/****************************************************************************
* sched/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_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* 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;
sdbg("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((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((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();
}
sdbg("Returning %d\n", ret);
return ret;
}
