posix_semaphore.c
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/*
* Copyright (C) 2013 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @{
*
* @file
*
* @author Christian Mehlis <mehlis@inf.fu-berlin.de>
* @author Martine Lenders <mlenders@inf.fu-berlin.de>
* @author René Kijewski <kijewski@inf.fu-berlin.de>
*/
#include <errno.h>
#include <inttypes.h>
#include "irq.h"
#include "sched.h"
#include "sema.h"
#include "timex.h"
#include "thread.h"
#include "xtimer.h"
#define ENABLE_DEBUG (0)
#include "debug.h"
#include "semaphore.h"
int sem_timedwait(sem_t *sem, const struct timespec *abstime)
{
uint64_t timeout = (((uint64_t)abstime->tv_sec) * SEC_IN_USEC) +
(abstime->tv_nsec / USEC_IN_NS);
uint64_t now = xtimer_now_usec64();
if (now > timeout) {
errno = ETIMEDOUT;
return -1;
}
timeout = timeout - now;
int res = sema_wait_timed((sema_t *)sem, timeout);
if (res < 0) {
errno = -res;
return -1;
}
return 0;
}
int sem_trywait(sem_t *sem)
{
unsigned int old_state, value;
int result;
if (sem == NULL) {
errno = EINVAL;
return -1;
}
old_state = irq_disable();
value = sem->value;
if (value == 0) {
errno = EAGAIN;
result = -1;
}
else {
result = 0;
sem->value = value - 1;
}
irq_restore(old_state);
return result;
}
/** @} */