/* Locking in multithreaded situations.
- Copyright (C) 2005-2016 Free Software Foundation, Inc.
+ Copyright (C) 2005-2019 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, see <http://www.gnu.org/licenses/>. */
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <bruno@clisp.org>, 2005.
- Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-solaris.h,
- gthr-win32.h. */
+ Based on GCC's gthr-posix.h, gthr-posix95.h. */
#include <config.h>
/* ========================================================================= */
+#if USE_ISOC_THREADS || USE_ISOC_AND_POSIX_THREADS
+
+/* -------------------------- gl_lock_t datatype -------------------------- */
+
+int
+glthread_lock_init (gl_lock_t *lock)
+{
+ if (mtx_init (&lock->mutex, mtx_plain) != thrd_success)
+ return ENOMEM;
+ lock->init_needed = 0;
+ return 0;
+}
+
+int
+glthread_lock_lock (gl_lock_t *lock)
+{
+ if (lock->init_needed)
+ call_once (&lock->init_once, lock->init_func);
+ if (mtx_lock (&lock->mutex) != thrd_success)
+ return EAGAIN;
+ return 0;
+}
+
+int
+glthread_lock_unlock (gl_lock_t *lock)
+{
+ if (lock->init_needed)
+ call_once (&lock->init_once, lock->init_func);
+ if (mtx_unlock (&lock->mutex) != thrd_success)
+ return EINVAL;
+ return 0;
+}
+
+int
+glthread_lock_destroy (gl_lock_t *lock)
+{
+ if (lock->init_needed)
+ call_once (&lock->init_once, lock->init_func);
+ mtx_destroy (&lock->mutex);
+ return 0;
+}
+
+/* ------------------------- gl_rwlock_t datatype ------------------------- */
+
+int
+glthread_rwlock_init (gl_rwlock_t *lock)
+{
+ if (mtx_init (&lock->lock, mtx_plain) != thrd_success
+ || cnd_init (&lock->waiting_readers) != thrd_success
+ || cnd_init (&lock->waiting_writers) != thrd_success)
+ return ENOMEM;
+ lock->waiting_writers_count = 0;
+ lock->runcount = 0;
+ lock->init_needed = 0;
+ return 0;
+}
+
+int
+glthread_rwlock_rdlock (gl_rwlock_t *lock)
+{
+ if (lock->init_needed)
+ call_once (&lock->init_once, lock->init_func);
+ if (mtx_lock (&lock->lock) != thrd_success)
+ return EAGAIN;
+ /* Test whether only readers are currently running, and whether the runcount
+ field will not overflow, and whether no writer is waiting. The latter
+ condition is because POSIX recommends that "write locks shall take
+ precedence over read locks", to avoid "writer starvation". */
+ while (!(lock->runcount + 1 > 0 && lock->waiting_writers_count == 0))
+ {
+ /* This thread has to wait for a while. Enqueue it among the
+ waiting_readers. */
+ if (cnd_wait (&lock->waiting_readers, &lock->lock) != thrd_success)
+ {
+ mtx_unlock (&lock->lock);
+ return EINVAL;
+ }
+ }
+ lock->runcount++;
+ if (mtx_unlock (&lock->lock) != thrd_success)
+ return EINVAL;
+ return 0;
+}
+
+int
+glthread_rwlock_wrlock (gl_rwlock_t *lock)
+{
+ if (lock->init_needed)
+ call_once (&lock->init_once, lock->init_func);
+ if (mtx_lock (&lock->lock) != thrd_success)
+ return EAGAIN;
+ /* Test whether no readers or writers are currently running. */
+ while (!(lock->runcount == 0))
+ {
+ /* This thread has to wait for a while. Enqueue it among the
+ waiting_writers. */
+ lock->waiting_writers_count++;
+ if (cnd_wait (&lock->waiting_writers, &lock->lock) != thrd_success)
+ {
+ lock->waiting_writers_count--;
+ mtx_unlock (&lock->lock);
+ return EINVAL;
+ }
+ lock->waiting_writers_count--;
+ }
+ lock->runcount--; /* runcount becomes -1 */
+ if (mtx_unlock (&lock->lock) != thrd_success)
+ return EINVAL;
+ return 0;
+}
+
+int
+glthread_rwlock_unlock (gl_rwlock_t *lock)
+{
+ if (lock->init_needed)
+ call_once (&lock->init_once, lock->init_func);
+ if (mtx_lock (&lock->lock) != thrd_success)
+ return EAGAIN;
+ if (lock->runcount < 0)
+ {
+ /* Drop a writer lock. */
+ if (!(lock->runcount == -1))
+ {
+ mtx_unlock (&lock->lock);
+ return EINVAL;
+ }
+ lock->runcount = 0;
+ }
+ else
+ {
+ /* Drop a reader lock. */
+ if (!(lock->runcount > 0))
+ {
+ mtx_unlock (&lock->lock);
+ return EINVAL;
+ }
+ lock->runcount--;
+ }
+ if (lock->runcount == 0)
+ {
+ /* POSIX recommends that "write locks shall take precedence over read
+ locks", to avoid "writer starvation". */
+ if (lock->waiting_writers_count > 0)
+ {
+ /* Wake up one of the waiting writers. */
+ if (cnd_signal (&lock->waiting_writers) != thrd_success)
+ {
+ mtx_unlock (&lock->lock);
+ return EINVAL;
+ }
+ }
+ else
+ {
+ /* Wake up all waiting readers. */
+ if (cnd_broadcast (&lock->waiting_readers) != thrd_success)
+ {
+ mtx_unlock (&lock->lock);
+ return EINVAL;
+ }
+ }
+ }
+ if (mtx_unlock (&lock->lock) != thrd_success)
+ return EINVAL;
+ return 0;
+}
+
+int
+glthread_rwlock_destroy (gl_rwlock_t *lock)
+{
+ if (lock->init_needed)
+ call_once (&lock->init_once, lock->init_func);
+ mtx_destroy (&lock->lock);
+ cnd_destroy (&lock->waiting_readers);
+ cnd_destroy (&lock->waiting_writers);
+ return 0;
+}
+
+/* --------------------- gl_recursive_lock_t datatype --------------------- */
+
+int
+glthread_recursive_lock_init (gl_recursive_lock_t *lock)
+{
+ if (mtx_init (&lock->mutex, mtx_plain | mtx_recursive) != thrd_success)
+ return ENOMEM;
+ lock->init_needed = 0;
+ return 0;
+}
+
+int
+glthread_recursive_lock_lock (gl_recursive_lock_t *lock)
+{
+ if (lock->init_needed)
+ call_once (&lock->init_once, lock->init_func);
+ if (mtx_lock (&lock->mutex) != thrd_success)
+ return EAGAIN;
+ return 0;
+}
+
+int
+glthread_recursive_lock_unlock (gl_recursive_lock_t *lock)
+{
+ if (lock->init_needed)
+ call_once (&lock->init_once, lock->init_func);
+ if (mtx_unlock (&lock->mutex) != thrd_success)
+ return EINVAL;
+ return 0;
+}
+
+int
+glthread_recursive_lock_destroy (gl_recursive_lock_t *lock)
+{
+ if (lock->init_needed)
+ call_once (&lock->init_once, lock->init_func);
+ mtx_destroy (&lock->mutex);
+ return 0;
+}
+
+/* -------------------------- gl_once_t datatype -------------------------- */
+
+#endif
+
+/* ========================================================================= */
+
#if USE_POSIX_THREADS
/* -------------------------- gl_lock_t datatype -------------------------- */
/* ------------------------- gl_rwlock_t datatype ------------------------- */
-# if HAVE_PTHREAD_RWLOCK
+# if HAVE_PTHREAD_RWLOCK && (HAVE_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER || (defined PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP && (__GNU_LIBRARY__ > 1)))
+
+# ifdef PTHREAD_RWLOCK_INITIALIZER
+
+# if !HAVE_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER
+ /* glibc with bug https://sourceware.org/bugzilla/show_bug.cgi?id=13701 */
+
+int
+glthread_rwlock_init_for_glibc (pthread_rwlock_t *lock)
+{
+ pthread_rwlockattr_t attributes;
+ int err;
-# if !defined PTHREAD_RWLOCK_INITIALIZER
+ err = pthread_rwlockattr_init (&attributes);
+ if (err != 0)
+ return err;
+ /* Note: PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP is the only value that
+ causes the writer to be preferred. PTHREAD_RWLOCK_PREFER_WRITER_NP does not
+ do this; see
+ http://man7.org/linux/man-pages/man3/pthread_rwlockattr_setkind_np.3.html */
+ err = pthread_rwlockattr_setkind_np (&attributes,
+ PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP);
+ if (err == 0)
+ err = pthread_rwlock_init(lock, &attributes);
+ /* pthread_rwlockattr_destroy always returns 0. It cannot influence the
+ return value. */
+ pthread_rwlockattr_destroy (&attributes);
+ return err;
+}
+
+# endif
+# else
int
glthread_rwlock_init_multithreaded (gl_rwlock_t *lock)
if (err != 0)
return err;
/* Test whether only readers are currently running, and whether the runcount
- field will not overflow. */
- /* POSIX says: "It is implementation-defined whether the calling thread
- acquires the lock when a writer does not hold the lock and there are
- writers blocked on the lock." Let's say, no: give the writers a higher
- priority. */
+ field will not overflow, and whether no writer is waiting. The latter
+ condition is because POSIX recommends that "write locks shall take
+ precedence over read locks", to avoid "writer starvation". */
while (!(lock->runcount + 1 > 0 && lock->waiting_writers_count == 0))
{
/* This thread has to wait for a while. Enqueue it among the
/* ========================================================================= */
-#if USE_PTH_THREADS
-
-/* Use the GNU Pth threads library. */
-
-/* -------------------------- gl_lock_t datatype -------------------------- */
-
-/* ------------------------- gl_rwlock_t datatype ------------------------- */
-
-/* --------------------- gl_recursive_lock_t datatype --------------------- */
-
-/* -------------------------- gl_once_t datatype -------------------------- */
-
-static void
-glthread_once_call (void *arg)
-{
- void (**gl_once_temp_addr) (void) = (void (**) (void)) arg;
- void (*initfunction) (void) = *gl_once_temp_addr;
- initfunction ();
-}
-
-int
-glthread_once_multithreaded (pth_once_t *once_control, void (*initfunction) (void))
-{
- void (*temp) (void) = initfunction;
- return (!pth_once (once_control, glthread_once_call, &temp) ? errno : 0);
-}
-
-int
-glthread_once_singlethreaded (pth_once_t *once_control)
-{
- /* We know that pth_once_t is an integer type. */
- if (*once_control == PTH_ONCE_INIT)
- {
- /* First time use of once_control. Invert the marker. */
- *once_control = ~ PTH_ONCE_INIT;
- return 1;
- }
- else
- return 0;
-}
-
-#endif
-
-/* ========================================================================= */
-
-#if USE_SOLARIS_THREADS
-
-/* Use the old Solaris threads library. */
-
-/* -------------------------- gl_lock_t datatype -------------------------- */
-
-/* ------------------------- gl_rwlock_t datatype ------------------------- */
-
-/* --------------------- gl_recursive_lock_t datatype --------------------- */
-
-int
-glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock)
-{
- int err;
-
- err = mutex_init (&lock->mutex, USYNC_THREAD, NULL);
- if (err != 0)
- return err;
- lock->owner = (thread_t) 0;
- lock->depth = 0;
- return 0;
-}
-
-int
-glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock)
-{
- thread_t self = thr_self ();
- if (lock->owner != self)
- {
- int err;
-
- err = mutex_lock (&lock->mutex);
- if (err != 0)
- return err;
- lock->owner = self;
- }
- if (++(lock->depth) == 0) /* wraparound? */
- {
- lock->depth--;
- return EAGAIN;
- }
- return 0;
-}
-
-int
-glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock)
-{
- if (lock->owner != thr_self ())
- return EPERM;
- if (lock->depth == 0)
- return EINVAL;
- if (--(lock->depth) == 0)
- {
- lock->owner = (thread_t) 0;
- return mutex_unlock (&lock->mutex);
- }
- else
- return 0;
-}
-
-int
-glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock)
-{
- if (lock->owner != (thread_t) 0)
- return EBUSY;
- return mutex_destroy (&lock->mutex);
-}
-
-/* -------------------------- gl_once_t datatype -------------------------- */
-
-int
-glthread_once_multithreaded (gl_once_t *once_control, void (*initfunction) (void))
-{
- if (!once_control->inited)
- {
- int err;
-
- /* Use the mutex to guarantee that if another thread is already calling
- the initfunction, this thread waits until it's finished. */
- err = mutex_lock (&once_control->mutex);
- if (err != 0)
- return err;
- if (!once_control->inited)
- {
- once_control->inited = 1;
- initfunction ();
- }
- return mutex_unlock (&once_control->mutex);
- }
- else
- return 0;
-}
-
-int
-glthread_once_singlethreaded (gl_once_t *once_control)
-{
- /* We know that gl_once_t contains an integer type. */
- if (!once_control->inited)
- {
- /* First time use of once_control. Invert the marker. */
- once_control->inited = ~ 0;
- return 1;
- }
- else
- return 0;
-}
-
-#endif
-
-/* ========================================================================= */
-
#if USE_WINDOWS_THREADS
-/* -------------------------- gl_lock_t datatype -------------------------- */
-
-void
-glthread_lock_init_func (gl_lock_t *lock)
-{
- InitializeCriticalSection (&lock->lock);
- lock->guard.done = 1;
-}
-
-int
-glthread_lock_lock_func (gl_lock_t *lock)
-{
- if (!lock->guard.done)
- {
- if (InterlockedIncrement (&lock->guard.started) == 0)
- /* This thread is the first one to need this lock. Initialize it. */
- glthread_lock_init (lock);
- else
- /* Yield the CPU while waiting for another thread to finish
- initializing this lock. */
- while (!lock->guard.done)
- Sleep (0);
- }
- EnterCriticalSection (&lock->lock);
- return 0;
-}
-
-int
-glthread_lock_unlock_func (gl_lock_t *lock)
-{
- if (!lock->guard.done)
- return EINVAL;
- LeaveCriticalSection (&lock->lock);
- return 0;
-}
-
-int
-glthread_lock_destroy_func (gl_lock_t *lock)
-{
- if (!lock->guard.done)
- return EINVAL;
- DeleteCriticalSection (&lock->lock);
- lock->guard.done = 0;
- return 0;
-}
-
-/* ------------------------- gl_rwlock_t datatype ------------------------- */
-
-/* In this file, the waitqueues are implemented as circular arrays. */
-#define gl_waitqueue_t gl_carray_waitqueue_t
-
-static void
-gl_waitqueue_init (gl_waitqueue_t *wq)
-{
- wq->array = NULL;
- wq->count = 0;
- wq->alloc = 0;
- wq->offset = 0;
-}
-
-/* Enqueues the current thread, represented by an event, in a wait queue.
- Returns INVALID_HANDLE_VALUE if an allocation failure occurs. */
-static HANDLE
-gl_waitqueue_add (gl_waitqueue_t *wq)
-{
- HANDLE event;
- unsigned int index;
-
- if (wq->count == wq->alloc)
- {
- unsigned int new_alloc = 2 * wq->alloc + 1;
- HANDLE *new_array =
- (HANDLE *) realloc (wq->array, new_alloc * sizeof (HANDLE));
- if (new_array == NULL)
- /* No more memory. */
- return INVALID_HANDLE_VALUE;
- /* Now is a good opportunity to rotate the array so that its contents
- starts at offset 0. */
- if (wq->offset > 0)
- {
- unsigned int old_count = wq->count;
- unsigned int old_alloc = wq->alloc;
- unsigned int old_offset = wq->offset;
- unsigned int i;
- if (old_offset + old_count > old_alloc)
- {
- unsigned int limit = old_offset + old_count - old_alloc;
- for (i = 0; i < limit; i++)
- new_array[old_alloc + i] = new_array[i];
- }
- for (i = 0; i < old_count; i++)
- new_array[i] = new_array[old_offset + i];
- wq->offset = 0;
- }
- wq->array = new_array;
- wq->alloc = new_alloc;
- }
- /* Whether the created event is a manual-reset one or an auto-reset one,
- does not matter, since we will wait on it only once. */
- event = CreateEvent (NULL, TRUE, FALSE, NULL);
- if (event == INVALID_HANDLE_VALUE)
- /* No way to allocate an event. */
- return INVALID_HANDLE_VALUE;
- index = wq->offset + wq->count;
- if (index >= wq->alloc)
- index -= wq->alloc;
- wq->array[index] = event;
- wq->count++;
- return event;
-}
-
-/* Notifies the first thread from a wait queue and dequeues it. */
-static void
-gl_waitqueue_notify_first (gl_waitqueue_t *wq)
-{
- SetEvent (wq->array[wq->offset + 0]);
- wq->offset++;
- wq->count--;
- if (wq->count == 0 || wq->offset == wq->alloc)
- wq->offset = 0;
-}
-
-/* Notifies all threads from a wait queue and dequeues them all. */
-static void
-gl_waitqueue_notify_all (gl_waitqueue_t *wq)
-{
- unsigned int i;
-
- for (i = 0; i < wq->count; i++)
- {
- unsigned int index = wq->offset + i;
- if (index >= wq->alloc)
- index -= wq->alloc;
- SetEvent (wq->array[index]);
- }
- wq->count = 0;
- wq->offset = 0;
-}
-
-void
-glthread_rwlock_init_func (gl_rwlock_t *lock)
-{
- InitializeCriticalSection (&lock->lock);
- gl_waitqueue_init (&lock->waiting_readers);
- gl_waitqueue_init (&lock->waiting_writers);
- lock->runcount = 0;
- lock->guard.done = 1;
-}
-
-int
-glthread_rwlock_rdlock_func (gl_rwlock_t *lock)
-{
- if (!lock->guard.done)
- {
- if (InterlockedIncrement (&lock->guard.started) == 0)
- /* This thread is the first one to need this lock. Initialize it. */
- glthread_rwlock_init (lock);
- else
- /* Yield the CPU while waiting for another thread to finish
- initializing this lock. */
- while (!lock->guard.done)
- Sleep (0);
- }
- EnterCriticalSection (&lock->lock);
- /* Test whether only readers are currently running, and whether the runcount
- field will not overflow. */
- if (!(lock->runcount + 1 > 0))
- {
- /* This thread has to wait for a while. Enqueue it among the
- waiting_readers. */
- HANDLE event = gl_waitqueue_add (&lock->waiting_readers);
- if (event != INVALID_HANDLE_VALUE)
- {
- DWORD result;
- LeaveCriticalSection (&lock->lock);
- /* Wait until another thread signals this event. */
- result = WaitForSingleObject (event, INFINITE);
- if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
- abort ();
- CloseHandle (event);
- /* The thread which signalled the event already did the bookkeeping:
- removed us from the waiting_readers, incremented lock->runcount. */
- if (!(lock->runcount > 0))
- abort ();
- return 0;
- }
- else
- {
- /* Allocation failure. Weird. */
- do
- {
- LeaveCriticalSection (&lock->lock);
- Sleep (1);
- EnterCriticalSection (&lock->lock);
- }
- while (!(lock->runcount + 1 > 0));
- }
- }
- lock->runcount++;
- LeaveCriticalSection (&lock->lock);
- return 0;
-}
-
-int
-glthread_rwlock_wrlock_func (gl_rwlock_t *lock)
-{
- if (!lock->guard.done)
- {
- if (InterlockedIncrement (&lock->guard.started) == 0)
- /* This thread is the first one to need this lock. Initialize it. */
- glthread_rwlock_init (lock);
- else
- /* Yield the CPU while waiting for another thread to finish
- initializing this lock. */
- while (!lock->guard.done)
- Sleep (0);
- }
- EnterCriticalSection (&lock->lock);
- /* Test whether no readers or writers are currently running. */
- if (!(lock->runcount == 0))
- {
- /* This thread has to wait for a while. Enqueue it among the
- waiting_writers. */
- HANDLE event = gl_waitqueue_add (&lock->waiting_writers);
- if (event != INVALID_HANDLE_VALUE)
- {
- DWORD result;
- LeaveCriticalSection (&lock->lock);
- /* Wait until another thread signals this event. */
- result = WaitForSingleObject (event, INFINITE);
- if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
- abort ();
- CloseHandle (event);
- /* The thread which signalled the event already did the bookkeeping:
- removed us from the waiting_writers, set lock->runcount = -1. */
- if (!(lock->runcount == -1))
- abort ();
- return 0;
- }
- else
- {
- /* Allocation failure. Weird. */
- do
- {
- LeaveCriticalSection (&lock->lock);
- Sleep (1);
- EnterCriticalSection (&lock->lock);
- }
- while (!(lock->runcount == 0));
- }
- }
- lock->runcount--; /* runcount becomes -1 */
- LeaveCriticalSection (&lock->lock);
- return 0;
-}
-
-int
-glthread_rwlock_unlock_func (gl_rwlock_t *lock)
-{
- if (!lock->guard.done)
- return EINVAL;
- EnterCriticalSection (&lock->lock);
- if (lock->runcount < 0)
- {
- /* Drop a writer lock. */
- if (!(lock->runcount == -1))
- abort ();
- lock->runcount = 0;
- }
- else
- {
- /* Drop a reader lock. */
- if (!(lock->runcount > 0))
- {
- LeaveCriticalSection (&lock->lock);
- return EPERM;
- }
- lock->runcount--;
- }
- if (lock->runcount == 0)
- {
- /* POSIX recommends that "write locks shall take precedence over read
- locks", to avoid "writer starvation". */
- if (lock->waiting_writers.count > 0)
- {
- /* Wake up one of the waiting writers. */
- lock->runcount--;
- gl_waitqueue_notify_first (&lock->waiting_writers);
- }
- else
- {
- /* Wake up all waiting readers. */
- lock->runcount += lock->waiting_readers.count;
- gl_waitqueue_notify_all (&lock->waiting_readers);
- }
- }
- LeaveCriticalSection (&lock->lock);
- return 0;
-}
-
-int
-glthread_rwlock_destroy_func (gl_rwlock_t *lock)
-{
- if (!lock->guard.done)
- return EINVAL;
- if (lock->runcount != 0)
- return EBUSY;
- DeleteCriticalSection (&lock->lock);
- if (lock->waiting_readers.array != NULL)
- free (lock->waiting_readers.array);
- if (lock->waiting_writers.array != NULL)
- free (lock->waiting_writers.array);
- lock->guard.done = 0;
- return 0;
-}
-
-/* --------------------- gl_recursive_lock_t datatype --------------------- */
-
-void
-glthread_recursive_lock_init_func (gl_recursive_lock_t *lock)
-{
- lock->owner = 0;
- lock->depth = 0;
- InitializeCriticalSection (&lock->lock);
- lock->guard.done = 1;
-}
-
-int
-glthread_recursive_lock_lock_func (gl_recursive_lock_t *lock)
-{
- if (!lock->guard.done)
- {
- if (InterlockedIncrement (&lock->guard.started) == 0)
- /* This thread is the first one to need this lock. Initialize it. */
- glthread_recursive_lock_init (lock);
- else
- /* Yield the CPU while waiting for another thread to finish
- initializing this lock. */
- while (!lock->guard.done)
- Sleep (0);
- }
- {
- DWORD self = GetCurrentThreadId ();
- if (lock->owner != self)
- {
- EnterCriticalSection (&lock->lock);
- lock->owner = self;
- }
- if (++(lock->depth) == 0) /* wraparound? */
- {
- lock->depth--;
- return EAGAIN;
- }
- }
- return 0;
-}
-
-int
-glthread_recursive_lock_unlock_func (gl_recursive_lock_t *lock)
-{
- if (lock->owner != GetCurrentThreadId ())
- return EPERM;
- if (lock->depth == 0)
- return EINVAL;
- if (--(lock->depth) == 0)
- {
- lock->owner = 0;
- LeaveCriticalSection (&lock->lock);
- }
- return 0;
-}
-
-int
-glthread_recursive_lock_destroy_func (gl_recursive_lock_t *lock)
-{
- if (lock->owner != 0)
- return EBUSY;
- DeleteCriticalSection (&lock->lock);
- lock->guard.done = 0;
- return 0;
-}
-
-/* -------------------------- gl_once_t datatype -------------------------- */
-
-void
-glthread_once_func (gl_once_t *once_control, void (*initfunction) (void))
-{
- if (once_control->inited <= 0)
- {
- if (InterlockedIncrement (&once_control->started) == 0)
- {
- /* This thread is the first one to come to this once_control. */
- InitializeCriticalSection (&once_control->lock);
- EnterCriticalSection (&once_control->lock);
- once_control->inited = 0;
- initfunction ();
- once_control->inited = 1;
- LeaveCriticalSection (&once_control->lock);
- }
- else
- {
- /* Undo last operation. */
- InterlockedDecrement (&once_control->started);
- /* Some other thread has already started the initialization.
- Yield the CPU while waiting for the other thread to finish
- initializing and taking the lock. */
- while (once_control->inited < 0)
- Sleep (0);
- if (once_control->inited <= 0)
- {
- /* Take the lock. This blocks until the other thread has
- finished calling the initfunction. */
- EnterCriticalSection (&once_control->lock);
- LeaveCriticalSection (&once_control->lock);
- if (!(once_control->inited > 0))
- abort ();
- }
- }
- }
-}
-
#endif
/* ========================================================================= */
projects / deliverable / binutils-gdb.git / blobdiff