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/*
* -------------------------------------------------------------
*
* 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)
*
* -------------------------------------------------------------
*
* --------------------------------------------------------------------------
*
* Pthreads4w - POSIX Threads Library for Win32
* Copyright(C) 1998 John E. Bossom
* Copyright(C) 1999-2018, Pthreads4w contributors
*
* Homepage: https://sourceforge.net/projects/pthreads4w/
*
* 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:
* https://sourceforge.net/p/pthreads4w/wiki/Contributors/
*
* This file is part of Pthreads4w.
*
* Pthreads4w is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Pthreads4w 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Pthreads4w. If not, see <http://www.gnu.org/licenses/>. *
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#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
*
* ------------------------------------------------------
*/
{
ptw32_mcs_local_node_t node;
int result = 0;
long waiters;
sem_t s = *sem;
ptw32_mcs_lock_acquire(&s->lock, &node);
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;
}
ptw32_mcs_lock_release(&node);
if (result != 0)
{
PTW32_SET_ERRNO(result);
return -1;
}
return 0;
}
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