nuttx/libc/misc/lib_streamsem.c

78 lines
2.7 KiB
C

/****************************************************************************
* libc/misc/lib_streamsem.c
*
* Copyright (C) 2007, 2009, 2011, 2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <semaphore.h>
#include <errno.h>
#include <nuttx/semaphore.h>
#include <nuttx/fs/fs.h>
#include "libc.h"
/****************************************************************************
* Public Functions
****************************************************************************/
void stream_semtake(FAR struct streamlist *list)
{
int ret;
/* Take the semaphore (perhaps waiting) */
while ((ret = _SEM_WAIT(&list->sl_sem)) < 0)
{
/* The only case that an error should occr here is if
* the wait was awakened by a signal.
*/
DEBUGASSERT(_SEM_ERRNO(ret) == EINTR);
UNUSED(ret);
}
}
void stream_semgive(FAR struct streamlist *list)
{
(void)_SEM_POST(&list->sl_sem);
}