nuttx/libs/libc/pthread/pthread_condinit.c

/****************************************************************************
 * libs/libc/pthread/pthread_condinit.c
 *
 *   Copyright (C) 2007-2009, 2016-2017 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 <pthread.h>
#include <semaphore.h>
#include <debug.h>
#include <errno.h>

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: pthread_cond_init
 *
 * Description:
 *   A thread can create condition variables.
 *
 * Input Parameters:
 *   None
 *
 * Returned Value:
 *   None
 *
 * Assumptions:
 *
 ****************************************************************************/

int pthread_cond_init(FAR pthread_cond_t *cond,
                      FAR const pthread_condattr_t *attr)
{
  int ret = OK;

  sinfo("cond=0x%p attr=0x%p\n", cond, attr);

  if (cond == NULL)
    {
      ret = EINVAL;
    }

  /* Initialize the semaphore contained in the condition structure with
   * initial count = 0
   */

  else if (sem_init(&cond->sem, 0, 0) != OK)
    {
      ret = get_errno();
    }
  else
    {
      /* The contained semaphore is used for signaling and, hence, should
       * not have priority inheritance enabled.
       */

      sem_setprotocol(&cond->sem, SEM_PRIO_NONE);

      cond->clockid = attr ? attr->clockid : CLOCK_REALTIME;
    }

  sinfo("Returning %d\n", ret);
  return ret;
}