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Diffstat (limited to 'pthreads/src/sem_destroy.c')
| -rw-r--r-- | pthreads/src/sem_destroy.c | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/pthreads/src/sem_destroy.c b/pthreads/src/sem_destroy.c new file mode 100644 index 0000000..6c98e80 --- /dev/null +++ b/pthreads/src/sem_destroy.c @@ -0,0 +1,144 @@ +/* + * ------------------------------------------------------------- + * + * Module: sem_destroy.c + * + * Purpose: + * Semaphores aren't actually part of the PThreads standard. + * They are defined by the POSIX Standard: + * + * POSIX 1003.1b-1993 (POSIX.1b) + * + * ------------------------------------------------------------- + * + * -------------------------------------------------------------------------- + * + * 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 "semaphore.h" +#include "implement.h" + + +int +sem_destroy (sem_t * sem) + /* + * ------------------------------------------------------ + * DOCPUBLIC + * This function destroys an unnamed semaphore. + * + * PARAMETERS + * sem + * pointer to an instance of sem_t + * + * DESCRIPTION + * This function destroys an unnamed semaphore. + * + * RESULTS + * 0 successfully destroyed semaphore, + * -1 failed, error in errno + * ERRNO + * EINVAL 'sem' is not a valid semaphore, + * ENOSYS semaphores are not supported, + * EBUSY threads (or processes) are currently + * blocked on 'sem' + * + * ------------------------------------------------------ + */ +{ + int result = 0; + sem_t s = NULL; + + if (sem == NULL || *sem == NULL) + { + result = EINVAL; + } + else + { + s = *sem; + + if ((result = pthread_mutex_lock (&s->lock)) == 0) + { + if (s->value < 0) + { + (void) pthread_mutex_unlock (&s->lock); + result = EBUSY; + } + else + { + /* There are no threads currently blocked on this semaphore. */ + + if (!CloseHandle (s->sem)) + { + (void) pthread_mutex_unlock (&s->lock); + result = EINVAL; + } + else + { + /* + * Invalidate the semaphore handle when we have the lock. + * Other sema operations should test this after acquiring the lock + * to check that the sema is still valid, i.e. before performing any + * operations. This may only be necessary before the sema op routine + * returns so that the routine can return EINVAL - e.g. if setting + * s->value to SEM_VALUE_MAX below does force a fall-through. + */ + *sem = NULL; + + /* Prevent anyone else actually waiting on or posting this sema. + */ + s->value = SEM_VALUE_MAX; + + (void) pthread_mutex_unlock (&s->lock); + + do + { + /* Give other threads a chance to run and exit any sema op + * routines. Due to the SEM_VALUE_MAX value, if sem_post or + * sem_wait were blocked by us they should fall through. + */ + Sleep(0); + } + while (pthread_mutex_destroy (&s->lock) == EBUSY); + } + } + } + } + + if (result != 0) + { + errno = result; + return -1; + } + + free (s); + + return 0; + +} /* sem_destroy */ |