forked from Archive/PX4-Autopilot
127 lines
4.8 KiB
C
127 lines
4.8 KiB
C
/********************************************************************************
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* sched/pthread_once.c
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*
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* Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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 <stdbool.h>
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#include <pthread.h>
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#include <sched.h>
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#include <errno.h>
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#include <debug.h>
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/********************************************************************************
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* Pre-processor Definitions
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********************************************************************************/
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/********************************************************************************
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* Private Type Declarations
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********************************************************************************/
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/********************************************************************************
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* Global Variables
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********************************************************************************/
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/********************************************************************************
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* Private Variables
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********************************************************************************/
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/********************************************************************************
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* Private Function Prototypes
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********************************************************************************/
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/********************************************************************************
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* Public Functions
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********************************************************************************/
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/********************************************************************************
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* Function: pthread_once
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*
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* Description:
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* The first call to pthread_once() by any thread with a given once_control,
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* will call the init_routine with no arguments. Subsequent calls to
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* pthread_once() with the same once_control will have no effect. On return
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* from pthread_once(), init_routine will have completed.
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*
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* Parameters:
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* once_control - Determines if init_routine should be called. once_control
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* should be declared and intialized as follows:
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*
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* pthread_once_t once_control = PTHREAD_ONCE_INIT;
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*
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* PTHREAD_ONCE_INIT is defined in pthread.h
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* init_routine - The initialization routine that will be called once.
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*
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* Return Value:
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* 0 (OK) on success or EINVAL if either once_control or init_routine are invalid
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*
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* Assumptions:
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*
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********************************************************************************/
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int pthread_once(FAR pthread_once_t *once_control, CODE void (*init_routine)(void))
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{
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/* Sanity checks */
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if (once_control && init_routine)
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{
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/* Prohibit pre-emption while we test and set the once_control */
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sched_lock();
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if (!*once_control)
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{
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*once_control = true;
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/* Call the init_routine with pre-emption enabled. */
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sched_unlock();
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init_routine();
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return OK;
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}
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/* The init_routine has already been called. Restore pre-emption and return */
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sched_unlock();
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return OK;
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}
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/* One of the two arguments is NULL */
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return EINVAL;
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}
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