+
+namespace {
+
+BOOST_CONSTEXPR_OR_CONST char windows_invalid_chars[] =
+    "\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F"
+    "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1A\x1B\x1C\x1D\x1E\x1F"
+    "<>:\"/\\|";
+
+BOOST_CONSTEXPR_OR_CONST char posix_valid_chars[] =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789._-";
+
+} // unnamed namespace
+
+//  name_check functions  ----------------------------------------------//
+
+#ifdef BOOST_WINDOWS
+BOOST_FILESYSTEM_DECL bool native(std::string const& name)
+{
+    return windows_name(name);
+}
+#else
+BOOST_FILESYSTEM_DECL bool native(std::string const& name)
+{
+    return !name.empty() && name[0] != ' ' && name.find('/') == std::string::npos;
+}
+#endif
+
+BOOST_FILESYSTEM_DECL bool portable_posix_name(std::string const& name)
+{
+    return !name.empty() && name.find_first_not_of(posix_valid_chars, 0, sizeof(posix_valid_chars) - 1) == std::string::npos;
+}
+
+BOOST_FILESYSTEM_DECL bool windows_name(std::string const& name)
+{
+    // note that the terminating '\0' is part of the string - thus the size below
+    // is sizeof(windows_invalid_chars) rather than sizeof(windows_invalid_chars)-1.
+    return !name.empty() && name[0] != ' ' && name.find_first_of(windows_invalid_chars, 0, sizeof(windows_invalid_chars)) == std::string::npos
+        && *(name.end() - 1) != ' ' && (*(name.end() - 1) != '.' || name.size() == 1 || name == "..");
+}
+
+BOOST_FILESYSTEM_DECL bool portable_name(std::string const& name)
+{
+    return !name.empty() && (name == "." || name == ".." || (windows_name(name) && portable_posix_name(name) && name[0] != '.' && name[0] != '-'));
+}
+
+BOOST_FILESYSTEM_DECL bool portable_directory_name(std::string const& name)
+{
+    return name == "." || name == ".." || (portable_name(name) && name.find('.') == std::string::npos);
+}
+
+BOOST_FILESYSTEM_DECL bool portable_file_name(std::string const& name)
+{
+    std::string::size_type pos;
+    return portable_name(name) && name != "." && name != ".." && ((pos = name.find('.')) == std::string::npos || (name.find('.', pos + 1) == std::string::npos && (pos + 5) > name.size()));
+}
+
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
diff --git a/contrib/restricted/boost/filesystem/src/posix_tools.hpp b/contrib/restricted/boost/filesystem/src/posix_tools.hpp
new file mode 100644
index 0000000000..09af4d5889
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/posix_tools.hpp
@@ -0,0 +1,78 @@
+//  posix_tools.hpp  -------------------------------------------------------------------//
+
+//  Copyright 2021-2024 Andrey Semashev
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  See library home page at http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#ifndef BOOST_FILESYSTEM_SRC_POSIX_TOOLS_HPP_
+#define BOOST_FILESYSTEM_SRC_POSIX_TOOLS_HPP_
+
+#include "platform_config.hpp"
+#include <boost/filesystem/config.hpp>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <boost/scope/unique_fd.hpp>
+#include <boost/system/error_code.hpp>
+#include <boost/filesystem/path.hpp>
+#include <boost/filesystem/file_status.hpp>
+#include <boost/filesystem/directory.hpp>
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+namespace boost {
+namespace filesystem {
+namespace detail {
+
+//! Platform-specific parameters for directory iterator construction
+struct directory_iterator_params
+{
+#if defined(BOOST_FILESYSTEM_HAS_FDOPENDIR_NOFOLLOW)
+    //! File descriptor of the directory to iterate over. If not a negative value, the directory path is only used to generate paths returned by the iterator.
+    boost::scope::unique_fd dir_fd;
+#endif
+};
+
+//! status() implementation
+file_status status_impl
+(
+    path const& p,
+    system::error_code* ec
+#if defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS) || defined(BOOST_FILESYSTEM_USE_STATX)
+    , int basedir_fd = AT_FDCWD
+#endif
+);
+
+//! symlink_status() implementation
+file_status symlink_status_impl
+(
+    path const& p,
+    system::error_code* ec
+#if defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS) || defined(BOOST_FILESYSTEM_USE_STATX)
+    , int basedir_fd = AT_FDCWD
+#endif
+);
+
+#if defined(BOOST_POSIX_API)
+
+//! Opens a directory file and returns a file descriptor. Returns a negative value in case of error.
+boost::scope::unique_fd open_directory(path const& p, directory_options opts, system::error_code& ec);
+
+#if defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+//! Opens a directory file and returns a file descriptor. Returns a negative value in case of error.
+boost::scope::unique_fd openat_directory(int basedir_fd, path const& p, directory_options opts, system::error_code& ec);
+#endif // defined(BOOST_FILESYSTEM_HAS_POSIX_AT_APIS)
+
+#endif // defined(BOOST_POSIX_API)
+
+} // namespace detail
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
+
+#endif // BOOST_FILESYSTEM_SRC_POSIX_TOOLS_HPP_
diff --git a/contrib/restricted/boost/filesystem/src/private_config.hpp b/contrib/restricted/boost/filesystem/src/private_config.hpp
new file mode 100644
index 0000000000..c58d245ee1
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/private_config.hpp
@@ -0,0 +1,74 @@
+//  private_config.hpp  ----------------------------------------------------------------//
+
+//  Copyright 2021 Andrey Semashev
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  See library home page at http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#ifndef BOOST_FILESYSTEM_SRC_PRIVATE_CONFIG_HPP_
+#define BOOST_FILESYSTEM_SRC_PRIVATE_CONFIG_HPP_
+
+#include <boost/filesystem/config.hpp>
+
+#if defined(BOOST_FILESYSTEM_HAS_INIT_PRIORITY)
+#define BOOST_FILESYSTEM_INIT_PRIORITY(n) __attribute__ ((init_priority(n)))
+#else
+#define BOOST_FILESYSTEM_INIT_PRIORITY(n)
+#endif
+
+// According to https://gcc.gnu.org/bugzilla//show_bug.cgi?id=65115,
+// the default C++ object initializers priority is 65535. We would like to
+// initialize function pointers earlier than that (with lower priority values),
+// before the other global objects initializers are run. Other than this,
+// these priority values are arbitrary.
+#define BOOST_FILESYSTEM_FUNC_PTR_INIT_PRIORITY 32767
+
+// Path globals initialization priority
+#define BOOST_FILESYSTEM_PATH_GLOBALS_INIT_PRIORITY 32768
+
+#if defined(__has_feature) && defined(__has_attribute)
+#if __has_feature(memory_sanitizer) && __has_attribute(no_sanitize)
+#define BOOST_FILESYSTEM_NO_SANITIZE_MEMORY __attribute__ ((no_sanitize("memory")))
+#endif
+#endif // defined(__has_feature) && defined(__has_attribute)
+
+#ifndef BOOST_FILESYSTEM_NO_SANITIZE_MEMORY
+#define BOOST_FILESYSTEM_NO_SANITIZE_MEMORY
+#endif
+
+#if defined(_MSC_VER)
+#if _MSC_VER < 1300 || _MSC_VER > 1900 // 1300 == VC++ 7.0, 1900 == VC++ 14.0
+typedef void (__cdecl* init_func_ptr_t)();
+#define BOOST_FILESYSTEM_INITRETSUCCESS_V
+#define BOOST_FILESYSTEM_INIT_FUNC void __cdecl
+#else
+typedef int (__cdecl* init_func_ptr_t)();
+#define BOOST_FILESYSTEM_INITRETSUCCESS_V 0
+#define BOOST_FILESYSTEM_INIT_FUNC int __cdecl
+#endif
+#else // defined(_MSC_VER)
+typedef void (*init_func_ptr_t)();
+#define BOOST_FILESYSTEM_INITRETSUCCESS_V
+#define BOOST_FILESYSTEM_INIT_FUNC void
+#endif // defined(_MSC_VER)
+
+#if defined(__has_attribute)
+#if __has_attribute(__used__)
+#define BOOST_FILESYSTEM_ATTRIBUTE_RETAIN __attribute__ ((__used__))
+#endif
+#endif
+
+#if !defined(BOOST_FILESYSTEM_ATTRIBUTE_RETAIN) && defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) >= 402
+#define BOOST_FILESYSTEM_ATTRIBUTE_RETAIN __attribute__ ((__used__))
+#endif
+
+#if !defined(BOOST_FILESYSTEM_ATTRIBUTE_RETAIN)
+#define BOOST_FILESYSTEM_NO_ATTRIBUTE_RETAIN
+#define BOOST_FILESYSTEM_ATTRIBUTE_RETAIN
+#endif
+
+#endif // BOOST_FILESYSTEM_SRC_PRIVATE_CONFIG_HPP_
diff --git a/contrib/restricted/boost/filesystem/src/unique_path.cpp b/contrib/restricted/boost/filesystem/src/unique_path.cpp
new file mode 100644
index 0000000000..e98677fa70
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/unique_path.cpp
@@ -0,0 +1,351 @@
+//  filesystem unique_path.cpp  --------------------------------------------------------//
+
+//  Copyright Beman Dawes 2010
+//  Copyright Andrey Semashev 2020, 2024
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  Library home page: http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#include "platform_config.hpp"
+
+#include <boost/predef/library/c/cloudabi.h>
+#include <boost/predef/os/bsd/open.h>
+#include <boost/predef/os/bsd/free.h>
+
+#ifdef BOOST_POSIX_API
+
+#include <cerrno>
+#include <stddef.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#if !defined(BOOST_FILESYSTEM_DISABLE_ARC4RANDOM)
+#if BOOST_OS_BSD_OPEN >= BOOST_VERSION_NUMBER(2, 1, 0) || \
+    BOOST_OS_BSD_FREE >= BOOST_VERSION_NUMBER(8, 0, 0) || \
+    BOOST_LIB_C_CLOUDABI
+#include <stdlib.h>
+#define BOOST_FILESYSTEM_HAS_ARC4RANDOM
+#endif
+#endif // !defined(BOOST_FILESYSTEM_DISABLE_ARC4RANDOM)
+
+#if !defined(BOOST_FILESYSTEM_DISABLE_GETRANDOM)
+#if (defined(__linux__) || defined(__linux) || defined(linux)) && \
+    (!defined(__ANDROID__) || __ANDROID_API__ >= 28)
+#include <sys/syscall.h>
+#if defined(SYS_getrandom)
+#define BOOST_FILESYSTEM_HAS_GETRANDOM_SYSCALL
+#endif // defined(SYS_getrandom)
+#if defined(__has_include)
+#if __has_include(<sys/random.h>)
+#define BOOST_FILESYSTEM_HAS_GETRANDOM
+#endif
+#elif defined(__GLIBC__)
+#if __GLIBC_PREREQ(2, 25)
+#define BOOST_FILESYSTEM_HAS_GETRANDOM
+#endif
+#endif // BOOST_FILESYSTEM_HAS_GETRANDOM definition
+#if defined(BOOST_FILESYSTEM_HAS_GETRANDOM)
+#include <sys/random.h>
+#endif
+#endif // (defined(__linux__) || defined(__linux) || defined(linux)) && (!defined(__ANDROID__) || __ANDROID_API__ >= 28)
+#endif // !defined(BOOST_FILESYSTEM_DISABLE_GETRANDOM)
+
+#include <boost/scope/unique_fd.hpp>
+#include "posix_tools.hpp"
+
+#else  // BOOST_WINDOWS_API
+
+// We use auto-linking below to help users of static builds of Boost.Filesystem to link to whatever Windows SDK library we selected.
+// The dependency information is currently not exposed in CMake config files generated by Boost.Build (https://github.com/boostorg/boost_install/issues/18),
+// which makes it non-trivial for users to discover the libraries they need. This feature is deprecated and may be removed in the future,
+// when the situation with CMake config files improves.
+// Note that the library build system is the principal source of linking the library, which must work regardless of auto-linking.
+#include <boost/predef/platform.h>
+#include <boost/winapi/basic_types.hpp>
+
+#if defined(BOOST_FILESYSTEM_HAS_BCRYPT) // defined on the command line by the project
+#include <boost/winapi/error_codes.hpp>
+#include <boost/winapi/bcrypt.hpp>
+#if !defined(BOOST_FILESYSTEM_NO_DEPRECATED) && defined(_MSC_VER)
+#pragma comment(lib, "bcrypt.lib")
+#endif // !defined(BOOST_FILESYSTEM_NO_DEPRECATED) && defined(_MSC_VER)
+#else  // defined(BOOST_FILESYSTEM_HAS_BCRYPT)
+#include <boost/winapi/crypt.hpp>
+#include <boost/winapi/get_last_error.hpp>
+#if !defined(BOOST_FILESYSTEM_NO_DEPRECATED) && defined(_MSC_VER)
+#if !defined(_WIN32_WCE)
+#pragma comment(lib, "advapi32.lib")
+#else
+#pragma comment(lib, "coredll.lib")
+#endif
+#endif // !defined(BOOST_FILESYSTEM_NO_DEPRECATED) && defined(_MSC_VER)
+#endif // defined(BOOST_FILESYSTEM_HAS_BCRYPT)
+
+#endif // BOOST_POSIX_API
+
+#include <cstddef>
+#include <boost/filesystem/config.hpp>
+#include <boost/filesystem/operations.hpp>
+#include "private_config.hpp"
+#include "atomic_tools.hpp"
+#include "error_handling.hpp"
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+#if defined(BOOST_POSIX_API)
+// At least Mac OS X 10.6 and older doesn't support O_CLOEXEC
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#endif
+#endif // defined(BOOST_POSIX_API)
+
+namespace boost {
+namespace filesystem {
+namespace detail {
+
+namespace {
+
+#if defined(BOOST_POSIX_API) && !defined(BOOST_FILESYSTEM_HAS_ARC4RANDOM)
+
+//! Fills buffer with cryptographically random data obtained from /dev/(u)random
+int fill_random_dev_random(void* buf, std::size_t len)
+{
+    boost::scope::unique_fd file;
+    while (true)
+    {
+        file.reset(::open("/dev/urandom", O_RDONLY | O_CLOEXEC));
+        if (!file)
+        {
+            if (errno == EINTR)
+                continue;
+        }
+
+        break;
+    }
+
+    if (!file)
+    {
+        while (true)
+        {
+            file.reset(::open("/dev/random", O_RDONLY | O_CLOEXEC));
+            if (!file)
+            {
+                const int err = errno;
+                if (err == EINTR)
+                    continue;
+                return err;
+            }
+
+            break;
+        }
+    }
+
+    std::size_t bytes_read = 0u;
+    while (bytes_read < len)
+    {
+        ssize_t n = ::read(file.get(), buf, len - bytes_read);
+        if (BOOST_UNLIKELY(n < 0))
+        {
+            const int err = errno;
+            if (err == EINTR)
+                continue;
+            return err;
+        }
+
+        bytes_read += n;
+        buf = static_cast< char* >(buf) + n;
+    }
+
+    return 0;
+}
+
+#if defined(BOOST_FILESYSTEM_HAS_GETRANDOM) || defined(BOOST_FILESYSTEM_HAS_GETRANDOM_SYSCALL)
+
+typedef int fill_random_t(void* buf, std::size_t len);
+
+//! Pointer to the implementation of fill_random.
+fill_random_t* fill_random = &fill_random_dev_random;
+
+//! Fills buffer with cryptographically random data obtained from getrandom()
+int fill_random_getrandom(void* buf, std::size_t len)
+{
+    std::size_t bytes_read = 0u;
+    while (bytes_read < len)
+    {
+#if defined(BOOST_FILESYSTEM_HAS_GETRANDOM)
+        ssize_t n = ::getrandom(buf, len - bytes_read, 0u);
+#else
+        ssize_t n = ::syscall(SYS_getrandom, buf, len - bytes_read, 0u);
+#endif
+        if (BOOST_UNLIKELY(n < 0))
+        {
+            const int err = errno;
+            if (err == EINTR)
+                continue;
+
+            if (err == ENOSYS && bytes_read == 0u)
+            {
+                filesystem::detail::atomic_store_relaxed(fill_random, &fill_random_dev_random);
+                return fill_random_dev_random(buf, len);
+            }
+
+            return err;
+        }
+
+        bytes_read += n;
+        buf = static_cast< char* >(buf) + n;
+    }
+
+    return 0;
+}
+
+#endif // defined(BOOST_FILESYSTEM_HAS_GETRANDOM) || defined(BOOST_FILESYSTEM_HAS_GETRANDOM_SYSCALL)
+
+#endif // defined(BOOST_POSIX_API) && !defined(BOOST_FILESYSTEM_HAS_ARC4RANDOM)
+
+void system_crypt_random(void* buf, std::size_t len, boost::system::error_code* ec)
+{
+#if defined(BOOST_POSIX_API)
+
+#if defined(BOOST_FILESYSTEM_HAS_GETRANDOM) || defined(BOOST_FILESYSTEM_HAS_GETRANDOM_SYSCALL)
+
+    int err = filesystem::detail::atomic_load_relaxed(fill_random)(buf, len);
+    if (BOOST_UNLIKELY(err != 0))
+        emit_error(err, ec, "boost::filesystem::unique_path");
+
+#elif defined(BOOST_FILESYSTEM_HAS_ARC4RANDOM)
+
+    arc4random_buf(buf, len);
+
+#else
+
+    int err = fill_random_dev_random(buf, len);
+    if (BOOST_UNLIKELY(err != 0))
+        emit_error(err, ec, "boost::filesystem::unique_path");
+
+#endif
+
+#else // defined(BOOST_POSIX_API)
+
+#if defined(BOOST_FILESYSTEM_HAS_BCRYPT)
+
+    boost::winapi::BCRYPT_ALG_HANDLE_ handle;
+    boost::winapi::NTSTATUS_ status = boost::winapi::BCryptOpenAlgorithmProvider(&handle, boost::winapi::BCRYPT_RNG_ALGORITHM_, nullptr, 0);
+    if (BOOST_UNLIKELY(status != 0))
+    {
+    fail:
+        emit_error(translate_ntstatus(status), ec, "boost::filesystem::unique_path");
+        return;
+    }
+
+    status = boost::winapi::BCryptGenRandom(handle, static_cast< boost::winapi::PUCHAR_ >(buf), static_cast< boost::winapi::ULONG_ >(len), 0);
+
+    boost::winapi::BCryptCloseAlgorithmProvider(handle, 0);
+
+    if (BOOST_UNLIKELY(status != 0))
+        goto fail;
+
+#else // defined(BOOST_FILESYSTEM_HAS_BCRYPT)
+
+    boost::winapi::HCRYPTPROV_ handle;
+    boost::winapi::DWORD_ err = 0u;
+    if (BOOST_UNLIKELY(!boost::winapi::CryptAcquireContextW(&handle, nullptr, nullptr, boost::winapi::PROV_RSA_FULL_, boost::winapi::CRYPT_VERIFYCONTEXT_ | boost::winapi::CRYPT_SILENT_)))
+    {
+        err = boost::winapi::GetLastError();
+
+    fail:
+        emit_error(err, ec, "boost::filesystem::unique_path");
+        return;
+    }
+
+    boost::winapi::BOOL_ gen_ok = boost::winapi::CryptGenRandom(handle, static_cast< boost::winapi::DWORD_ >(len), static_cast< boost::winapi::BYTE_* >(buf));
+
+    if (BOOST_UNLIKELY(!gen_ok))
+        err = boost::winapi::GetLastError();
+
+    boost::winapi::CryptReleaseContext(handle, 0);
+
+    if (BOOST_UNLIKELY(!gen_ok))
+        goto fail;
+
+#endif // defined(BOOST_FILESYSTEM_HAS_BCRYPT)
+
+#endif // defined(BOOST_POSIX_API)
+}
+
+#ifdef BOOST_WINDOWS_API
+BOOST_CONSTEXPR_OR_CONST wchar_t hex[] = L"0123456789abcdef";
+BOOST_CONSTEXPR_OR_CONST wchar_t percent = L'%';
+#else
+BOOST_CONSTEXPR_OR_CONST char hex[] = "0123456789abcdef";
+BOOST_CONSTEXPR_OR_CONST char percent = '%';
+#endif
+
+} // unnamed namespace
+
+#if defined(linux) || defined(__linux) || defined(__linux__)
+
+//! Initializes fill_random implementation pointer
+void init_fill_random_impl(unsigned int major_ver, unsigned int minor_ver, unsigned int patch_ver)
+{
+#if defined(BOOST_FILESYSTEM_HAS_INIT_PRIORITY) && \
+    (defined(BOOST_FILESYSTEM_HAS_GETRANDOM) || defined(BOOST_FILESYSTEM_HAS_GETRANDOM_SYSCALL))
+    fill_random_t* fr = &fill_random_dev_random;
+
+    if (major_ver > 3u || (major_ver == 3u && minor_ver >= 17u))
+        fr = &fill_random_getrandom;
+
+    filesystem::detail::atomic_store_relaxed(fill_random, fr);
+#endif
+}
+
+#endif // defined(linux) || defined(__linux) || defined(__linux__)
+
+BOOST_FILESYSTEM_DECL
+path unique_path(path const& model, system::error_code* ec)
+{
+    // This function used wstring for fear of misidentifying
+    // a part of a multibyte character as a percent sign.
+    // However, double byte encodings only have 80-FF as lead
+    // bytes and 40-7F as trailing bytes, whereas % is 25.
+    // So, use string on POSIX and avoid conversions.
+
+    path::string_type s(model.native());
+
+    char ran[16] = {};                                                    // init to avoid clang static analyzer message
+                                                                          // see ticket #8954
+    BOOST_CONSTEXPR_OR_CONST unsigned int max_nibbles = 2u * sizeof(ran); // 4-bits per nibble
+
+    unsigned int nibbles_used = max_nibbles;
+    for (path::string_type::size_type i = 0, n = s.size(); i < n; ++i)
+    {
+        if (s[i] == percent) // digit request
+        {
+            if (nibbles_used == max_nibbles)
+            {
+                system_crypt_random(ran, sizeof(ran), ec);
+                if (ec && *ec)
+                    return path();
+                nibbles_used = 0;
+            }
+            unsigned int c = ran[nibbles_used / 2u];
+            c >>= 4u * (nibbles_used++ & 1u); // if odd, shift right 1 nibble
+            s[i] = hex[c & 0xf];              // convert to hex digit and replace
+        }
+    }
+
+    if (ec)
+        ec->clear();
+
+    return s;
+}
+
+} // namespace detail
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
diff --git a/contrib/restricted/boost/filesystem/src/utf8_codecvt_facet.cpp b/contrib/restricted/boost/filesystem/src/utf8_codecvt_facet.cpp
new file mode 100644
index 0000000000..7e5939bb71
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/utf8_codecvt_facet.cpp
@@ -0,0 +1,29 @@
+// Copyright Vladimir Prus 2004.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt
+// or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include "platform_config.hpp"
+
+#include <boost/filesystem/config.hpp>
+
+#include <boost/filesystem/detail/header.hpp>
+
+#define BOOST_UTF8_BEGIN_NAMESPACE \
+    namespace boost { \
+    namespace filesystem { \
+    namespace detail {
+
+#define BOOST_UTF8_END_NAMESPACE \
+    } \
+    } \
+    }
+#define BOOST_UTF8_DECL BOOST_FILESYSTEM_DECL
+
+#include <boost/detail/utf8_codecvt_facet.ipp>
+
+#undef BOOST_UTF8_BEGIN_NAMESPACE
+#undef BOOST_UTF8_END_NAMESPACE
+#undef BOOST_UTF8_DECL
+
+#include <boost/filesystem/detail/footer.hpp>
diff --git a/contrib/restricted/boost/filesystem/src/windows_file_codecvt.cpp b/contrib/restricted/boost/filesystem/src/windows_file_codecvt.cpp
new file mode 100644
index 0000000000..f86ba5111b
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/windows_file_codecvt.cpp
@@ -0,0 +1,72 @@
+//  filesystem windows_file_codecvt.cpp  -----------------------------------------//
+
+//  Copyright Beman Dawes 2009
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  Library home page: http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#include "platform_config.hpp"
+
+#include <cwchar> // for mbstate_t
+
+#ifdef BOOST_WINDOWS_API
+
+#include "windows_file_codecvt.hpp"
+
+#include <windows.h>
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+namespace boost {
+namespace filesystem {
+namespace detail {
+
+std::codecvt_base::result windows_file_codecvt::do_in(
+    std::mbstate_t&,
+    const char* from, const char* from_end, const char*& from_next,
+    wchar_t* to, wchar_t* to_end, wchar_t*& to_next) const
+{
+    UINT codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
+
+    int count;
+    if ((count = ::MultiByteToWideChar(codepage, MB_PRECOMPOSED, from, static_cast< int >(from_end - from), to, static_cast< int >(to_end - to))) == 0)
+    {
+        return error; // conversion failed
+    }
+
+    from_next = from_end;
+    to_next = to + count;
+    *to_next = L'\0';
+    return ok;
+}
+
+std::codecvt_base::result windows_file_codecvt::do_out(
+    std::mbstate_t&,
+    const wchar_t* from, const wchar_t* from_end, const wchar_t*& from_next,
+    char* to, char* to_end, char*& to_next) const
+{
+    UINT codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
+
+    int count;
+    if ((count = ::WideCharToMultiByte(codepage, WC_NO_BEST_FIT_CHARS, from, static_cast< int >(from_end - from), to, static_cast< int >(to_end - to), 0, 0)) == 0)
+    {
+        return error; // conversion failed
+    }
+
+    from_next = from_end;
+    to_next = to + count;
+    *to_next = '\0';
+    return ok;
+}
+
+} // namespace detail
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
+
+#endif // BOOST_WINDOWS_API
diff --git a/contrib/restricted/boost/filesystem/src/windows_file_codecvt.hpp b/contrib/restricted/boost/filesystem/src/windows_file_codecvt.hpp
new file mode 100644
index 0000000000..e0f0ae6c3a
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/windows_file_codecvt.hpp
@@ -0,0 +1,72 @@
+//  filesystem windows_file_codecvt.hpp  -----------------------------------------------//
+
+//  Copyright Beman Dawes 2009
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  Library home page: http://www.boost.org/libs/filesystem
+
+#ifndef BOOST_FILESYSTEM_WINDOWS_FILE_CODECVT_HPP
+#define BOOST_FILESYSTEM_WINDOWS_FILE_CODECVT_HPP
+
+#include <boost/filesystem/config.hpp>
+
+#ifdef BOOST_WINDOWS_API
+
+#include <boost/config/workaround.hpp>
+#include <cstddef>
+#include <cwchar> // std::mbstate_t
+#include <locale>
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+namespace boost {
+namespace filesystem {
+namespace detail {
+
+//------------------------------------------------------------------------------------//
+//                                                                                    //
+//                          class windows_file_codecvt                                //
+//                                                                                    //
+//  Warning: partial implementation; even do_in and do_out only partially meet the    //
+//  standard library specifications as the "to" buffer must hold the entire result.   //
+//                                                                                    //
+//------------------------------------------------------------------------------------//
+
+class BOOST_SYMBOL_VISIBLE windows_file_codecvt final :
+    public std::codecvt< wchar_t, char, std::mbstate_t >
+{
+public:
+    explicit windows_file_codecvt(std::size_t refs = 0) :
+        std::codecvt< wchar_t, char, std::mbstate_t >(refs)
+    {
+    }
+
+protected:
+    bool do_always_noconv() const noexcept override { return false; }
+
+    //  seems safest to assume variable number of characters since we don't
+    //  actually know what codepage is active
+    int do_encoding() const noexcept override { return 0; }
+    std::codecvt_base::result do_in(std::mbstate_t& state, const char* from, const char* from_end, const char*& from_next, wchar_t* to, wchar_t* to_end, wchar_t*& to_next) const override;
+    std::codecvt_base::result do_out(std::mbstate_t& state, const wchar_t* from, const wchar_t* from_end, const wchar_t*& from_next, char* to, char* to_end, char*& to_next) const override;
+    std::codecvt_base::result do_unshift(std::mbstate_t&, char* /*from*/, char* /*to*/, char*& /*next*/) const override { return ok; }
+    int do_length(std::mbstate_t&, const char* /*from*/, const char* /*from_end*/, std::size_t /*max*/) const
+#if BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600))
+        throw()
+#endif
+        override
+    { return 0; }
+    int do_max_length() const noexcept override { return 0; }
+};
+
+} // namespace detail
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
+
+#endif // BOOST_WINDOWS_API
+
+#endif // BOOST_FILESYSTEM_WINDOWS_FILE_CODECVT_HPP
diff --git a/contrib/restricted/boost/filesystem/src/windows_tools.hpp b/contrib/restricted/boost/filesystem/src/windows_tools.hpp
new file mode 100644
index 0000000000..c16b61fb48
--- /dev/null
+++ b/contrib/restricted/boost/filesystem/src/windows_tools.hpp
@@ -0,0 +1,310 @@
+//  windows_tools.hpp  -----------------------------------------------------------------//
+
+//  Copyright 2001 Dietmar Kuehl
+//  Copyright 2002-2009, 2014 Beman Dawes
+//  Copyright 2021-2022 Andrey Semashev
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  See library home page at http://www.boost.org/libs/filesystem
+
+//--------------------------------------------------------------------------------------//
+
+#ifndef BOOST_FILESYSTEM_SRC_WINDOWS_TOOLS_HPP_
+#define BOOST_FILESYSTEM_SRC_WINDOWS_TOOLS_HPP_
+
+#include <boost/filesystem/config.hpp>
+#include <boost/filesystem/path.hpp>
+#include <boost/filesystem/file_status.hpp>
+#include <boost/system/error_code.hpp>
+#include <boost/scope/unique_resource.hpp>
+#include <boost/winapi/basic_types.hpp> // NTSTATUS_
+
+#include <windows.h>
+
+#include <boost/filesystem/detail/header.hpp> // must be the last #include
+
+#ifndef IO_REPARSE_TAG_DEDUP
+#define IO_REPARSE_TAG_DEDUP (0x80000013L)
+#endif
+
+#ifndef IO_REPARSE_TAG_MOUNT_POINT
+#define IO_REPARSE_TAG_MOUNT_POINT (0xA0000003L)
+#endif
+
+#ifndef IO_REPARSE_TAG_SYMLINK
+#define IO_REPARSE_TAG_SYMLINK (0xA000000CL)
+#endif
+
+namespace boost {
+namespace filesystem {
+namespace detail {
+
+//! Deleter for HANDLEs
+struct handle_deleter
+{
+    using result_type = void;
+
+    result_type operator() (HANDLE h) const noexcept
+    {
+        ::CloseHandle(h);
+    }
+};
+
+//! Resource traits for HANDLEs
+struct handle_resource_traits
+{
+    static HANDLE make_default() noexcept
+    {
+        return INVALID_HANDLE_VALUE;
+    }
+
+    static bool is_allocated(HANDLE h) noexcept
+    {
+        return h != INVALID_HANDLE_VALUE && h != nullptr;
+    }
+};
+
+//! Unique HANDLE wrapper
+using unique_handle = boost::scope::unique_resource< HANDLE, handle_deleter, handle_resource_traits >;
+
+BOOST_INLINE_VARIABLE BOOST_CONSTEXPR_OR_CONST wchar_t colon = L':';
+BOOST_INLINE_VARIABLE BOOST_CONSTEXPR_OR_CONST wchar_t questionmark = L'?';
+
+inline bool is_letter(wchar_t c)
+{
+    return (c >= L'A' && c <= L'Z') || (c >= L'a' && c <= L'z');
+}
+
+inline bool equal_extension(wchar_t const* p, wchar_t const (&x1)[5], wchar_t const (&x2)[5])
+{
+    return (p[0] == x1[0] || p[0] == x2[0]) &&
+        (p[1] == x1[1] || p[1] == x2[1]) &&
+        (p[2] == x1[2] || p[2] == x2[2]) &&
+        (p[3] == x1[3] || p[3] == x2[3]) &&
+        p[4] == 0;
+}
+
+inline boost::filesystem::perms make_permissions(boost::filesystem::path const& p, DWORD attr)
+{
+    boost::filesystem::perms prms = boost::filesystem::owner_read | boost::filesystem::group_read | boost::filesystem::others_read;
+    if ((attr & FILE_ATTRIBUTE_READONLY) == 0u)
+        prms |= boost::filesystem::owner_write | boost::filesystem::group_write | boost::filesystem::others_write;
+    boost::filesystem::path ext = detail::path_algorithms::extension_v4(p);
+    wchar_t const* q = ext.c_str();
+    if (equal_extension(q, L".exe", L".EXE") || equal_extension(q, L".com", L".COM") || equal_extension(q, L".bat", L".BAT") || equal_extension(q, L".cmd", L".CMD"))
+        prms |= boost::filesystem::owner_exe | boost::filesystem::group_exe | boost::filesystem::others_exe;
+    return prms;
+}
+
+ULONG get_reparse_point_tag_ioctl(HANDLE h, boost::filesystem::path const& p, boost::system::error_code* ec);
+
+inline bool is_reparse_point_tag_a_symlink(ULONG reparse_point_tag)
+{
+    return reparse_point_tag == IO_REPARSE_TAG_SYMLINK
+        // Issue 9016 asked that NTFS directory junctions be recognized as directories.
+        // That is equivalent to recognizing them as symlinks, and then the normal symlink
+        // mechanism will take care of recognizing them as directories.
+        //
+        // Directory junctions are very similar to symlinks, but have some performance
+        // and other advantages over symlinks. They can be created from the command line
+        // with "mklink /J junction-name target-path".
+        //
+        // Note that mounted filesystems also have the same repartse point tag, which makes
+        // them look like directory symlinks in terms of Boost.Filesystem. read_symlink()
+        // may return a volume path or NT path for such symlinks.
+        || reparse_point_tag == IO_REPARSE_TAG_MOUNT_POINT; // aka "directory junction" or "junction"
+}
+
+//! Platform-specific parameters for directory iterator construction
+struct directory_iterator_params
+{
+    //! Handle of the directory to iterate over. If not \c INVALID_HANDLE_VALUE, the directory path is only used to generate paths returned by the iterator.
+    HANDLE dir_handle;
+    /*!
+     * If \c dir_handle is not \c INVALID_HANDLE_VALUE, specifies whether the directory iterator should close the handle upon destruction.
+     * If \c false, the handle must remain valid for the lifetime of the iterator.
+     */
+    bool close_handle;
+};
+
+//! IO_STATUS_BLOCK definition from Windows SDK.
+struct io_status_block
+{
+    union
+    {
+        boost::winapi::NTSTATUS_ Status;
+        PVOID Pointer;
+    };
+    ULONG_PTR Information;
+};
+
+//! UNICODE_STRING definition from Windows SDK
+struct unicode_string
+{
+    USHORT Length;
+    USHORT MaximumLength;
+    PWSTR Buffer;
+};
+
+//! OBJECT_ATTRIBUTES definition from Windows SDK
+struct object_attributes
+{
+    ULONG Length;
+    HANDLE RootDirectory;
+    unicode_string* ObjectName;
+    ULONG Attributes;
+    PVOID SecurityDescriptor;
+    PVOID SecurityQualityOfService;
+};
+
+#ifndef OBJ_CASE_INSENSITIVE
+#define OBJ_CASE_INSENSITIVE 0x00000040
+#endif
+#ifndef OBJ_DONT_REPARSE
+#define OBJ_DONT_REPARSE 0x00001000
+#endif
+
+#ifndef FILE_SUPERSEDE
+#define FILE_SUPERSEDE 0x00000000
+#endif
+#ifndef FILE_OPEN
+#define FILE_OPEN 0x00000001
+#endif
+#ifndef FILE_CREATE
+#define FILE_CREATE 0x00000002
+#endif
+#ifndef FILE_OPEN_IF
+#define FILE_OPEN_IF 0x00000003
+#endif
+#ifndef FILE_OVERWRITE
+#define FILE_OVERWRITE 0x00000004
+#endif
+#ifndef FILE_OVERWRITE_IF
+#define FILE_OVERWRITE_IF 0x00000005
+#endif
+
+#ifndef FILE_DIRECTORY_FILE
+#define FILE_DIRECTORY_FILE 0x00000001
+#endif
+#ifndef FILE_SYNCHRONOUS_IO_NONALERT
+#define FILE_SYNCHRONOUS_IO_NONALERT 0x00000020
+#endif
+#ifndef FILE_OPEN_FOR_BACKUP_INTENT
+#define FILE_OPEN_FOR_BACKUP_INTENT 0x00004000
+#endif
+#ifndef FILE_OPEN_REPARSE_POINT
+#define FILE_OPEN_REPARSE_POINT 0x00200000
+#endif
+
+//! NtCreateFile signature. Available since Windows 2000 (probably).
+typedef boost::winapi::NTSTATUS_ (NTAPI NtCreateFile_t)(
+    /*out*/ PHANDLE FileHandle,
+    /*in*/ ACCESS_MASK DesiredAccess,
+    /*in*/ object_attributes* ObjectAttributes,
+    /*out*/ io_status_block* IoStatusBlock,
+    /*in, optional*/ PLARGE_INTEGER AllocationSize,
+    /*in*/ ULONG FileAttributes,
+    /*in*/ ULONG ShareAccess,
+    /*in*/ ULONG CreateDisposition,
+    /*in*/ ULONG CreateOptions,
+    /*in, optional*/ PVOID EaBuffer,
+    /*in*/ ULONG EaLength);
+
+extern NtCreateFile_t* nt_create_file_api;
+
+//! PIO_APC_ROUTINE definition from Windows SDK
+typedef VOID (NTAPI* pio_apc_routine) (PVOID ApcContext, io_status_block* IoStatusBlock, ULONG Reserved);
+
+//! FILE_INFORMATION_CLASS enum entries
+enum file_information_class
+{
+    file_directory_information_class = 1
+};
+
+//! NtQueryDirectoryFile signature. Available since Windows NT 4.0 (probably).
+typedef boost::winapi::NTSTATUS_ (NTAPI NtQueryDirectoryFile_t)(
+    /*in*/ HANDLE FileHandle,
+    /*in, optional*/ HANDLE Event,
+    /*in, optional*/ pio_apc_routine ApcRoutine,
+    /*in, optional*/ PVOID ApcContext,
+    /*out*/ io_status_block* IoStatusBlock,
+    /*out*/ PVOID FileInformation,
+    /*in*/ ULONG Length,
+    /*in*/ file_information_class FileInformationClass,
+    /*in*/ BOOLEAN ReturnSingleEntry,
+    /*in, optional*/ unicode_string* FileName,
+    /*in*/ BOOLEAN RestartScan);
+
+extern NtQueryDirectoryFile_t* nt_query_directory_file_api;
+
+//! FILE_INFO_BY_HANDLE_CLASS enum entries
+enum file_info_by_handle_class
+{
+    file_basic_info_class = 0,
+    file_disposition_info_class = 4,
+    file_attribute_tag_info_class = 9,
+    file_id_both_directory_info_class = 10,
+    file_id_both_directory_restart_info_class = 11,
+    file_full_directory_info_class = 14,
+    file_full_directory_restart_info_class = 15,
+    file_id_extd_directory_info_class = 19,
+    file_id_extd_directory_restart_info_class = 20,
+    file_disposition_info_ex_class = 21
+};
+
+//! FILE_ATTRIBUTE_TAG_INFO definition from Windows SDK
+struct file_attribute_tag_info
+{
+    DWORD FileAttributes;
+    DWORD ReparseTag;
+};
+
+//! GetFileInformationByHandleEx signature. Available since Windows Vista.
+typedef BOOL (WINAPI GetFileInformationByHandleEx_t)(
+    /*__in*/  HANDLE hFile,
+    /*__in*/  file_info_by_handle_class FileInformationClass, // the actual type is FILE_INFO_BY_HANDLE_CLASS enum
+    /*__out_bcount(dwBufferSize)*/ LPVOID lpFileInformation,
+    /*__in*/  DWORD dwBufferSize);
+
+extern GetFileInformationByHandleEx_t* get_file_information_by_handle_ex_api;
+
+//! Creates a file handle
+inline unique_handle create_file_handle
+(
+    boost::filesystem::path const& p,
+    DWORD dwDesiredAccess,
+    DWORD dwShareMode,
+    LPSECURITY_ATTRIBUTES lpSecurityAttributes,
+    DWORD dwCreationDisposition,
+    DWORD dwFlagsAndAttributes,
+    HANDLE hTemplateFile = nullptr
+)
+{
+    return unique_handle(::CreateFileW(p.c_str(), dwDesiredAccess, dwShareMode, lpSecurityAttributes, dwCreationDisposition, dwFlagsAndAttributes, hTemplateFile));
+}
+
+//! Creates a file handle for a file relative to a previously opened base directory. The file path must be relative and in preferred format.
+boost::winapi::NTSTATUS_ nt_create_file_handle_at
+(
+    unique_handle& out,
+    HANDLE basedir_handle,
+    boost::filesystem::path const& p,
+    ULONG FileAttributes,
+    ACCESS_MASK DesiredAccess,
+    ULONG ShareMode,
+    ULONG CreateDisposition,
+    ULONG CreateOptions
+);
+
+//! Returns status of the file identified by an open handle. The path \a p is used to report errors and infer file permissions.
+filesystem::file_status status_by_handle(HANDLE h, path const& p, system::error_code* ec);
+
+} // namespace detail
+} // namespace filesystem
+} // namespace boost
+
+#include <boost/filesystem/detail/footer.hpp>
+
+#endif // BOOST_FILESYSTEM_SRC_WINDOWS_TOOLS_HPP_