incubator-nuttx/sched/semaphore/sem_timedwait.c

111 lines
4.5 KiB
C

/****************************************************************************
* sched/semaphore/sem_timedwait.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <assert.h>
#include <nuttx/semaphore.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxsem_timedwait
*
* Description:
* This function will lock the semaphore referenced by sem as in the
* sem_wait() function. However, if the semaphore cannot be locked without
* waiting for another process or thread to unlock the semaphore by
* performing a sem_post() function, this wait will be terminated when the
* specified timeout expires.
*
* The timeout will expire when the absolute time specified by abstime
* passes, as measured by the clock on which timeouts are based (that is,
* when the value of that clock equals or exceeds abstime), or if the
* absolute time specified by abstime has already been passed at the
* time of the call.
*
* This is an internal OS interface. It is functionally equivalent to
* sem_wait except that:
*
* - It is not a cancellation point, and
* - It does not modify the errno value.
*
* Input Parameters:
* sem - Semaphore object
* abstime - The absolute time to wait until a timeout is declared.
*
* Returned Value:
* This is an internal OS interface and should not be used by applications.
* It follows the NuttX internal error return policy: Zero (OK) is
* returned on success. A negated errno value is returned on failure.
* That may be one of:
*
* EINVAL The sem argument does not refer to a valid semaphore. Or the
* thread would have blocked, and the abstime parameter specified
* a nanoseconds field value less than zero or greater than or
* equal to 1000 million.
* ETIMEDOUT The semaphore could not be locked before the specified timeout
* expired.
* EDEADLK A deadlock condition was detected.
* EINTR A signal interrupted this function.
*
****************************************************************************/
int nxsem_timedwait(FAR sem_t *sem, FAR const struct timespec *abstime)
{
return nxsem_clockwait(sem, CLOCK_REALTIME, abstime);
}
/****************************************************************************
* Name: nxsem_timedwait_uninterruptible
*
* Description:
* This function is wrapped version of nxsem_timedwait(), which is
* uninterruptible and convenient for use.
*
* Input Parameters:
* sem - Semaphore object
* abstime - The absolute time to wait until a timeout is declared.
*
* Returned Value:
* EINVAL The sem argument does not refer to a valid semaphore. Or the
* thread would have blocked, and the abstime parameter specified
* a nanoseconds field value less than zero or greater than or
* equal to 1000 million.
* ETIMEDOUT The semaphore could not be locked before the specified timeout
* expired.
* EDEADLK A deadlock condition was detected.
* ECANCELED May be returned if the thread is canceled while waiting.
*
****************************************************************************/
int nxsem_timedwait_uninterruptible(FAR sem_t *sem,
FAR const struct timespec *abstime)
{
return nxsem_clockwait_uninterruptible(sem, CLOCK_REALTIME, abstime);
}