126 lines
3.9 KiB
C
126 lines
3.9 KiB
C
/****************************************************************************
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* sched/pthread/pthread_condbroadcast.c
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*
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* Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <pthread.h>
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#include <sched.h>
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#include <errno.h>
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#include <debug.h>
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#include "pthread/pthread.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pthread_cond_broadcast
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*
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* Description:
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* A thread broadcast on a condition variable.
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*
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* Parameters:
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* None
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*
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* Return Value:
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* None
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*
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* Assumptions:
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*
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****************************************************************************/
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int pthread_cond_broadcast(FAR pthread_cond_t *cond)
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{
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int ret = OK;
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int sval;
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sdbg("cond=0x%p\n", cond);
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if (!cond)
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{
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ret = EINVAL;
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}
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else
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{
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/* Disable pre-emption until all of the waiting threads have been
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* restarted. This is necessary to assure that the sval behaves as
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* expected in the following while loop
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*/
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sched_lock();
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/* Get the current value of the semaphore */
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if (sem_getvalue((FAR sem_t *)&cond->sem, &sval) != OK)
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{
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ret = EINVAL;
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}
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else
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{
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/* Loop until all of the waiting threads have been restarted. */
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while (sval < 0)
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{
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/* If the value is less than zero (meaning that one or more
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* thread is waiting), then post the condition semaphore.
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* Only the highest priority waiting thread will get to execute
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*/
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ret = pthread_givesemaphore((FAR sem_t *)&cond->sem);
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/* Increment the semaphore count (as was done by the
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* above post).
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*/
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sval++;
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}
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}
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/* Now we can let the restarted threads run */
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sched_unlock();
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}
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sdbg("Returning %d\n", ret);
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return ret;
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}
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