diff options
Diffstat (limited to 'pthreads/src/ptw32_semwait.c')
| -rw-r--r-- | pthreads/src/ptw32_semwait.c | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/pthreads/src/ptw32_semwait.c b/pthreads/src/ptw32_semwait.c new file mode 100644 index 0000000..c3c4fd0 --- /dev/null +++ b/pthreads/src/ptw32_semwait.c @@ -0,0 +1,135 @@ +/* + * ptw32_semwait.c + * + * Description: + * This translation unit implements mutual exclusion (mutex) 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 + */ + +#if !defined(_UWIN) +/*# include <process.h> */ +#endif +#include "pthread.h" +#include "implement.h" + + +int +ptw32_semwait (sem_t * sem) + /* + * ------------------------------------------------------ + * DESCRIPTION + * This function waits on a POSIX semaphore. If the + * semaphore value is greater than zero, it decreases + * its value by one. If the semaphore value is zero, then + * the calling thread (or process) is blocked until it can + * successfully decrease the value. + * + * Unlike sem_wait(), this routine is non-cancelable. + * + * RESULTS + * 0 successfully decreased semaphore, + * -1 failed, error in errno. + * ERRNO + * EINVAL 'sem' is not a valid semaphore, + * ENOSYS semaphores are not supported, + * EINTR the function was interrupted by a signal, + * EDEADLK a deadlock condition was detected. + * + * ------------------------------------------------------ + */ +{ + int result = 0; + sem_t s = *sem; + + if (s == NULL) + { + result = EINVAL; + } + else + { + if ((result = pthread_mutex_lock (&s->lock)) == 0) + { + int v; + + /* See sem_destroy.c + */ + if (*sem == NULL) + { + (void) pthread_mutex_unlock (&s->lock); + errno = EINVAL; + return -1; + } + + v = --s->value; + (void) pthread_mutex_unlock (&s->lock); + + if (v < 0) + { + /* Must wait */ + if (WaitForSingleObject (s->sem, INFINITE) == WAIT_OBJECT_0) + { +#if defined(NEED_SEM) + if (pthread_mutex_lock (&s->lock) == 0) + { + if (*sem == NULL) + { + (void) pthread_mutex_unlock (&s->lock); + errno = EINVAL; + return -1; + } + + if (s->leftToUnblock > 0) + { + --s->leftToUnblock; + SetEvent(s->sem); + } + (void) pthread_mutex_unlock (&s->lock); + } +#endif + return 0; + } + } + else + { + return 0; + } + } + } + + if (result != 0) + { + errno = result; + return -1; + } + + return 0; + +} /* ptw32_semwait */ |