text: /****************************************************************************
   * sched/pthread/pthread_condbroadcast.c
   *
   *   Copyright (C) 2007-2009 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 <sched.h>
  #include <errno.h>
  #include <debug.h>
  
  #include "pthread/pthread.h"
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: pthread_cond_broadcast
   *
   * Description:
   *    A thread broadcast on a condition variable.
   *
   * Parameters:
   *   None
   *
   * Return Value:
   *   None
   *
   * Assumptions:
   *
   ****************************************************************************/
  
  int pthread_cond_broadcast(FAR pthread_cond_t *cond)
  {
    int ret = OK;
    int sval;
  
    sinfo("cond=0x%p\n", cond);
  
    if (!cond)
      {
        ret = EINVAL;
      }
    else
      {
        /* Disable pre-emption until all of the waiting threads have been
         * restarted. This is necessary to assure that the sval behaves as
         * expected in the following while loop
         */
  
        sched_lock();
  
        /* Get the current value of the semaphore */
  
        if (sem_getvalue((FAR sem_t *)&cond->sem, &sval) != OK)
          {
            ret = EINVAL;
          }
        else
          {
            /* Loop until all of the waiting threads have been restarted. */
  
            while (sval < 0)
              {
                /* If the value is less than zero (meaning that one or more
                 * thread is waiting), then post the condition semaphore.
                 * Only the highest priority waiting thread will get to execute
                 */
  
                ret = pthread_givesemaphore((FAR sem_t *)&cond->sem);
  
                /* Increment the semaphore count (as was done by the
                 * above post).
                 */
  
                sval++;
              }
          }
  
        /* Now we can let the restarted threads run */
  
        sched_unlock();
      }
  
    sinfo("Returning %d\n", ret);
    return ret;
  }
  
  
  