/*
* pthread_cond_wait.c
*
* Description:
* This translation unit implements condition variables and their primitives.
*
*
* --------------------------------------------------------------------------
*
* 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
*
* -------------------------------------------------------------
* Algorithm:
* The algorithm used in this implementation is that developed by
* Alexander Terekhov in colaboration with Louis Thomas. The bulk
* of the discussion is recorded in the file README.CV, which contains
* several generations of both colaborators original algorithms. The final
* algorithm used here is the one referred to as
*
* Algorithm 8a / IMPL_SEM,UNBLOCK_STRATEGY == UNBLOCK_ALL
*
* presented below in pseudo-code as it appeared:
*
*
* given:
* semBlockLock - bin.semaphore
* semBlockQueue - semaphore
* mtxExternal - mutex or CS
* mtxUnblockLock - mutex or CS
* nWaitersGone - int
* nWaitersBlocked - int
* nWaitersToUnblock - int
*
* wait( timeout ) {
*
* [auto: register int result ] // error checking omitted
* [auto: register int nSignalsWasLeft ]
* [auto: register int nWaitersWasGone ]
*
* sem_wait( semBlockLock );
* nWaitersBlocked++;
* sem_post( semBlockLock );
*
* unlock( mtxExternal );
* bTimedOut = sem_wait( semBlockQueue,timeout );
*
* lock( mtxUnblockLock );
* if ( 0 != (nSignalsWasLeft = nWaitersToUnblock) ) {
* if ( bTimeout ) { // timeout (or canceled)
* if ( 0 != nWaitersBlocked ) {
* nWaitersBlocked--;
* }
* else {
* nWaitersGone++; // count spurious wakeups.
* }
* }
* if ( 0 == --nWaitersToUnblock ) {
* if ( 0 != nWaitersBlocked ) {
* sem_post( semBlockLock ); // open the gate.
* nSignalsWasLeft = 0; // do not open the gate
* // below again.
* }
* else if ( 0 != (nWaitersWasGone = nWaitersGone) ) {
* nWaitersGone = 0;
* }
* }
* }
* else if ( INT_MAX/2 == ++nWaitersGone ) { // timeout/canceled or
* // spurious semaphore :-)
* sem_wait( semBlockLock );
* nWaitersBlocked -= nWaitersGone; // something is going on here
* // - test of timeouts? :-)
* sem_post( semBlockLock );
* nWaitersGone = 0;
* }
* unlock( mtxUnblockLock );
*
* if ( 1 == nSignalsWasLeft ) {
* if ( 0 != nWaitersWasGone ) {
* // sem_adjust( semBlockQueue,-nWaitersWasGone );
* while ( nWaitersWasGone-- ) {
* sem_wait( semBlockQueue ); // better now than spurious later
* }
* } sem_post( semBlockLock ); // open the gate
* }
*
* lock( mtxExternal );
*
* return ( bTimedOut ) ? ETIMEOUT : 0;
* }
*
* signal(bAll) {
*
* [auto: register int result ]
* [auto: register int nSignalsToIssue]
*
* lock( mtxUnblockLock );
*
* if ( 0 != nWaitersToUnblock ) { // the gate is closed!!!
* if ( 0 == nWaitersBlocked ) { // NO-OP
* return unlock( mtxUnblockLock );
* }
* if (bAll) {
* nWaitersToUnblock += nSignalsToIssue=nWaitersBlocked;
* nWaitersBlocked = 0;
* }
* else {
* nSignalsToIssue = 1;
* nWaitersToUnblock++;
* nWaitersBlocked--;
* }
* }
* else if ( nWaitersBlocked > nWaitersGone ) { // HARMLESS RACE CONDITION!
* sem_wait( semBlockLock ); // close the gate
* if ( 0 != nWaitersGone ) {
* nWaitersBlocked -= nWaitersGone;
* nWaitersGone = 0;
* }
* if (bAll) {
* nSignalsToIssue = nWaitersToUnblock = nWaitersBlocked;
* nWaitersBlocked = 0;
* }
* else {
* nSignalsToIssue = nWaitersToUnblock = 1;
* nWaitersBlocked--;
* }
* }
* else { // NO-OP
* return unlock( mtxUnblockLock );
* }
*
* unlock( mtxUnblockLock );
* sem_post( semBlockQueue,nSignalsToIssue );
* return result;
* }
* -------------------------------------------------------------
*
* Algorithm 9 / IMPL_SEM,UNBLOCK_STRATEGY == UNBLOCK_ALL
*
* presented below in pseudo-code; basically 8a...
* ...BUT W/O "spurious wakes" prevention:
*
*
* given:
* semBlockLock - bin.semaphore
* semBlockQueue - semaphore
* mtxExternal - mutex or CS
* mtxUnblockLock - mutex or CS
* nWaitersGone - int
* nWaitersBlocked - int
* nWaitersToUnblock - int
*
* wait( timeout ) {
*
* [auto: register int result ] // error checking omitted
* [auto: register int nSignalsWasLeft ]
*
* sem_wait( semBlockLock );
* ++nWaitersBlocked;
* sem_post( semBlockLock );
*
* unlock( mtxExternal );
* bTimedOut = sem_wait( semBlockQueue,timeout );
*
* lock( mtxUnblockLock );
* if ( 0 != (nSignalsWasLeft = nWaitersToUnblock) ) {
* --nWaitersToUnblock;
* }
* else if ( INT_MAX/2 == ++nWaitersGone ) { // timeout/canceled or
* // spurious semaphore :-)
* sem_wait( semBlockLock );
* nWaitersBlocked -= nWaitersGone; // something is going on here
* // - test of timeouts? :-)
* sem_post( semBlockLock );
* nWaitersGone = 0;
* }
* unlock( mtxUnblockLock );
*
* if ( 1 == nSignalsWasLeft ) {
* sem_post( semBlockLock ); // open the gate
* }
*
* lock( mtxExternal );
*
* return ( bTimedOut ) ? ETIMEOUT : 0;
* }
*
* signal(bAll) {
*
* [auto: register int result ]
* [auto: register int nSignalsToIssue]
*
* lock( mtxUnblockLock );
*
* if ( 0 != nWaitersToUnblock ) { // the gate is closed!!!
* if ( 0 == nWaitersBlocked ) { // NO-OP
* return unlock( mtxUnblockLock );
* }
* if (bAll) {
* nWaitersToUnblock += nSignalsToIssue=nWaitersBlocked;
* nWaitersBlocked = 0;
* }
* else {
* nSignalsToIssue = 1;
* ++nWaitersToUnblock;
* --nWaitersBlocked;
* }
* }
* else if ( nWaitersBlocked > nWaitersGone ) { // HARMLESS RACE CONDITION!
* sem_wait( semBlockLock ); // close the gate
* if ( 0 != nWaitersGone ) {
* nWaitersBlocked -= nWaitersGone
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pthread.zip （444个子文件） 
libpthreadGCE2.a 88KB libpthreadGC2.a 88KB ANNOUNCE 14KB ANNOUNCE 14KB builddmc.bat 428B install.bat 76B README.BENCHTESTS 2KB Bmakefile 11KB Bmakefile 6KB README.Borland 3KB README.Borland 3KB BUGS 6KB BUGS 6KB pthread_cond_wait.c 17KB multiPCcaBetter.c 9KB benchtest2.c 9KB eyal1.c 9KB ptw32_InterlockedCompareExchange.c 8KB ptw32_threadStart.c 8KB create.c 8KB pthread_win32_attach_detach_np.c 8KB alertdrv.c 8KB pthread_cond_destroy.c 7KB stress1.c 7KB benchtest1.c 7KB benchlib.c 7KB pthread_cond_signal.c 7KB ptw32_callUserDestroyRoutines.c 7KB ptw32_MCS_lock.c 7KB sem_timedwait.c 6KB sched_get_priority_min.c 6KB sched_get_priority_max.c 6KB condvar9.c 6KB exception1.c 6KB pthread_cancel.c 6KB benchtest3.c 6KB condvar8.c 6KB condvar7.c 6KB cancel2.c 6KB once4.c 6KB pthread_mutexattr_settype.c 5KB cleanup1.c 5KB benchtest4.c 5KB condvar6.c 5KB cancel8.c 5KB tsd2.c 5KB condvar3_1.c 5KB cancel9.c 5KB signal.c 5KB sem_wait.c 5KB tsd1.c 5KB cancel7.c 5KB inherit1.c 5KB condvar3_2.c 5KB cleanup0.c 5KB cleanup.c 5KB pthread_mutex_timedlock.c 5KB rwlock8.c 5KB priority2.c 5KB pthread_delay_np.c 5KB exception3.c 5KB exit5.c 5KB cleanup3.c 5KB cancel3.c 5KB rwlock7.c 5KB priority1.c 5KB QueueUserAPCEx.c 5KB cleanup2.c 5KB cancel4.c 5KB cancel5.c 5KB sem_destroy.c 5KB exit4.c 5KB QueueUserAPCEx.c 5KB sem_init.c 5KB w32_CancelableWait.c 5KB pthread_setspecific.c 5KB benchtest5.c 5KB cancel1.c 5KB ptw32_reuse.c 5KB pthread_join.c 5KB cancel6a.c 4KB cancel6d.c 4KB condvar4.c 4KB pthread_detach.c 4KB pthread_cond_init.c 4KB condvar5.c 4KB pthread_key_delete.c 4KB ptw32_throw.c 4KB reuse2.c 4KB pthread_rwlock_destroy.c 4KB pthread_setcanceltype.c 4KB pthread_setcancelstate.c 4KB ptw32_mutex_check_need_init.c 4KB pthread_self.c 4KB pthread_mutex_destroy.c 4KB sem_post_multiple.c 4KB once3.c 4KB ptw32_tkAssocCreate.c 4KB condvar2_1.c 4KB pthread_timechange_handler_np.c 4KB共 444 条
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