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-rw-r--r--pthread_once.c482
1 files changed, 241 insertions, 241 deletions
diff --git a/pthread_once.c b/pthread_once.c
index 9bcd975..62b412c 100644
--- a/pthread_once.c
+++ b/pthread_once.c
@@ -1,241 +1,241 @@
-/*
- * pthread_once.c
- *
- * Description:
- * This translation unit implements miscellaneous thread functions.
- *
- * --------------------------------------------------------------------------
- *
- * Pthreads-win32 - POSIX Threads Library for Win32
- * Copyright(C) 1998 John E. Bossom
- * Copyright(C) 1999,2005 Pthreads-win32 contributors
- *
- * Contact Email: rpj@callisto.canberra.edu.au
- *
- * The current list of contributors is contained
- * in the file CONTRIBUTORS included with the source
- * code distribution. The list can also be seen at the
- * following World Wide Web location:
- * http://sources.redhat.com/pthreads-win32/contributors.html
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library in the file COPYING.LIB;
- * if not, write to the Free Software Foundation, Inc.,
- * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
- */
-
-#include "pthread.h"
-#include "implement.h"
-
-
-static void
-ptw32_once_init_routine_cleanup(void * arg)
-{
- pthread_once_t * once_control = (pthread_once_t *) arg;
-
- (void) pthread_mutex_lock(&ptw32_once_control.mtx);
- once_control->done = PTW32_ONCE_CANCELLED;
- (void) PTW32_INTERLOCKED_EXCHANGE((LPLONG)&once_control->started, -1L);
- /*
- * Wake everyone up.
- *
- * Holding the mutex during the broadcast prevents threads being left
- * behind waiting.
- */
- (void) pthread_cond_broadcast(&ptw32_once_control.cond);
- (void) pthread_mutex_unlock(&ptw32_once_control.mtx);
-}
-
-
-int
-pthread_once (pthread_once_t * once_control, void (*init_routine) (void))
- /*
- * ------------------------------------------------------
- * DOCPUBLIC
- * If any thread in a process with a once_control parameter
- * makes a call to pthread_once(), the first call will summon
- * the init_routine(), but subsequent calls will not. The
- * once_control parameter determines whether the associated
- * initialization routine has been called. The init_routine()
- * is complete upon return of pthread_once().
- * This function guarantees that one and only one thread
- * executes the initialization routine, init_routine when
- * access is controlled by the pthread_once_t control
- * key.
- *
- * pthread_once() is not a cancelation point, but the init_routine
- * can be. If it's cancelled then the effect on the once_control is
- * as if pthread_once had never been entered.
- *
- * PARAMETERS
- * once_control
- * pointer to an instance of pthread_once_t
- *
- * init_routine
- * pointer to an initialization routine
- *
- *
- * DESCRIPTION
- * See above.
- *
- * RESULTS
- * 0 success,
- * EINVAL once_control or init_routine is NULL
- *
- * ------------------------------------------------------
- */
-{
- int result;
- LONG state;
- pthread_t self;
- HANDLE w32Thread = 0;
-
- if (once_control == NULL || init_routine == NULL)
- {
-
- result = EINVAL;
- goto FAIL0;
-
- }
- else
- {
- result = 0;
- }
-
- /*
- * Use a single global cond+mutex to manage access to all once_control objects.
- * Unlike a global mutex on it's own, the global cond+mutex allows faster
- * once_controls to overtake slower ones. Spurious wakeups may occur, but
- * can be tolerated.
- *
- * Since this is being introduced as a bug fix, the global cond+mtx also avoids
- * a change in the ABI, maintaining backwards compatibility.
- *
- * To maintain a separate mutex for each once_control object requires either
- * cleaning up the mutex (difficult to synchronise reliably), or leaving it
- * around forever. Since we can't make assumptions about how an application might
- * employ pthread_once objects, the later is considered to be unacceptable.
- *
- * once_control->done is now a multipurpose flag. It indicates either that
- * the init_routine has been completed, or the thread running it has been cancelled.
- *
- * Priority boosting is used to ensure that the init_routine thread is not
- * starved, by higher priority threads inside the while loop, before it can
- * clear the cancelled flag. The init_routine will be run at the thread's
- * normal base priority. Note that priority boosting is momentary, independent
- * for each once_control, and occurs only AFTER an init_routine cancellation.
- */
-
- while (!((state = InterlockedExchangeAdd((LPLONG)&once_control->done, 0L)) /* Full mem barrier read */
- & PTW32_ONCE_DONE))
- {
- /*
- * Keep a per thread record of the cancelled state for speed. If the
- * once_control state changes before we've finished with our local copy
- * then no harm is done - in fact, we need it to complete the full priority
- * boost transaction.
- */
- LONG cancelled = (state & PTW32_ONCE_CANCELLED);
-
- if (cancelled)
- {
- /* Boost priority momentarily */
- if (!w32Thread)
- {
- self = pthread_self();
- w32Thread = ((ptw32_thread_t *)self.p)->threadH;
- }
- /* Prevent pthread_setschedparam() changing our priority while we're boosted. */
- (void) pthread_mutex_lock(&((ptw32_thread_t *)self.p)->threadLock);
- SetThreadPriority(w32Thread, THREAD_PRIORITY_HIGHEST);
- }
-
- if (PTW32_INTERLOCKED_EXCHANGE((LPLONG) &once_control->started, 0L) == -1)
- {
- if (cancelled)
- {
- /* Reset cancelled state */
- (void) pthread_mutex_lock(&ptw32_once_control.mtx);
- once_control->done = PTW32_ONCE_CLEAR;
- (void) pthread_mutex_unlock(&ptw32_once_control.mtx);
-
- /*
- * Restore priority - any priority changes since the thread was created
- * will be applied only if they were made via POSIX (i.e. pthread_setschedparam).
- */
- SetThreadPriority(w32Thread, ((ptw32_thread_t *)self.p)->sched_priority);
- (void) pthread_mutex_unlock(&((ptw32_thread_t *)self.p)->threadLock);
- }
-
-#ifdef _MSC_VER
-#pragma inline_depth(0)
-#endif
-
- pthread_cleanup_push(ptw32_once_init_routine_cleanup, (void*) once_control);
- (*init_routine) ();
- pthread_cleanup_pop(0);
-
-#ifdef _MSC_VER
-#pragma inline_depth()
-#endif
-
- /*
- * Holding the mutex during the broadcast prevents threads being left
- * behind waiting.
- */
- (void) pthread_mutex_lock(&ptw32_once_control.mtx);
- once_control->done = PTW32_ONCE_DONE;
- (void) pthread_cond_broadcast(&ptw32_once_control.cond);
- (void) pthread_mutex_unlock(&ptw32_once_control.mtx);
- }
- else
- {
- int oldCancelState;
-
- if (cancelled)
- {
- /*
- * Restore priority - any priority changes since the thread was created
- * will be applied only if they were made via POSIX (i.e. pthread_setschedparam).
- */
- SetThreadPriority(w32Thread, ((ptw32_thread_t *)self.p)->sched_priority);
- (void) pthread_mutex_unlock(&((ptw32_thread_t *)self.p)->threadLock);
- }
-
- pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldCancelState);
- (void) pthread_mutex_lock(&ptw32_once_control.mtx);
- while (!once_control->done /* Neither DONE nor CANCELLED */
- || (!(once_control->done & PTW32_ONCE_DONE)
- && cancelled) /* Stop after one init_routine re-contest */)
- {
- cancelled = 0;
- (void) pthread_cond_wait(&ptw32_once_control.cond, &ptw32_once_control.mtx);
- }
- (void) pthread_mutex_unlock(&ptw32_once_control.mtx);
- pthread_setcancelstate(oldCancelState, NULL);
- }
- }
-
- /*
- * Fall through Intentionally
- */
-
- /*
- * ------------
- * Failure Code
- * ------------
- */
-FAIL0:
- return (result);
-
-} /* pthread_once */
+/*
+ * pthread_once.c
+ *
+ * Description:
+ * This translation unit implements miscellaneous thread functions.
+ *
+ * --------------------------------------------------------------------------
+ *
+ * Pthreads-win32 - POSIX Threads Library for Win32
+ * Copyright(C) 1998 John E. Bossom
+ * Copyright(C) 1999,2005 Pthreads-win32 contributors
+ *
+ * Contact Email: rpj@callisto.canberra.edu.au
+ *
+ * The current list of contributors is contained
+ * in the file CONTRIBUTORS included with the source
+ * code distribution. The list can also be seen at the
+ * following World Wide Web location:
+ * http://sources.redhat.com/pthreads-win32/contributors.html
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library in the file COPYING.LIB;
+ * if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include "pthread.h"
+#include "implement.h"
+
+
+static void
+ptw32_once_init_routine_cleanup(void * arg)
+{
+ pthread_once_t * once_control = (pthread_once_t *) arg;
+
+ (void) pthread_mutex_lock(&ptw32_once_control.mtx);
+ once_control->done = PTW32_ONCE_CANCELLED;
+ (void) PTW32_INTERLOCKED_EXCHANGE((LPLONG)&once_control->started, -1L);
+ /*
+ * Wake everyone up.
+ *
+ * Holding the mutex during the broadcast prevents threads being left
+ * behind waiting.
+ */
+ (void) pthread_cond_broadcast(&ptw32_once_control.cond);
+ (void) pthread_mutex_unlock(&ptw32_once_control.mtx);
+}
+
+
+int
+pthread_once (pthread_once_t * once_control, void (*init_routine) (void))
+ /*
+ * ------------------------------------------------------
+ * DOCPUBLIC
+ * If any thread in a process with a once_control parameter
+ * makes a call to pthread_once(), the first call will summon
+ * the init_routine(), but subsequent calls will not. The
+ * once_control parameter determines whether the associated
+ * initialization routine has been called. The init_routine()
+ * is complete upon return of pthread_once().
+ * This function guarantees that one and only one thread
+ * executes the initialization routine, init_routine when
+ * access is controlled by the pthread_once_t control
+ * key.
+ *
+ * pthread_once() is not a cancelation point, but the init_routine
+ * can be. If it's cancelled then the effect on the once_control is
+ * as if pthread_once had never been entered.
+ *
+ * PARAMETERS
+ * once_control
+ * pointer to an instance of pthread_once_t
+ *
+ * init_routine
+ * pointer to an initialization routine
+ *
+ *
+ * DESCRIPTION
+ * See above.
+ *
+ * RESULTS
+ * 0 success,
+ * EINVAL once_control or init_routine is NULL
+ *
+ * ------------------------------------------------------
+ */
+{
+ int result;
+ LONG state;
+ pthread_t self;
+ HANDLE w32Thread = 0;
+
+ if (once_control == NULL || init_routine == NULL)
+ {
+
+ result = EINVAL;
+ goto FAIL0;
+
+ }
+ else
+ {
+ result = 0;
+ }
+
+ /*
+ * Use a single global cond+mutex to manage access to all once_control objects.
+ * Unlike a global mutex on it's own, the global cond+mutex allows faster
+ * once_controls to overtake slower ones. Spurious wakeups may occur, but
+ * can be tolerated.
+ *
+ * Since this is being introduced as a bug fix, the global cond+mtx also avoids
+ * a change in the ABI, maintaining backwards compatibility.
+ *
+ * To maintain a separate mutex for each once_control object requires either
+ * cleaning up the mutex (difficult to synchronise reliably), or leaving it
+ * around forever. Since we can't make assumptions about how an application might
+ * employ pthread_once objects, the later is considered to be unacceptable.
+ *
+ * once_control->done is now a multipurpose flag. It indicates either that
+ * the init_routine has been completed, or the thread running it has been cancelled.
+ *
+ * Priority boosting is used to ensure that the init_routine thread is not
+ * starved, by higher priority threads inside the while loop, before it can
+ * clear the cancelled flag. The init_routine will be run at the thread's
+ * normal base priority. Note that priority boosting is momentary, independent
+ * for each once_control, and occurs only AFTER an init_routine cancellation.
+ */
+
+ while (!((state = InterlockedExchangeAdd((LPLONG)&once_control->done, 0L)) /* Full mem barrier read */
+ & PTW32_ONCE_DONE))
+ {
+ /*
+ * Keep a per thread record of the cancelled state for speed. If the
+ * once_control state changes before we've finished with our local copy
+ * then no harm is done - in fact, we need it to complete the full priority
+ * boost transaction.
+ */
+ LONG cancelled = (state & PTW32_ONCE_CANCELLED);
+
+ if (cancelled)
+ {
+ /* Boost priority momentarily */
+ if (!w32Thread)
+ {
+ self = pthread_self();
+ w32Thread = ((ptw32_thread_t *)self.p)->threadH;
+ }
+ /* Prevent pthread_setschedparam() changing our priority while we're boosted. */
+ (void) pthread_mutex_lock(&((ptw32_thread_t *)self.p)->threadLock);
+ SetThreadPriority(w32Thread, THREAD_PRIORITY_HIGHEST);
+ }
+
+ if (PTW32_INTERLOCKED_EXCHANGE((LPLONG) &once_control->started, 0L) == -1)
+ {
+ if (cancelled)
+ {
+ /* Reset cancelled state */
+ (void) pthread_mutex_lock(&ptw32_once_control.mtx);
+ once_control->done = PTW32_ONCE_CLEAR;
+ (void) pthread_mutex_unlock(&ptw32_once_control.mtx);
+
+ /*
+ * Restore priority - any priority changes since the thread was created
+ * will be applied only if they were made via POSIX (i.e. pthread_setschedparam).
+ */
+ SetThreadPriority(w32Thread, ((ptw32_thread_t *)self.p)->sched_priority);
+ (void) pthread_mutex_unlock(&((ptw32_thread_t *)self.p)->threadLock);
+ }
+
+#ifdef _MSC_VER
+#pragma inline_depth(0)
+#endif
+
+ pthread_cleanup_push(ptw32_once_init_routine_cleanup, (void*) once_control);
+ (*init_routine) ();
+ pthread_cleanup_pop(0);
+
+#ifdef _MSC_VER
+#pragma inline_depth()
+#endif
+
+ /*
+ * Holding the mutex during the broadcast prevents threads being left
+ * behind waiting.
+ */
+ (void) pthread_mutex_lock(&ptw32_once_control.mtx);
+ once_control->done = PTW32_ONCE_DONE;
+ (void) pthread_cond_broadcast(&ptw32_once_control.cond);
+ (void) pthread_mutex_unlock(&ptw32_once_control.mtx);
+ }
+ else
+ {
+ int oldCancelState;
+
+ if (cancelled)
+ {
+ /*
+ * Restore priority - any priority changes since the thread was created
+ * will be applied only if they were made via POSIX (i.e. pthread_setschedparam).
+ */
+ SetThreadPriority(w32Thread, ((ptw32_thread_t *)self.p)->sched_priority);
+ (void) pthread_mutex_unlock(&((ptw32_thread_t *)self.p)->threadLock);
+ }
+
+ pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldCancelState);
+ (void) pthread_mutex_lock(&ptw32_once_control.mtx);
+ while (!once_control->done /* Neither DONE nor CANCELLED */
+ || (!(once_control->done & PTW32_ONCE_DONE)
+ && cancelled) /* Stop after one init_routine re-contest */)
+ {
+ cancelled = 0;
+ (void) pthread_cond_wait(&ptw32_once_control.cond, &ptw32_once_control.mtx);
+ }
+ (void) pthread_mutex_unlock(&ptw32_once_control.mtx);
+ pthread_setcancelstate(oldCancelState, NULL);
+ }
+ }
+
+ /*
+ * Fall through Intentionally
+ */
+
+ /*
+ * ------------
+ * Failure Code
+ * ------------
+ */
+FAIL0:
+ return (result);
+
+} /* pthread_once */