intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 1634 insertions, 0 deletions

diff --git a/contrib/tools/python3/src/Modules/_threadmodule.c b/contrib/tools/python3/src/Modules/_threadmodule.c
new file mode 100644
index 0000000000..a370352238
--- /dev/null
+++ b/contrib/tools/python3/src/Modules/_threadmodule.c
@@ -0,0 +1,1634 @@
+
+/* Thread module */
+/* Interface to Sjoerd's portable C thread library */
+
+#include "Python.h"
+#include "pycore_pylifecycle.h"
+#include "pycore_interp.h"        // _PyInterpreterState.num_threads
+#include "pycore_pystate.h"       // _PyThreadState_Init()
+#include <stddef.h>               // offsetof()
+
+static PyObject *ThreadError;
+static PyObject *str_dict;
+
+_Py_IDENTIFIER(stderr);
+_Py_IDENTIFIER(flush);
+
+/* Lock objects */
+
+typedef struct {
+    PyObject_HEAD
+    PyThread_type_lock lock_lock;
+    PyObject *in_weakreflist;
+    char locked; /* for sanity checking */
+} lockobject;
+
+static void
+lock_dealloc(lockobject *self)
+{
+    if (self->in_weakreflist != NULL)
+        PyObject_ClearWeakRefs((PyObject *) self);
+    if (self->lock_lock != NULL) {
+        /* Unlock the lock so it's safe to free it */
+        if (self->locked)
+            PyThread_release_lock(self->lock_lock);
+        PyThread_free_lock(self->lock_lock);
+    }
+    PyObject_Del(self);
+}
+
+/* Helper to acquire an interruptible lock with a timeout.  If the lock acquire
+ * is interrupted, signal handlers are run, and if they raise an exception,
+ * PY_LOCK_INTR is returned.  Otherwise, PY_LOCK_ACQUIRED or PY_LOCK_FAILURE
+ * are returned, depending on whether the lock can be acquired within the
+ * timeout.
+ */
+static PyLockStatus
+acquire_timed(PyThread_type_lock lock, _PyTime_t timeout)
+{
+    PyLockStatus r;
+    _PyTime_t endtime = 0;
+    _PyTime_t microseconds;
+
+    if (timeout > 0)
+        endtime = _PyTime_GetMonotonicClock() + timeout;
+
+    do {
+        microseconds = _PyTime_AsMicroseconds(timeout, _PyTime_ROUND_CEILING);
+
+        /* first a simple non-blocking try without releasing the GIL */
+        r = PyThread_acquire_lock_timed(lock, 0, 0);
+        if (r == PY_LOCK_FAILURE && microseconds != 0) {
+            Py_BEGIN_ALLOW_THREADS
+            r = PyThread_acquire_lock_timed(lock, microseconds, 1);
+            Py_END_ALLOW_THREADS
+        }
+
+        if (r == PY_LOCK_INTR) {
+            /* Run signal handlers if we were interrupted.  Propagate
+             * exceptions from signal handlers, such as KeyboardInterrupt, by
+             * passing up PY_LOCK_INTR.  */
+            if (Py_MakePendingCalls() < 0) {
+                return PY_LOCK_INTR;
+            }
+
+            /* If we're using a timeout, recompute the timeout after processing
+             * signals, since those can take time.  */
+            if (timeout > 0) {
+                timeout = endtime - _PyTime_GetMonotonicClock();
+
+                /* Check for negative values, since those mean block forever.
+                 */
+                if (timeout < 0) {
+                    r = PY_LOCK_FAILURE;
+                }
+            }
+        }
+    } while (r == PY_LOCK_INTR);  /* Retry if we were interrupted. */
+
+    return r;
+}
+
+static int
+lock_acquire_parse_args(PyObject *args, PyObject *kwds,
+                        _PyTime_t *timeout)
+{
+    char *kwlist[] = {"blocking", "timeout", NULL};
+    int blocking = 1;
+    PyObject *timeout_obj = NULL;
+    const _PyTime_t unset_timeout = _PyTime_FromSeconds(-1);
+
+    *timeout = unset_timeout ;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|iO:acquire", kwlist,
+                                     &blocking, &timeout_obj))
+        return -1;
+
+    if (timeout_obj
+        && _PyTime_FromSecondsObject(timeout,
+                                     timeout_obj, _PyTime_ROUND_TIMEOUT) < 0)
+        return -1;
+
+    if (!blocking && *timeout != unset_timeout ) {
+        PyErr_SetString(PyExc_ValueError,
+                        "can't specify a timeout for a non-blocking call");
+        return -1;
+    }
+    if (*timeout < 0 && *timeout != unset_timeout) {
+        PyErr_SetString(PyExc_ValueError,
+                        "timeout value must be positive");
+        return -1;
+    }
+    if (!blocking)
+        *timeout = 0;
+    else if (*timeout != unset_timeout) {
+        _PyTime_t microseconds;
+
+        microseconds = _PyTime_AsMicroseconds(*timeout, _PyTime_ROUND_TIMEOUT);
+        if (microseconds >= PY_TIMEOUT_MAX) {
+            PyErr_SetString(PyExc_OverflowError,
+                            "timeout value is too large");
+            return -1;
+        }
+    }
+    return 0;
+}
+
+static PyObject *
+lock_PyThread_acquire_lock(lockobject *self, PyObject *args, PyObject *kwds)
+{
+    _PyTime_t timeout;
+    PyLockStatus r;
+
+    if (lock_acquire_parse_args(args, kwds, &timeout) < 0)
+        return NULL;
+
+    r = acquire_timed(self->lock_lock, timeout);
+    if (r == PY_LOCK_INTR) {
+        return NULL;
+    }
+
+    if (r == PY_LOCK_ACQUIRED)
+        self->locked = 1;
+    return PyBool_FromLong(r == PY_LOCK_ACQUIRED);
+}
+
+PyDoc_STRVAR(acquire_doc,
+"acquire(blocking=True, timeout=-1) -> bool\n\
+(acquire_lock() is an obsolete synonym)\n\
+\n\
+Lock the lock.  Without argument, this blocks if the lock is already\n\
+locked (even by the same thread), waiting for another thread to release\n\
+the lock, and return True once the lock is acquired.\n\
+With an argument, this will only block if the argument is true,\n\
+and the return value reflects whether the lock is acquired.\n\
+The blocking operation is interruptible.");
+
+static PyObject *
+lock_PyThread_release_lock(lockobject *self, PyObject *Py_UNUSED(ignored))
+{
+    /* Sanity check: the lock must be locked */
+    if (!self->locked) {
+        PyErr_SetString(ThreadError, "release unlocked lock");
+        return NULL;
+    }
+
+    PyThread_release_lock(self->lock_lock);
+    self->locked = 0;
+    Py_RETURN_NONE;
+}
+
+PyDoc_STRVAR(release_doc,
+"release()\n\
+(release_lock() is an obsolete synonym)\n\
+\n\
+Release the lock, allowing another thread that is blocked waiting for\n\
+the lock to acquire the lock.  The lock must be in the locked state,\n\
+but it needn't be locked by the same thread that unlocks it.");
+
+static PyObject *
+lock_locked_lock(lockobject *self, PyObject *Py_UNUSED(ignored))
+{
+    return PyBool_FromLong((long)self->locked);
+}
+
+PyDoc_STRVAR(locked_doc,
+"locked() -> bool\n\
+(locked_lock() is an obsolete synonym)\n\
+\n\
+Return whether the lock is in the locked state.");
+
+static PyObject *
+lock_repr(lockobject *self)
+{
+    return PyUnicode_FromFormat("<%s %s object at %p>",
+        self->locked ? "locked" : "unlocked", Py_TYPE(self)->tp_name, self);
+}
+
+#ifdef HAVE_FORK
+static PyObject *
+lock__at_fork_reinit(lockobject *self, PyObject *Py_UNUSED(args))
+{
+    if (_PyThread_at_fork_reinit(&self->lock_lock) < 0) {
+        PyErr_SetString(ThreadError, "failed to reinitialize lock at fork");
+        return NULL;
+    }
+
+    self->locked = 0;
+
+    Py_RETURN_NONE;
+}
+#endif  /* HAVE_FORK */
+
+
+static PyMethodDef lock_methods[] = {
+    {"acquire_lock", (PyCFunction)(void(*)(void))lock_PyThread_acquire_lock,
+     METH_VARARGS | METH_KEYWORDS, acquire_doc},
+    {"acquire",      (PyCFunction)(void(*)(void))lock_PyThread_acquire_lock,
+     METH_VARARGS | METH_KEYWORDS, acquire_doc},
+    {"release_lock", (PyCFunction)lock_PyThread_release_lock,
+     METH_NOARGS, release_doc},
+    {"release",      (PyCFunction)lock_PyThread_release_lock,
+     METH_NOARGS, release_doc},
+    {"locked_lock",  (PyCFunction)lock_locked_lock,
+     METH_NOARGS, locked_doc},
+    {"locked",       (PyCFunction)lock_locked_lock,
+     METH_NOARGS, locked_doc},
+    {"__enter__",    (PyCFunction)(void(*)(void))lock_PyThread_acquire_lock,
+     METH_VARARGS | METH_KEYWORDS, acquire_doc},
+    {"__exit__",    (PyCFunction)lock_PyThread_release_lock,
+     METH_VARARGS, release_doc},
+#ifdef HAVE_FORK
+    {"_at_fork_reinit",    (PyCFunction)lock__at_fork_reinit,
+     METH_NOARGS, NULL},
+#endif
+    {NULL,           NULL}              /* sentinel */
+};
+
+static PyTypeObject Locktype = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)
+    "_thread.lock",                     /*tp_name*/
+    sizeof(lockobject),                 /*tp_basicsize*/
+    0,                                  /*tp_itemsize*/
+    /* methods */
+    (destructor)lock_dealloc,           /*tp_dealloc*/
+    0,                                  /*tp_vectorcall_offset*/
+    0,                                  /*tp_getattr*/
+    0,                                  /*tp_setattr*/
+    0,                                  /*tp_as_async*/
+    (reprfunc)lock_repr,                /*tp_repr*/
+    0,                                  /*tp_as_number*/
+    0,                                  /*tp_as_sequence*/
+    0,                                  /*tp_as_mapping*/
+    0,                                  /*tp_hash*/
+    0,                                  /*tp_call*/
+    0,                                  /*tp_str*/
+    0,                                  /*tp_getattro*/
+    0,                                  /*tp_setattro*/
+    0,                                  /*tp_as_buffer*/
+    Py_TPFLAGS_DEFAULT,                 /*tp_flags*/
+    0,                                  /*tp_doc*/
+    0,                                  /*tp_traverse*/
+    0,                                  /*tp_clear*/
+    0,                                  /*tp_richcompare*/
+    offsetof(lockobject, in_weakreflist), /*tp_weaklistoffset*/
+    0,                                  /*tp_iter*/
+    0,                                  /*tp_iternext*/
+    lock_methods,                       /*tp_methods*/
+};
+
+/* Recursive lock objects */
+
+typedef struct {
+    PyObject_HEAD
+    PyThread_type_lock rlock_lock;
+    unsigned long rlock_owner;
+    unsigned long rlock_count;
+    PyObject *in_weakreflist;
+} rlockobject;
+
+static void
+rlock_dealloc(rlockobject *self)
+{
+    if (self->in_weakreflist != NULL)
+        PyObject_ClearWeakRefs((PyObject *) self);
+    /* self->rlock_lock can be NULL if PyThread_allocate_lock() failed
+       in rlock_new() */
+    if (self->rlock_lock != NULL) {
+        /* Unlock the lock so it's safe to free it */
+        if (self->rlock_count > 0)
+            PyThread_release_lock(self->rlock_lock);
+
+        PyThread_free_lock(self->rlock_lock);
+    }
+    Py_TYPE(self)->tp_free(self);
+}
+
+static PyObject *
+rlock_acquire(rlockobject *self, PyObject *args, PyObject *kwds)
+{
+    _PyTime_t timeout;
+    unsigned long tid;
+    PyLockStatus r = PY_LOCK_ACQUIRED;
+
+    if (lock_acquire_parse_args(args, kwds, &timeout) < 0)
+        return NULL;
+
+    tid = PyThread_get_thread_ident();
+    if (self->rlock_count > 0 && tid == self->rlock_owner) {
+        unsigned long count = self->rlock_count + 1;
+        if (count <= self->rlock_count) {
+            PyErr_SetString(PyExc_OverflowError,
+                            "Internal lock count overflowed");
+            return NULL;
+        }
+        self->rlock_count = count;
+        Py_RETURN_TRUE;
+    }
+    r = acquire_timed(self->rlock_lock, timeout);
+    if (r == PY_LOCK_ACQUIRED) {
+        assert(self->rlock_count == 0);
+        self->rlock_owner = tid;
+        self->rlock_count = 1;
+    }
+    else if (r == PY_LOCK_INTR) {
+        return NULL;
+    }
+
+    return PyBool_FromLong(r == PY_LOCK_ACQUIRED);
+}
+
+PyDoc_STRVAR(rlock_acquire_doc,
+"acquire(blocking=True) -> bool\n\
+\n\
+Lock the lock.  `blocking` indicates whether we should wait\n\
+for the lock to be available or not.  If `blocking` is False\n\
+and another thread holds the lock, the method will return False\n\
+immediately.  If `blocking` is True and another thread holds\n\
+the lock, the method will wait for the lock to be released,\n\
+take it and then return True.\n\
+(note: the blocking operation is interruptible.)\n\
+\n\
+In all other cases, the method will return True immediately.\n\
+Precisely, if the current thread already holds the lock, its\n\
+internal counter is simply incremented. If nobody holds the lock,\n\
+the lock is taken and its internal counter initialized to 1.");
+
+static PyObject *
+rlock_release(rlockobject *self, PyObject *Py_UNUSED(ignored))
+{
+    unsigned long tid = PyThread_get_thread_ident();
+
+    if (self->rlock_count == 0 || self->rlock_owner != tid) {
+        PyErr_SetString(PyExc_RuntimeError,
+                        "cannot release un-acquired lock");
+        return NULL;
+    }
+    if (--self->rlock_count == 0) {
+        self->rlock_owner = 0;
+        PyThread_release_lock(self->rlock_lock);
+    }
+    Py_RETURN_NONE;
+}
+
+PyDoc_STRVAR(rlock_release_doc,
+"release()\n\
+\n\
+Release the lock, allowing another thread that is blocked waiting for\n\
+the lock to acquire the lock.  The lock must be in the locked state,\n\
+and must be locked by the same thread that unlocks it; otherwise a\n\
+`RuntimeError` is raised.\n\
+\n\
+Do note that if the lock was acquire()d several times in a row by the\n\
+current thread, release() needs to be called as many times for the lock\n\
+to be available for other threads.");
+
+static PyObject *
+rlock_acquire_restore(rlockobject *self, PyObject *args)
+{
+    unsigned long owner;
+    unsigned long count;
+    int r = 1;
+
+    if (!PyArg_ParseTuple(args, "(kk):_acquire_restore", &count, &owner))
+        return NULL;
+
+    if (!PyThread_acquire_lock(self->rlock_lock, 0)) {
+        Py_BEGIN_ALLOW_THREADS
+        r = PyThread_acquire_lock(self->rlock_lock, 1);
+        Py_END_ALLOW_THREADS
+    }
+    if (!r) {
+        PyErr_SetString(ThreadError, "couldn't acquire lock");
+        return NULL;
+    }
+    assert(self->rlock_count == 0);
+    self->rlock_owner = owner;
+    self->rlock_count = count;
+    Py_RETURN_NONE;
+}
+
+PyDoc_STRVAR(rlock_acquire_restore_doc,
+"_acquire_restore(state) -> None\n\
+\n\
+For internal use by `threading.Condition`.");
+
+static PyObject *
+rlock_release_save(rlockobject *self, PyObject *Py_UNUSED(ignored))
+{
+    unsigned long owner;
+    unsigned long count;
+
+    if (self->rlock_count == 0) {
+        PyErr_SetString(PyExc_RuntimeError,
+                        "cannot release un-acquired lock");
+        return NULL;
+    }
+
+    owner = self->rlock_owner;
+    count = self->rlock_count;
+    self->rlock_count = 0;
+    self->rlock_owner = 0;
+    PyThread_release_lock(self->rlock_lock);
+    return Py_BuildValue("kk", count, owner);
+}
+
+PyDoc_STRVAR(rlock_release_save_doc,
+"_release_save() -> tuple\n\
+\n\
+For internal use by `threading.Condition`.");
+
+
+static PyObject *
+rlock_is_owned(rlockobject *self, PyObject *Py_UNUSED(ignored))
+{
+    unsigned long tid = PyThread_get_thread_ident();
+
+    if (self->rlock_count > 0 && self->rlock_owner == tid) {
+        Py_RETURN_TRUE;
+    }
+    Py_RETURN_FALSE;
+}
+
+PyDoc_STRVAR(rlock_is_owned_doc,
+"_is_owned() -> bool\n\
+\n\
+For internal use by `threading.Condition`.");
+
+static PyObject *
+rlock_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+    rlockobject *self = (rlockobject *) type->tp_alloc(type, 0);
+    if (self == NULL) {
+        return NULL;
+    }
+    self->in_weakreflist = NULL;
+    self->rlock_owner = 0;
+    self->rlock_count = 0;
+
+    self->rlock_lock = PyThread_allocate_lock();
+    if (self->rlock_lock == NULL) {
+        Py_DECREF(self);
+        PyErr_SetString(ThreadError, "can't allocate lock");
+        return NULL;
+    }
+    return (PyObject *) self;
+}
+
+static PyObject *
+rlock_repr(rlockobject *self)
+{
+    return PyUnicode_FromFormat("<%s %s object owner=%ld count=%lu at %p>",
+        self->rlock_count ? "locked" : "unlocked",
+        Py_TYPE(self)->tp_name, self->rlock_owner,
+        self->rlock_count, self);
+}
+
+
+#ifdef HAVE_FORK
+static PyObject *
+rlock__at_fork_reinit(rlockobject *self, PyObject *Py_UNUSED(args))
+{
+    if (_PyThread_at_fork_reinit(&self->rlock_lock) < 0) {
+        PyErr_SetString(ThreadError, "failed to reinitialize lock at fork");
+        return NULL;
+    }
+
+    self->rlock_owner = 0;
+    self->rlock_count = 0;
+
+    Py_RETURN_NONE;
+}
+#endif  /* HAVE_FORK */
+
+
+static PyMethodDef rlock_methods[] = {
+    {"acquire",      (PyCFunction)(void(*)(void))rlock_acquire,
+     METH_VARARGS | METH_KEYWORDS, rlock_acquire_doc},
+    {"release",      (PyCFunction)rlock_release,
+     METH_NOARGS, rlock_release_doc},
+    {"_is_owned",     (PyCFunction)rlock_is_owned,
+     METH_NOARGS, rlock_is_owned_doc},
+    {"_acquire_restore", (PyCFunction)rlock_acquire_restore,
+     METH_VARARGS, rlock_acquire_restore_doc},
+    {"_release_save", (PyCFunction)rlock_release_save,
+     METH_NOARGS, rlock_release_save_doc},
+    {"__enter__",    (PyCFunction)(void(*)(void))rlock_acquire,
+     METH_VARARGS | METH_KEYWORDS, rlock_acquire_doc},
+    {"__exit__",    (PyCFunction)rlock_release,
+     METH_VARARGS, rlock_release_doc},
+#ifdef HAVE_FORK
+    {"_at_fork_reinit",    (PyCFunction)rlock__at_fork_reinit,
+     METH_NOARGS, NULL},
+#endif
+    {NULL,           NULL}              /* sentinel */
+};
+
+
+static PyTypeObject RLocktype = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)
+    "_thread.RLock",                    /*tp_name*/
+    sizeof(rlockobject),                /*tp_basicsize*/
+    0,                                  /*tp_itemsize*/
+    /* methods */
+    (destructor)rlock_dealloc,          /*tp_dealloc*/
+    0,                                  /*tp_vectorcall_offset*/
+    0,                                  /*tp_getattr*/
+    0,                                  /*tp_setattr*/
+    0,                                  /*tp_as_async*/
+    (reprfunc)rlock_repr,               /*tp_repr*/
+    0,                                  /*tp_as_number*/
+    0,                                  /*tp_as_sequence*/
+    0,                                  /*tp_as_mapping*/
+    0,                                  /*tp_hash*/
+    0,                                  /*tp_call*/
+    0,                                  /*tp_str*/
+    0,                                  /*tp_getattro*/
+    0,                                  /*tp_setattro*/
+    0,                                  /*tp_as_buffer*/
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+    0,                                  /*tp_doc*/
+    0,                                  /*tp_traverse*/
+    0,                                  /*tp_clear*/
+    0,                                  /*tp_richcompare*/
+    offsetof(rlockobject, in_weakreflist), /*tp_weaklistoffset*/
+    0,                                  /*tp_iter*/
+    0,                                  /*tp_iternext*/
+    rlock_methods,                      /*tp_methods*/
+    0,                                  /* tp_members */
+    0,                                  /* tp_getset */
+    0,                                  /* tp_base */
+    0,                                  /* tp_dict */
+    0,                                  /* tp_descr_get */
+    0,                                  /* tp_descr_set */
+    0,                                  /* tp_dictoffset */
+    0,                                  /* tp_init */
+    PyType_GenericAlloc,                /* tp_alloc */
+    rlock_new                           /* tp_new */
+};
+
+static lockobject *
+newlockobject(void)
+{
+    lockobject *self;
+    self = PyObject_New(lockobject, &Locktype);
+    if (self == NULL)
+        return NULL;
+    self->lock_lock = PyThread_allocate_lock();
+    self->locked = 0;
+    self->in_weakreflist = NULL;
+    if (self->lock_lock == NULL) {
+        Py_DECREF(self);
+        PyErr_SetString(ThreadError, "can't allocate lock");
+        return NULL;
+    }
+    return self;
+}
+
+/* Thread-local objects */
+
+/* Quick overview:
+
+   We need to be able to reclaim reference cycles as soon as possible
+   (both when a thread is being terminated, or a thread-local object
+    becomes unreachable from user data).  Constraints:
+   - it must not be possible for thread-state dicts to be involved in
+     reference cycles (otherwise the cyclic GC will refuse to consider
+     objects referenced from a reachable thread-state dict, even though
+     local_dealloc would clear them)
+   - the death of a thread-state dict must still imply destruction of the
+     corresponding local dicts in all thread-local objects.
+
+   Our implementation uses small "localdummy" objects in order to break
+   the reference chain. These trivial objects are hashable (using the
+   default scheme of identity hashing) and weakrefable.
+   Each thread-state holds a separate localdummy for each local object
+   (as a /strong reference/),
+   and each thread-local object holds a dict mapping /weak references/
+   of localdummies to local dicts.
+
+   Therefore:
+   - only the thread-state dict holds a strong reference to the dummies
+   - only the thread-local object holds a strong reference to the local dicts
+   - only outside objects (application- or library-level) hold strong
+     references to the thread-local objects
+   - as soon as a thread-state dict is destroyed, the weakref callbacks of all
+     dummies attached to that thread are called, and destroy the corresponding
+     local dicts from thread-local objects
+   - as soon as a thread-local object is destroyed, its local dicts are
+     destroyed and its dummies are manually removed from all thread states
+   - the GC can do its work correctly when a thread-local object is dangling,
+     without any interference from the thread-state dicts
+
+   As an additional optimization, each localdummy holds a borrowed reference
+   to the corresponding localdict.  This borrowed reference is only used
+   by the thread-local object which has created the localdummy, which should
+   guarantee that the localdict still exists when accessed.
+*/
+
+typedef struct {
+    PyObject_HEAD
+    PyObject *localdict;        /* Borrowed reference! */
+    PyObject *weakreflist;      /* List of weak references to self */
+} localdummyobject;
+
+static void
+localdummy_dealloc(localdummyobject *self)
+{
+    if (self->weakreflist != NULL)
+        PyObject_ClearWeakRefs((PyObject *) self);
+    Py_TYPE(self)->tp_free((PyObject*)self);
+}
+
+static PyTypeObject localdummytype = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    /* tp_name           */ "_thread._localdummy",
+    /* tp_basicsize      */ sizeof(localdummyobject),
+    /* tp_itemsize       */ 0,
+    /* tp_dealloc        */ (destructor)localdummy_dealloc,
+    /* tp_vectorcall_offset */ 0,
+    /* tp_getattr        */ 0,
+    /* tp_setattr        */ 0,
+    /* tp_as_async       */ 0,
+    /* tp_repr           */ 0,
+    /* tp_as_number      */ 0,
+    /* tp_as_sequence    */ 0,
+    /* tp_as_mapping     */ 0,
+    /* tp_hash           */ 0,
+    /* tp_call           */ 0,
+    /* tp_str            */ 0,
+    /* tp_getattro       */ 0,
+    /* tp_setattro       */ 0,
+    /* tp_as_buffer      */ 0,
+    /* tp_flags          */ Py_TPFLAGS_DEFAULT,
+    /* tp_doc            */ "Thread-local dummy",
+    /* tp_traverse       */ 0,
+    /* tp_clear          */ 0,
+    /* tp_richcompare    */ 0,
+    /* tp_weaklistoffset */ offsetof(localdummyobject, weakreflist)
+};
+
+
+typedef struct {
+    PyObject_HEAD
+    PyObject *key;
+    PyObject *args;
+    PyObject *kw;
+    PyObject *weakreflist;      /* List of weak references to self */
+    /* A {localdummy weakref -> localdict} dict */
+    PyObject *dummies;
+    /* The callback for weakrefs to localdummies */
+    PyObject *wr_callback;
+} localobject;
+
+/* Forward declaration */
+static PyObject *_ldict(localobject *self);
+static PyObject *_localdummy_destroyed(PyObject *meth_self, PyObject *dummyweakref);
+
+/* Create and register the dummy for the current thread.
+   Returns a borrowed reference of the corresponding local dict */
+static PyObject *
+_local_create_dummy(localobject *self)
+{
+    PyObject *tdict, *ldict = NULL, *wr = NULL;
+    localdummyobject *dummy = NULL;
+    int r;
+
+    tdict = PyThreadState_GetDict();
+    if (tdict == NULL) {
+        PyErr_SetString(PyExc_SystemError,
+                        "Couldn't get thread-state dictionary");
+        goto err;
+    }
+
+    ldict = PyDict_New();
+    if (ldict == NULL)
+        goto err;
+    dummy = (localdummyobject *) localdummytype.tp_alloc(&localdummytype, 0);
+    if (dummy == NULL)
+        goto err;
+    dummy->localdict = ldict;
+    wr = PyWeakref_NewRef((PyObject *) dummy, self->wr_callback);
+    if (wr == NULL)
+        goto err;
+
+    /* As a side-effect, this will cache the weakref's hash before the
+       dummy gets deleted */
+    r = PyDict_SetItem(self->dummies, wr, ldict);
+    if (r < 0)
+        goto err;
+    Py_CLEAR(wr);
+    r = PyDict_SetItem(tdict, self->key, (PyObject *) dummy);
+    if (r < 0)
+        goto err;
+    Py_CLEAR(dummy);
+
+    Py_DECREF(ldict);
+    return ldict;
+
+err:
+    Py_XDECREF(ldict);
+    Py_XDECREF(wr);
+    Py_XDECREF(dummy);
+    return NULL;
+}
+
+static PyObject *
+local_new(PyTypeObject *type, PyObject *args, PyObject *kw)
+{
+    localobject *self;
+    PyObject *wr;
+    static PyMethodDef wr_callback_def = {
+        "_localdummy_destroyed", (PyCFunction) _localdummy_destroyed, METH_O
+    };
+
+    if (type->tp_init == PyBaseObject_Type.tp_init) {
+        int rc = 0;
+        if (args != NULL)
+            rc = PyObject_IsTrue(args);
+        if (rc == 0 && kw != NULL)
+            rc = PyObject_IsTrue(kw);
+        if (rc != 0) {
+            if (rc > 0)
+                PyErr_SetString(PyExc_TypeError,
+                          "Initialization arguments are not supported");
+            return NULL;
+        }
+    }
+
+    self = (localobject *)type->tp_alloc(type, 0);
+    if (self == NULL)
+        return NULL;
+
+    Py_XINCREF(args);
+    self->args = args;
+    Py_XINCREF(kw);
+    self->kw = kw;
+    self->key = PyUnicode_FromFormat("thread.local.%p", self);
+    if (self->key == NULL)
+        goto err;
+
+    self->dummies = PyDict_New();
+    if (self->dummies == NULL)
+        goto err;
+
+    /* We use a weak reference to self in the callback closure
+       in order to avoid spurious reference cycles */
+    wr = PyWeakref_NewRef((PyObject *) self, NULL);
+    if (wr == NULL)
+        goto err;
+    self->wr_callback = PyCFunction_NewEx(&wr_callback_def, wr, NULL);
+    Py_DECREF(wr);
+    if (self->wr_callback == NULL)
+        goto err;
+
+    if (_local_create_dummy(self) == NULL)
+        goto err;
+
+    return (PyObject *)self;
+
+  err:
+    Py_DECREF(self);
+    return NULL;
+}
+
+static int
+local_traverse(localobject *self, visitproc visit, void *arg)
+{
+    Py_VISIT(self->args);
+    Py_VISIT(self->kw);
+    Py_VISIT(self->dummies);
+    return 0;
+}
+
+static int
+local_clear(localobject *self)
+{
+    PyThreadState *tstate;
+    Py_CLEAR(self->args);
+    Py_CLEAR(self->kw);
+    Py_CLEAR(self->dummies);
+    Py_CLEAR(self->wr_callback);
+    /* Remove all strong references to dummies from the thread states */
+    if (self->key
+        && (tstate = PyThreadState_Get())
+        && tstate->interp) {
+        for(tstate = PyInterpreterState_ThreadHead(tstate->interp);
+            tstate;
+            tstate = PyThreadState_Next(tstate))
+            if (tstate->dict && PyDict_GetItem(tstate->dict, self->key)) {
+                if (PyDict_DelItem(tstate->dict, self->key)) {
+                    PyErr_Clear();
+                }
+            }
+    }
+    return 0;
+}
+
+static void
+local_dealloc(localobject *self)
+{
+    /* Weakrefs must be invalidated right now, otherwise they can be used
+       from code called below, which is very dangerous since Py_REFCNT(self) == 0 */
+    if (self->weakreflist != NULL)
+        PyObject_ClearWeakRefs((PyObject *) self);
+
+    PyObject_GC_UnTrack(self);
+
+    local_clear(self);
+    Py_XDECREF(self->key);
+    Py_TYPE(self)->tp_free((PyObject*)self);
+}
+
+/* Returns a borrowed reference to the local dict, creating it if necessary */
+static PyObject *
+_ldict(localobject *self)
+{
+    PyObject *tdict, *ldict, *dummy;
+
+    tdict = PyThreadState_GetDict();
+    if (tdict == NULL) {
+        PyErr_SetString(PyExc_SystemError,
+                        "Couldn't get thread-state dictionary");
+        return NULL;
+    }
+
+    dummy = PyDict_GetItemWithError(tdict, self->key);
+    if (dummy == NULL) {
+        if (PyErr_Occurred()) {
+            return NULL;
+        }
+        ldict = _local_create_dummy(self);
+        if (ldict == NULL)
+            return NULL;
+
+        if (Py_TYPE(self)->tp_init != PyBaseObject_Type.tp_init &&
+            Py_TYPE(self)->tp_init((PyObject*)self,
+                                   self->args, self->kw) < 0) {
+            /* we need to get rid of ldict from thread so
+               we create a new one the next time we do an attr
+               access */
+            PyDict_DelItem(tdict, self->key);
+            return NULL;
+        }
+    }
+    else {
+        assert(Py_IS_TYPE(dummy, &localdummytype));
+        ldict = ((localdummyobject *) dummy)->localdict;
+    }
+
+    return ldict;
+}
+
+static int
+local_setattro(localobject *self, PyObject *name, PyObject *v)
+{
+    PyObject *ldict;
+    int r;
+
+    ldict = _ldict(self);
+    if (ldict == NULL)
+        return -1;
+
+    r = PyObject_RichCompareBool(name, str_dict, Py_EQ);
+    if (r == 1) {
+        PyErr_Format(PyExc_AttributeError,
+                     "'%.50s' object attribute '%U' is read-only",
+                     Py_TYPE(self)->tp_name, name);
+        return -1;
+    }
+    if (r == -1)
+        return -1;
+
+    return _PyObject_GenericSetAttrWithDict((PyObject *)self, name, v, ldict);
+}
+
+static PyObject *local_getattro(localobject *, PyObject *);
+
+static PyTypeObject localtype = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    /* tp_name           */ "_thread._local",
+    /* tp_basicsize      */ sizeof(localobject),
+    /* tp_itemsize       */ 0,
+    /* tp_dealloc        */ (destructor)local_dealloc,
+    /* tp_vectorcall_offset */ 0,
+    /* tp_getattr        */ 0,
+    /* tp_setattr        */ 0,
+    /* tp_as_async       */ 0,
+    /* tp_repr           */ 0,
+    /* tp_as_number      */ 0,
+    /* tp_as_sequence    */ 0,
+    /* tp_as_mapping     */ 0,
+    /* tp_hash           */ 0,
+    /* tp_call           */ 0,
+    /* tp_str            */ 0,
+    /* tp_getattro       */ (getattrofunc)local_getattro,
+    /* tp_setattro       */ (setattrofunc)local_setattro,
+    /* tp_as_buffer      */ 0,
+    /* tp_flags          */ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE
+                                               | Py_TPFLAGS_HAVE_GC,
+    /* tp_doc            */ "Thread-local data",
+    /* tp_traverse       */ (traverseproc)local_traverse,
+    /* tp_clear          */ (inquiry)local_clear,
+    /* tp_richcompare    */ 0,
+    /* tp_weaklistoffset */ offsetof(localobject, weakreflist),
+    /* tp_iter           */ 0,
+    /* tp_iternext       */ 0,
+    /* tp_methods        */ 0,
+    /* tp_members        */ 0,
+    /* tp_getset         */ 0,
+    /* tp_base           */ 0,
+    /* tp_dict           */ 0, /* internal use */
+    /* tp_descr_get      */ 0,
+    /* tp_descr_set      */ 0,
+    /* tp_dictoffset     */ 0,
+    /* tp_init           */ 0,
+    /* tp_alloc          */ 0,
+    /* tp_new            */ local_new,
+    /* tp_free           */ 0, /* Low-level free-mem routine */
+    /* tp_is_gc          */ 0, /* For PyObject_IS_GC */
+};
+
+static PyObject *
+local_getattro(localobject *self, PyObject *name)
+{
+    PyObject *ldict, *value;
+    int r;
+
+    ldict = _ldict(self);
+    if (ldict == NULL)
+        return NULL;
+
+    r = PyObject_RichCompareBool(name, str_dict, Py_EQ);
+    if (r == 1) {
+        Py_INCREF(ldict);
+        return ldict;
+    }
+    if (r == -1)
+        return NULL;
+
+    if (!Py_IS_TYPE(self, &localtype))
+        /* use generic lookup for subtypes */
+        return _PyObject_GenericGetAttrWithDict(
+            (PyObject *)self, name, ldict, 0);
+
+    /* Optimization: just look in dict ourselves */
+    value = PyDict_GetItemWithError(ldict, name);
+    if (value != NULL) {
+        Py_INCREF(value);
+        return value;
+    }
+    else if (PyErr_Occurred()) {
+        return NULL;
+    }
+    /* Fall back on generic to get __class__ and __dict__ */
+    return _PyObject_GenericGetAttrWithDict(
+        (PyObject *)self, name, ldict, 0);
+}
+
+/* Called when a dummy is destroyed. */
+static PyObject *
+_localdummy_destroyed(PyObject *localweakref, PyObject *dummyweakref)
+{
+    PyObject *obj;
+    localobject *self;
+    assert(PyWeakref_CheckRef(localweakref));
+    obj = PyWeakref_GET_OBJECT(localweakref);
+    if (obj == Py_None)
+        Py_RETURN_NONE;
+    Py_INCREF(obj);
+    assert(PyObject_TypeCheck(obj, &localtype));
+    /* If the thread-local object is still alive and not being cleared,
+       remove the corresponding local dict */
+    self = (localobject *) obj;
+    if (self->dummies != NULL) {
+        PyObject *ldict;
+        ldict = PyDict_GetItemWithError(self->dummies, dummyweakref);
+        if (ldict != NULL) {
+            PyDict_DelItem(self->dummies, dummyweakref);
+        }
+        if (PyErr_Occurred())
+            PyErr_WriteUnraisable(obj);
+    }
+    Py_DECREF(obj);
+    Py_RETURN_NONE;
+}
+
+/* Module functions */
+
+struct bootstate {
+    PyInterpreterState *interp;
+    PyObject *func;
+    PyObject *args;
+    PyObject *keyw;
+    PyThreadState *tstate;
+    _PyRuntimeState *runtime;
+};
+
+static void
+t_bootstrap(void *boot_raw)
+{
+    struct bootstate *boot = (struct bootstate *) boot_raw;
+    PyThreadState *tstate;
+    PyObject *res;
+
+    tstate = boot->tstate;
+    tstate->thread_id = PyThread_get_thread_ident();
+    _PyThreadState_Init(tstate);
+    PyEval_AcquireThread(tstate);
+    tstate->interp->num_threads++;
+    res = PyObject_Call(boot->func, boot->args, boot->keyw);
+    if (res == NULL) {
+        if (PyErr_ExceptionMatches(PyExc_SystemExit))
+            /* SystemExit is ignored silently */
+            PyErr_Clear();
+        else {
+            _PyErr_WriteUnraisableMsg("in thread started by", boot->func);
+        }
+    }
+    else {
+        Py_DECREF(res);
+    }
+    Py_DECREF(boot->func);
+    Py_DECREF(boot->args);
+    Py_XDECREF(boot->keyw);
+    PyMem_DEL(boot_raw);
+    tstate->interp->num_threads--;
+    PyThreadState_Clear(tstate);
+    _PyThreadState_DeleteCurrent(tstate);
+
+    // bpo-44434: Don't call explicitly PyThread_exit_thread(). On Linux with
+    // the glibc, pthread_exit() can abort the whole process if dlopen() fails
+    // to open the libgcc_s.so library (ex: EMFILE error).
+}
+
+static PyObject *
+thread_PyThread_start_new_thread(PyObject *self, PyObject *fargs)
+{
+    _PyRuntimeState *runtime = &_PyRuntime;
+    PyObject *func, *args, *keyw = NULL;
+    struct bootstate *boot;
+    unsigned long ident;
+
+    if (!PyArg_UnpackTuple(fargs, "start_new_thread", 2, 3,
+                           &func, &args, &keyw))
+        return NULL;
+    if (!PyCallable_Check(func)) {
+        PyErr_SetString(PyExc_TypeError,
+                        "first arg must be callable");
+        return NULL;
+    }
+    if (!PyTuple_Check(args)) {
+        PyErr_SetString(PyExc_TypeError,
+                        "2nd arg must be a tuple");
+        return NULL;
+    }
+    if (keyw != NULL && !PyDict_Check(keyw)) {
+        PyErr_SetString(PyExc_TypeError,
+                        "optional 3rd arg must be a dictionary");
+        return NULL;
+    }
+
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    if (interp->config._isolated_interpreter) {
+        PyErr_SetString(PyExc_RuntimeError,
+                        "thread is not supported for isolated subinterpreters");
+        return NULL;
+    }
+
+    boot = PyMem_NEW(struct bootstate, 1);
+    if (boot == NULL)
+        return PyErr_NoMemory();
+    boot->interp = _PyInterpreterState_GET();
+    boot->func = func;
+    boot->args = args;
+    boot->keyw = keyw;
+    boot->tstate = _PyThreadState_Prealloc(boot->interp);
+    boot->runtime = runtime;
+    if (boot->tstate == NULL) {
+        PyMem_DEL(boot);
+        return PyErr_NoMemory();
+    }
+    Py_INCREF(func);
+    Py_INCREF(args);
+    Py_XINCREF(keyw);
+
+    ident = PyThread_start_new_thread(t_bootstrap, (void*) boot);
+    if (ident == PYTHREAD_INVALID_THREAD_ID) {
+        PyErr_SetString(ThreadError, "can't start new thread");
+        Py_DECREF(func);
+        Py_DECREF(args);
+        Py_XDECREF(keyw);
+        PyThreadState_Clear(boot->tstate);
+        PyMem_DEL(boot);
+        return NULL;
+    }
+    return PyLong_FromUnsignedLong(ident);
+}
+
+PyDoc_STRVAR(start_new_doc,
+"start_new_thread(function, args[, kwargs])\n\
+(start_new() is an obsolete synonym)\n\
+\n\
+Start a new thread and return its identifier.  The thread will call the\n\
+function with positional arguments from the tuple args and keyword arguments\n\
+taken from the optional dictionary kwargs.  The thread exits when the\n\
+function returns; the return value is ignored.  The thread will also exit\n\
+when the function raises an unhandled exception; a stack trace will be\n\
+printed unless the exception is SystemExit.\n");
+
+static PyObject *
+thread_PyThread_exit_thread(PyObject *self, PyObject *Py_UNUSED(ignored))
+{
+    PyErr_SetNone(PyExc_SystemExit);
+    return NULL;
+}
+
+PyDoc_STRVAR(exit_doc,
+"exit()\n\
+(exit_thread() is an obsolete synonym)\n\
+\n\
+This is synonymous to ``raise SystemExit''.  It will cause the current\n\
+thread to exit silently unless the exception is caught.");
+
+static PyObject *
+thread_PyThread_interrupt_main(PyObject * self, PyObject *Py_UNUSED(ignored))
+{
+    PyErr_SetInterrupt();
+    Py_RETURN_NONE;
+}
+
+PyDoc_STRVAR(interrupt_doc,
+"interrupt_main()\n\
+\n\
+Raise a KeyboardInterrupt in the main thread.\n\
+A subthread can use this function to interrupt the main thread."
+);
+
+static lockobject *newlockobject(void);
+
+static PyObject *
+thread_PyThread_allocate_lock(PyObject *self, PyObject *Py_UNUSED(ignored))
+{
+    return (PyObject *) newlockobject();
+}
+
+PyDoc_STRVAR(allocate_doc,
+"allocate_lock() -> lock object\n\
+(allocate() is an obsolete synonym)\n\
+\n\
+Create a new lock object. See help(type(threading.Lock())) for\n\
+information about locks.");
+
+static PyObject *
+thread_get_ident(PyObject *self, PyObject *Py_UNUSED(ignored))
+{
+    unsigned long ident = PyThread_get_thread_ident();
+    if (ident == PYTHREAD_INVALID_THREAD_ID) {
+        PyErr_SetString(ThreadError, "no current thread ident");
+        return NULL;
+    }
+    return PyLong_FromUnsignedLong(ident);
+}
+
+PyDoc_STRVAR(get_ident_doc,
+"get_ident() -> integer\n\
+\n\
+Return a non-zero integer that uniquely identifies the current thread\n\
+amongst other threads that exist simultaneously.\n\
+This may be used to identify per-thread resources.\n\
+Even though on some platforms threads identities may appear to be\n\
+allocated consecutive numbers starting at 1, this behavior should not\n\
+be relied upon, and the number should be seen purely as a magic cookie.\n\
+A thread's identity may be reused for another thread after it exits.");
+
+#ifdef PY_HAVE_THREAD_NATIVE_ID
+static PyObject *
+thread_get_native_id(PyObject *self, PyObject *Py_UNUSED(ignored))
+{
+    unsigned long native_id = PyThread_get_thread_native_id();
+    return PyLong_FromUnsignedLong(native_id);
+}
+
+PyDoc_STRVAR(get_native_id_doc,
+"get_native_id() -> integer\n\
+\n\
+Return a non-negative integer identifying the thread as reported\n\
+by the OS (kernel). This may be used to uniquely identify a\n\
+particular thread within a system.");
+#endif
+
+static PyObject *
+thread__count(PyObject *self, PyObject *Py_UNUSED(ignored))
+{
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    return PyLong_FromLong(interp->num_threads);
+}
+
+PyDoc_STRVAR(_count_doc,
+"_count() -> integer\n\
+\n\
+\
+Return the number of currently running Python threads, excluding\n\
+the main thread. The returned number comprises all threads created\n\
+through `start_new_thread()` as well as `threading.Thread`, and not\n\
+yet finished.\n\
+\n\
+This function is meant for internal and specialized purposes only.\n\
+In most applications `threading.enumerate()` should be used instead.");
+
+static void
+release_sentinel(void *wr_raw)
+{
+    PyObject *wr = _PyObject_CAST(wr_raw);
+    /* Tricky: this function is called when the current thread state
+       is being deleted.  Therefore, only simple C code can safely
+       execute here. */
+    PyObject *obj = PyWeakref_GET_OBJECT(wr);
+    lockobject *lock;
+    if (obj != Py_None) {
+        assert(Py_IS_TYPE(obj, &Locktype));
+        lock = (lockobject *) obj;
+        if (lock->locked) {
+            PyThread_release_lock(lock->lock_lock);
+            lock->locked = 0;
+        }
+    }
+    /* Deallocating a weakref with a NULL callback only calls
+       PyObject_GC_Del(), which can't call any Python code. */
+    Py_DECREF(wr);
+}
+
+static PyObject *
+thread__set_sentinel(PyObject *self, PyObject *Py_UNUSED(ignored))
+{
+    PyObject *wr;
+    PyThreadState *tstate = PyThreadState_Get();
+    lockobject *lock;
+
+    if (tstate->on_delete_data != NULL) {
+        /* We must support the re-creation of the lock from a
+           fork()ed child. */
+        assert(tstate->on_delete == &release_sentinel);
+        wr = (PyObject *) tstate->on_delete_data;
+        tstate->on_delete = NULL;
+        tstate->on_delete_data = NULL;
+        Py_DECREF(wr);
+    }
+    lock = newlockobject();
+    if (lock == NULL)
+        return NULL;
+    /* The lock is owned by whoever called _set_sentinel(), but the weakref
+       hangs to the thread state. */
+    wr = PyWeakref_NewRef((PyObject *) lock, NULL);
+    if (wr == NULL) {
+        Py_DECREF(lock);
+        return NULL;
+    }
+    tstate->on_delete_data = (void *) wr;
+    tstate->on_delete = &release_sentinel;
+    return (PyObject *) lock;
+}
+
+PyDoc_STRVAR(_set_sentinel_doc,
+"_set_sentinel() -> lock\n\
+\n\
+Set a sentinel lock that will be released when the current thread\n\
+state is finalized (after it is untied from the interpreter).\n\
+\n\
+This is a private API for the threading module.");
+
+static PyObject *
+thread_stack_size(PyObject *self, PyObject *args)
+{
+    size_t old_size;
+    Py_ssize_t new_size = 0;
+    int rc;
+
+    if (!PyArg_ParseTuple(args, "|n:stack_size", &new_size))
+        return NULL;
+
+    if (new_size < 0) {
+        PyErr_SetString(PyExc_ValueError,
+                        "size must be 0 or a positive value");
+        return NULL;
+    }
+
+    old_size = PyThread_get_stacksize();
+
+    rc = PyThread_set_stacksize((size_t) new_size);
+    if (rc == -1) {
+        PyErr_Format(PyExc_ValueError,
+                     "size not valid: %zd bytes",
+                     new_size);
+        return NULL;
+    }
+    if (rc == -2) {
+        PyErr_SetString(ThreadError,
+                        "setting stack size not supported");
+        return NULL;
+    }
+
+    return PyLong_FromSsize_t((Py_ssize_t) old_size);
+}
+
+PyDoc_STRVAR(stack_size_doc,
+"stack_size([size]) -> size\n\
+\n\
+Return the thread stack size used when creating new threads.  The\n\
+optional size argument specifies the stack size (in bytes) to be used\n\
+for subsequently created threads, and must be 0 (use platform or\n\
+configured default) or a positive integer value of at least 32,768 (32k).\n\
+If changing the thread stack size is unsupported, a ThreadError\n\
+exception is raised.  If the specified size is invalid, a ValueError\n\
+exception is raised, and the stack size is unmodified.  32k bytes\n\
+ currently the minimum supported stack size value to guarantee\n\
+sufficient stack space for the interpreter itself.\n\
+\n\
+Note that some platforms may have particular restrictions on values for\n\
+the stack size, such as requiring a minimum stack size larger than 32 KiB or\n\
+requiring allocation in multiples of the system memory page size\n\
+- platform documentation should be referred to for more information\n\
+(4 KiB pages are common; using multiples of 4096 for the stack size is\n\
+the suggested approach in the absence of more specific information).");
+
+static int
+thread_excepthook_file(PyObject *file, PyObject *exc_type, PyObject *exc_value,
+                       PyObject *exc_traceback, PyObject *thread)
+{
+    _Py_IDENTIFIER(name);
+    /* print(f"Exception in thread {thread.name}:", file=file) */
+    if (PyFile_WriteString("Exception in thread ", file) < 0) {
+        return -1;
+    }
+
+    PyObject *name = NULL;
+    if (thread != Py_None) {
+        if (_PyObject_LookupAttrId(thread, &PyId_name, &name) < 0) {
+            return -1;
+        }
+    }
+    if (name != NULL) {
+        if (PyFile_WriteObject(name, file, Py_PRINT_RAW) < 0) {
+            Py_DECREF(name);
+            return -1;
+        }
+        Py_DECREF(name);
+    }
+    else {
+        unsigned long ident = PyThread_get_thread_ident();
+        PyObject *str = PyUnicode_FromFormat("%lu", ident);
+        if (str != NULL) {
+            if (PyFile_WriteObject(str, file, Py_PRINT_RAW) < 0) {
+                Py_DECREF(str);
+                return -1;
+            }
+            Py_DECREF(str);
+        }
+        else {
+            PyErr_Clear();
+
+            if (PyFile_WriteString("<failed to get thread name>", file) < 0) {
+                return -1;
+            }
+        }
+    }
+
+    if (PyFile_WriteString(":\n", file) < 0) {
+        return -1;
+    }
+
+    /* Display the traceback */
+    _PyErr_Display(file, exc_type, exc_value, exc_traceback);
+
+    /* Call file.flush() */
+    PyObject *res = _PyObject_CallMethodIdNoArgs(file, &PyId_flush);
+    if (!res) {
+        return -1;
+    }
+    Py_DECREF(res);
+
+    return 0;
+}
+
+
+PyDoc_STRVAR(ExceptHookArgs__doc__,
+"ExceptHookArgs\n\
+\n\
+Type used to pass arguments to threading.excepthook.");
+
+static PyTypeObject ExceptHookArgsType;
+
+static PyStructSequence_Field ExceptHookArgs_fields[] = {
+    {"exc_type", "Exception type"},
+    {"exc_value", "Exception value"},
+    {"exc_traceback", "Exception traceback"},
+    {"thread", "Thread"},
+    {0}
+};
+
+static PyStructSequence_Desc ExceptHookArgs_desc = {
+    .name = "_thread.ExceptHookArgs",
+    .doc = ExceptHookArgs__doc__,
+    .fields = ExceptHookArgs_fields,
+    .n_in_sequence = 4
+};
+
+
+static PyObject *
+thread_excepthook(PyObject *self, PyObject *args)
+{
+    if (!Py_IS_TYPE(args, &ExceptHookArgsType)) {
+        PyErr_SetString(PyExc_TypeError,
+                        "_thread.excepthook argument type "
+                        "must be ExceptHookArgs");
+        return NULL;
+    }
+
+    /* Borrowed reference */
+    PyObject *exc_type = PyStructSequence_GET_ITEM(args, 0);
+    if (exc_type == PyExc_SystemExit) {
+        /* silently ignore SystemExit */
+        Py_RETURN_NONE;
+    }
+
+    /* Borrowed references */
+    PyObject *exc_value = PyStructSequence_GET_ITEM(args, 1);
+    PyObject *exc_tb = PyStructSequence_GET_ITEM(args, 2);
+    PyObject *thread = PyStructSequence_GET_ITEM(args, 3);
+
+    PyObject *file = _PySys_GetObjectId(&PyId_stderr);
+    if (file == NULL || file == Py_None) {
+        if (thread == Py_None) {
+            /* do nothing if sys.stderr is None and thread is None */
+            Py_RETURN_NONE;
+        }
+
+        file = PyObject_GetAttrString(thread, "_stderr");
+        if (file == NULL) {
+            return NULL;
+        }
+        if (file == Py_None) {
+            Py_DECREF(file);
+            /* do nothing if sys.stderr is None and sys.stderr was None
+               when the thread was created */
+            Py_RETURN_NONE;
+        }
+    }
+    else {
+        Py_INCREF(file);
+    }
+
+    int res = thread_excepthook_file(file, exc_type, exc_value, exc_tb,
+                                     thread);
+    Py_DECREF(file);
+    if (res < 0) {
+        return NULL;
+    }
+
+    Py_RETURN_NONE;
+}
+
+PyDoc_STRVAR(excepthook_doc,
+"excepthook(exc_type, exc_value, exc_traceback, thread)\n\
+\n\
+Handle uncaught Thread.run() exception.");
+
+static PyMethodDef thread_methods[] = {
+    {"start_new_thread",        (PyCFunction)thread_PyThread_start_new_thread,
+     METH_VARARGS, start_new_doc},
+    {"start_new",               (PyCFunction)thread_PyThread_start_new_thread,
+     METH_VARARGS, start_new_doc},
+    {"allocate_lock",           thread_PyThread_allocate_lock,
+     METH_NOARGS, allocate_doc},
+    {"allocate",                thread_PyThread_allocate_lock,
+     METH_NOARGS, allocate_doc},
+    {"exit_thread",             thread_PyThread_exit_thread,
+     METH_NOARGS, exit_doc},
+    {"exit",                    thread_PyThread_exit_thread,
+     METH_NOARGS, exit_doc},
+    {"interrupt_main",          thread_PyThread_interrupt_main,
+     METH_NOARGS, interrupt_doc},
+    {"get_ident",               thread_get_ident,
+     METH_NOARGS, get_ident_doc},
+#ifdef PY_HAVE_THREAD_NATIVE_ID
+    {"get_native_id",           thread_get_native_id,
+     METH_NOARGS, get_native_id_doc},
+#endif
+    {"_count",                  thread__count,
+     METH_NOARGS, _count_doc},
+    {"stack_size",              (PyCFunction)thread_stack_size,
+     METH_VARARGS, stack_size_doc},
+    {"_set_sentinel",           thread__set_sentinel,
+     METH_NOARGS, _set_sentinel_doc},
+    {"_excepthook",              thread_excepthook,
+     METH_O, excepthook_doc},
+    {NULL,                      NULL}           /* sentinel */
+};
+
+
+/* Initialization function */
+
+PyDoc_STRVAR(thread_doc,
+"This module provides primitive operations to write multi-threaded programs.\n\
+The 'threading' module provides a more convenient interface.");
+
+PyDoc_STRVAR(lock_doc,
+"A lock object is a synchronization primitive.  To create a lock,\n\
+call threading.Lock().  Methods are:\n\
+\n\
+acquire() -- lock the lock, possibly blocking until it can be obtained\n\
+release() -- unlock of the lock\n\
+locked() -- test whether the lock is currently locked\n\
+\n\
+A lock is not owned by the thread that locked it; another thread may\n\
+unlock it.  A thread attempting to lock a lock that it has already locked\n\
+will block until another thread unlocks it.  Deadlocks may ensue.");
+
+static struct PyModuleDef threadmodule = {
+    PyModuleDef_HEAD_INIT,
+    "_thread",
+    thread_doc,
+    -1,
+    thread_methods,
+    NULL,
+    NULL,
+    NULL,
+    NULL
+};
+
+
+PyMODINIT_FUNC
+PyInit__thread(void)
+{
+    PyObject *m, *d, *v;
+    double time_max;
+    double timeout_max;
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+
+    /* Initialize types: */
+    if (PyType_Ready(&localdummytype) < 0)
+        return NULL;
+    if (PyType_Ready(&localtype) < 0)
+        return NULL;
+    if (PyType_Ready(&Locktype) < 0)
+        return NULL;
+    if (PyType_Ready(&RLocktype) < 0)
+        return NULL;
+    if (ExceptHookArgsType.tp_name == NULL) {
+        if (PyStructSequence_InitType2(&ExceptHookArgsType,
+                                       &ExceptHookArgs_desc) < 0) {
+            return NULL;
+        }
+    }
+
+    /* Create the module and add the functions */
+    m = PyModule_Create(&threadmodule);
+    if (m == NULL)
+        return NULL;
+
+    timeout_max = (_PyTime_t)PY_TIMEOUT_MAX * 1e-6;
+    time_max = _PyTime_AsSecondsDouble(_PyTime_MAX);
+    timeout_max = Py_MIN(timeout_max, time_max);
+    /* Round towards minus infinity */
+    timeout_max = floor(timeout_max);
+
+    v = PyFloat_FromDouble(timeout_max);
+    if (!v)
+        return NULL;
+    if (PyModule_AddObject(m, "TIMEOUT_MAX", v) < 0)
+        return NULL;
+
+    /* Add a symbolic constant */
+    d = PyModule_GetDict(m);
+    ThreadError = PyExc_RuntimeError;
+    Py_INCREF(ThreadError);
+
+    PyDict_SetItemString(d, "error", ThreadError);
+    Locktype.tp_doc = lock_doc;
+    Py_INCREF(&Locktype);
+    PyDict_SetItemString(d, "LockType", (PyObject *)&Locktype);
+
+    Py_INCREF(&RLocktype);
+    if (PyModule_AddObject(m, "RLock", (PyObject *)&RLocktype) < 0)
+        return NULL;
+
+    Py_INCREF(&localtype);
+    if (PyModule_AddObject(m, "_local", (PyObject *)&localtype) < 0)
+        return NULL;
+
+    Py_INCREF(&ExceptHookArgsType);
+    if (PyModule_AddObject(m, "_ExceptHookArgs",
+                           (PyObject *)&ExceptHookArgsType) < 0)
+        return NULL;
+
+    interp->num_threads = 0;
+
+    str_dict = PyUnicode_InternFromString("__dict__");
+    if (str_dict == NULL)
+        return NULL;
+
+    /* Initialize the C thread library */
+    PyThread_init_thread();
+    return m;
+}