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- /****************************************************************************
- * libs/libc/sem/sem_init.c
- *
- * Copyright (C) 2007-2009, 2011-2012, 2016-2017 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 <sys/types.h>
- #include <limits.h>
- #include <errno.h>
- #include <nuttx/semaphore.h>
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: nxsem_init
- *
- * Description:
- * This function initializes the UNNAMED semaphore sem. Following a
- * successful call to nxsem_init(), the semaphore may be used in subsequent
- * calls to nxsem_wait(), nxsem_post(), and nxsem_trywait(). The semaphore
- * remains usable until it is destroyed.
- *
- * Only sem itself may be used for performing synchronization. The result
- * of referring to copies of sem in calls to nxsem_wait(), nxsem_trywait(),
- * nxsem_post(), and nxsem_destroy() is undefined.
- *
- * Input Parameters:
- * sem - Semaphore to be initialized
- * pshared - Process sharing (not used)
- * value - Semaphore initialization value
- *
- * Returned Value:
- * This is an internal OS interface and should not be used by applications.
- * It follows the NuttX internal error return policy: Zero (OK) is
- * returned on success. A negated errno value is returned on failure.
- *
- ****************************************************************************/
- int nxsem_init(FAR sem_t *sem, int pshared, unsigned int value)
- {
- /* Verify that a semaphore was provided and the count is within the valid
- * range.
- */
- if (sem != NULL && value <= SEM_VALUE_MAX)
- {
- /* Initialize the semaphore count */
- sem->semcount = (int16_t)value;
- /* Initialize to support priority inheritance */
- #ifdef CONFIG_PRIORITY_INHERITANCE
- sem->flags = 0;
- # if CONFIG_SEM_PREALLOCHOLDERS > 0
- sem->hhead = NULL;
- # else
- sem->holder[0].htcb = NULL;
- sem->holder[0].counts = 0;
- sem->holder[1].htcb = NULL;
- sem->holder[1].counts = 0;
- # endif
- #endif
- return OK;
- }
- return -EINVAL;
- }
- /****************************************************************************
- * Name: sem_init
- *
- * Description:
- * This function initializes the UNNAMED semaphore sem. Following a
- * successful call to sem_init(), the semaphore may be used in subsequent
- * calls to sem_wait(), sem_post(), and sem_trywait(). The semaphore
- * remains usable until it is destroyed.
- *
- * Only sem itself may be used for performing synchronization. The result
- * of referring to copies of sem in calls to sem_wait(), sem_trywait(),
- * sem_post(), and sem_destroy() is undefined.
- *
- * Input Parameters:
- * sem - Semaphore to be initialized
- * pshared - Process sharing (not used)
- * value - Semaphore initialization value
- *
- * Returned Value:
- * This returns zero (OK) if successful. Otherwise, -1 (ERROR) is
- * returned and the errno value is set appropriately.
- *
- ****************************************************************************/
- int sem_init(FAR sem_t *sem, int pshared, unsigned int value)
- {
- int ret;
- ret = nxsem_init(sem, pshared, value);
- if (ret < 0)
- {
- set_errno(-ret);
- ret = ERROR;
- }
- return ret;
- }
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