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128 lines
4.8 KiB
128 lines
4.8 KiB
/******************************************************************************** |
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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 <gnutt@nuttx.org> |
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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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* Name: 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 |
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* 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, |
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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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