px4-firmware/nuttx/sched/pthread_mutexinit.c

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/****************************************************************************
* sched/pthread_mutexinit.c
*
* Copyright (C) 2007-2009, 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 <stdint.h>
#include <pthread.h>
#include <errno.h>
#include <debug.h>
#include "pthread_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: pthread_mutex_init
*
* Description:
* Create a mutex
*
* Parameters:
* None
*
* Return Value:
* None
*
* Assumptions:
*
****************************************************************************/
int pthread_mutex_init(FAR pthread_mutex_t *mutex, FAR pthread_mutexattr_t *attr)
{
int pshared = 0;
#ifdef CONFIG_MUTEX_TYPES
uint8_t type = PTHREAD_MUTEX_DEFAULT;
#endif
int ret = OK;
int status;
sdbg("mutex=0x%p attr=0x%p\n", mutex, attr);
if (!mutex)
{
ret = EINVAL;
}
else
{
/* Were attributes specified? If so, use them */
if (attr)
{
pshared = attr->pshared;
#ifdef CONFIG_MUTEX_TYPES
type = attr->type;
#endif
}
/* Indicate that the semaphore is not held by any thread. */
mutex->pid = 0;
/* Initialize the mutex like a semaphore with initial count = 1 */
status = sem_init((sem_t*)&mutex->sem, pshared, 1);
if (status != OK)
{
ret = EINVAL;
}
/* Set up attributes unique to the mutex type */
#ifdef CONFIG_MUTEX_TYPES
mutex->type = type;
mutex->nlocks = 0;
#endif
}
sdbg("Returning %d\n", ret);
return ret;
}