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//
// SharedMemoryImpl.h
//
// Library: Foundation
// Package: Processes
// Module: SharedMemoryImpl
//
// Definition of the SharedMemoryImpl class.
//
// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_SharedMemoryImpl_INCLUDED
#define Foundation_SharedMemoryImpl_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/SharedMemory.h"
#include "Poco/RefCountedObject.h"
namespace Poco {
class Foundation_API SharedMemoryImpl: public RefCountedObject
/// Shared memory implementation for POSIX platforms.
{
public:
SharedMemoryImpl(const std::string& name, std::size_t size, SharedMemory::AccessMode mode, const void* addrHint, bool server);
/// Creates or connects to a shared memory object with the given name.
///
/// For maximum portability, name should be a valid Unix filename and not
/// contain any slashes or backslashes.
///
/// An address hint can be passed to the system, specifying the desired
/// start address of the shared memory area. Whether the hint
/// is actually honored is, however, up to the system. Windows platform
/// will generally ignore the hint.
///
/// If server is set to false, the shared memory region will be unlinked
/// by calling shm_unlink when the SharedMemory object is destroyed.
SharedMemoryImpl(const Poco::File& file, SharedMemory::AccessMode mode, const void* addrHint);
/// Maps the entire contents of file into a shared memory segment.
///
/// An address hint can be passed to the system, specifying the desired
/// start address of the shared memory area. Whether the hint
/// is actually honored is, however, up to the system. Windows platform
/// will generally ignore the hint.
char* begin() const;
/// Returns the start address of the shared memory segment.
char* end() const;
/// Returns the one-past-end end address of the shared memory segment.
protected:
void map(const void* addrHint);
/// Maps the shared memory object.
void unmap();
/// Unmaps the shared memory object.
void close();
/// Releases the handle for the shared memory segment.
~SharedMemoryImpl();
/// Destroys the SharedMemoryImpl.
private:
SharedMemoryImpl();
SharedMemoryImpl(const SharedMemoryImpl&);
SharedMemoryImpl& operator = (const SharedMemoryImpl&);
std::size_t _size;
int _fd;
char* _address;
SharedMemory::AccessMode _access;
std::string _name;
bool _fileMapped;
bool _server;
};
//
// inlines
//
inline char* SharedMemoryImpl::begin() const
{
return _address;
}
inline char* SharedMemoryImpl::end() const
{
return _address + _size;
}
} // namespace Poco
#endif // Foundation_SharedMemoryImpl_INCLUDED
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