127 lines
4.7 KiB
C
127 lines
4.7 KiB
C
/****************************************************************************
|
|
* sched/semaphore/sem_destroy.c
|
|
*
|
|
* Copyright (C) 2007-2009, 2011 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 <semaphore.h>
|
|
#include <errno.h>
|
|
|
|
#include "semaphore/semaphore.h"
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Type Declarations
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Global Variables
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Variables
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: sem_destroy
|
|
*
|
|
* Description:
|
|
* This function is used to destroy the un-named semaphore indicated by
|
|
* 'sem'. Only a semaphore that was created using sem_init() may be
|
|
* destroyed using sem_destroy(); the effect of calling sem_destroy() with
|
|
* a named semaphore is undefined. The effect of subsequent use of the
|
|
* semaphore sem is undefined until sem is re-initialized by another call
|
|
* to sem_init().
|
|
*
|
|
* The effect of destroying a semaphore upon which other processes are
|
|
* currently blocked is undefined.
|
|
*
|
|
* Parameters:
|
|
* sem - Semaphore to be destroyed.
|
|
*
|
|
* Return Value:
|
|
* 0 (OK), or -1 (ERROR) if unsuccessful.
|
|
*
|
|
* Assumptions:
|
|
*
|
|
****************************************************************************/
|
|
|
|
int sem_destroy (FAR sem_t *sem)
|
|
{
|
|
/* Assure a valid semaphore is specified */
|
|
|
|
if (sem)
|
|
{
|
|
/* There is really no particular action that we need
|
|
* take to destroy a semaphore. We will just reset
|
|
* the count to some reasonable value (1) and release
|
|
* ownership.
|
|
*
|
|
* Check if other threads are waiting on the semaphore.
|
|
* In this case, the behavior is undefined. We will:
|
|
* leave the count unchanged but still return OK.
|
|
*/
|
|
|
|
if (sem->semcount >= 0)
|
|
{
|
|
sem->semcount = 1;
|
|
}
|
|
|
|
/* Release holders of the semaphore */
|
|
|
|
sem_destroyholder(sem);
|
|
return OK;
|
|
}
|
|
else
|
|
{
|
|
set_errno(EINVAL);
|
|
return ERROR;
|
|
}
|
|
}
|