| /* |
| * ------------------------------------------------------------- |
| * |
| * Module: sem_post_multiple.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_post_multiple (sem_t * sem, int count) |
| /* |
| * ------------------------------------------------------ |
| * DOCPUBLIC |
| * This function posts multiple wakeups to a semaphore. |
| * |
| * PARAMETERS |
| * sem |
| * pointer to an instance of sem_t |
| * |
| * count |
| * counter, must be greater than zero. |
| * |
| * DESCRIPTION |
| * This function posts multiple wakeups to a semaphore. If there |
| * are waiting threads (or processes), n <= count are awakened; |
| * the semaphore value is incremented by count - n. |
| * |
| * RESULTS |
| * 0 successfully posted semaphore, |
| * -1 failed, error in errno |
| * ERRNO |
| * EINVAL 'sem' is not a valid semaphore |
| * or count is less than or equal to zero. |
| * ERANGE semaphore count is too big |
| * |
| * ------------------------------------------------------ |
| */ |
| { |
| int result = 0; |
| long waiters; |
| sem_t s = *sem; |
| |
| if (s == NULL || count <= 0) |
| { |
| result = EINVAL; |
| } |
| else if ((result = pthread_mutex_lock (&s->lock)) == 0) |
| { |
| /* See sem_destroy.c |
| */ |
| if (*sem == NULL) |
| { |
| (void) pthread_mutex_unlock (&s->lock); |
| result = EINVAL; |
| return -1; |
| } |
| |
| if (s->value <= (SEM_VALUE_MAX - count)) |
| { |
| waiters = -s->value; |
| s->value += count; |
| if (waiters > 0) |
| { |
| #if defined(NEED_SEM) |
| if (SetEvent(s->sem)) |
| { |
| waiters--; |
| s->leftToUnblock += count - 1; |
| if (s->leftToUnblock > waiters) |
| { |
| s->leftToUnblock = waiters; |
| } |
| } |
| #else |
| if (ReleaseSemaphore (s->sem, (waiters<=count)?waiters:count, 0)) |
| { |
| /* No action */ |
| } |
| #endif |
| else |
| { |
| s->value -= count; |
| result = EINVAL; |
| } |
| } |
| } |
| else |
| { |
| result = ERANGE; |
| } |
| (void) pthread_mutex_unlock (&s->lock); |
| } |
| |
| if (result != 0) |
| { |
| errno = result; |
| return -1; |
| } |
| |
| return 0; |
| |
| } /* sem_post_multiple */ |