129 lines
4.2 KiB
C
129 lines
4.2 KiB
C
/****************************************************************************
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* sched/semaphore/sem_destroy.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 <errno.h>
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#include "semaphore/semaphore.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxsem_destroy
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*
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* Description:
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* This function is used to destroy the un-named semaphore indicated by
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* 'sem'. Only a semaphore that was created using nxsem_init() may be
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* destroyed using nxsem_destroy(); the effect of calling nxsem_destroy()
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* with a named semaphore is undefined. The effect of subsequent use of
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* the semaphore sem is undefined until sem is re-initialized by another
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* call to nxsem_init().
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*
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* The effect of destroying a semaphore upon which other processes are
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* currently blocked is undefined.
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*
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* Input Parameters:
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* sem - Semaphore to be destroyed.
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*
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* Returned Value:
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* This is an internal OS interface and should not be used by applications.
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* It follows the NuttX internal error return policy: Zero (OK) is
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* returned on success. A negated errno value is returned on failure.
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*
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****************************************************************************/
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int nxsem_destroy(FAR sem_t *sem)
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{
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DEBUGASSERT(sem != NULL);
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/* There is really no particular action that we need
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* take to destroy a semaphore. We will just reset
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* the count to some reasonable value (0) and release
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* ownership.
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*
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* Check if other threads are waiting on the semaphore.
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* In this case, the behavior is undefined. We will:
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* leave the count unchanged but still return OK.
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*/
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if (sem->semcount >= 0)
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{
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sem->semcount = 1;
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}
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/* Release holders of the semaphore */
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nxsem_destroyholder(sem);
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return OK;
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}
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/****************************************************************************
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* Name: sem_destroy
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*
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* Description:
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* This function is used to destroy the un-named semaphore indicated by
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* 'sem'. Only a semaphore that was created using nxsem_init() may be
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* destroyed using sem_destroy(); the effect of calling sem_destroy() with
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* a named semaphore is undefined. The effect of subsequent use of the
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* semaphore sem is undefined until sem is re-initialized by another call
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* to nxsem_init().
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*
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* The effect of destroying a semaphore upon which other processes are
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* currently blocked is undefined.
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*
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* Input Parameters:
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* sem - Semaphore to be destroyed.
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*
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* Returned Value:
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* This function is a application interface. It returns zero (OK) if
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* successful. Otherwise, -1 (ERROR) is returned and the errno value is
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* set appropriately.
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*
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****************************************************************************/
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int sem_destroy (FAR sem_t *sem)
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{
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int ret;
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/* Assure a valid semaphore is specified */
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if (sem == NULL)
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{
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set_errno(EINVAL);
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return ERROR;
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}
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ret = nxsem_destroy(sem);
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if (ret < 0)
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{
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set_errno(-ret);
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ret = ERROR;
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}
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return ret;
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}
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