/****************************************************************************
* lib/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
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*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <semaphore.h>
#include <errno.h>
#include "sem_internal.h"
/****************************************************************************
* 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
{
errno = -EINVAL;
return ERROR;
}
}
