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/********************************************************************************
* sched/pthread_once.c
*
* Copyright (C) 2007, 2009 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 <stdbool.h>
#include <pthread.h>
#include <sched.h>
#include <errno.h>
#include <debug.h>
/********************************************************************************
* Pre-processor Definitions
********************************************************************************/
/********************************************************************************
* Private Type Declarations
********************************************************************************/
/********************************************************************************
* Global Variables
********************************************************************************/
/********************************************************************************
* Private Variables
********************************************************************************/
/********************************************************************************
* Private Function Prototypes
********************************************************************************/
/********************************************************************************
* Public Functions
********************************************************************************/
/********************************************************************************
* Name: pthread_once
*
* Description:
* The first call to pthread_once() by any thread with a given once_control,
* will call the init_routine with no arguments. Subsequent calls to
* pthread_once() with the same once_control will have no effect. On return
* from pthread_once(), init_routine will have completed.
*
* Parameters:
* once_control - Determines if init_routine should be called. once_control
* should be declared and intialized as follows:
*
* pthread_once_t once_control = PTHREAD_ONCE_INIT;
*
* PTHREAD_ONCE_INIT is defined in pthread.h
* init_routine - The initialization routine that will be called once.
*
* Return Value:
* 0 (OK) on success or EINVAL if either once_control or init_routine are
* invalid
*
* Assumptions:
*
********************************************************************************/
int pthread_once(FAR pthread_once_t *once_control,
CODE void (*init_routine)(void))
{
/* Sanity checks */
if (once_control && init_routine)
{
/* Prohibit pre-emption while we test and set the once_control */
sched_lock();
if (!*once_control)
{
*once_control = true;
/* Call the init_routine with pre-emption enabled. */
sched_unlock();
init_routine();
return OK;
}
/* The init_routine has already been called. Restore pre-emption and return */
sched_unlock();
return OK;
}
/* One of the two arguments is NULL */
return EINVAL;
}
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