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145 lines
5.1 KiB
145 lines
5.1 KiB
/**************************************************************************** |
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* include/semaphore.h |
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* |
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* Copyright (C) 2007-2009, 2012-2013 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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#ifndef __INCLUDE_SEMAPHORE_H |
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#define __INCLUDE_SEMAPHORE_H |
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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 <stdint.h> |
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#include <limits.h> |
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#ifdef __cplusplus |
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#define EXTERN extern "C" |
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extern "C" { |
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#else |
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#define EXTERN extern |
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#endif |
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/**************************************************************************** |
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* Pre-processor Definitions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Public Type Declarations |
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****************************************************************************/ |
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/* This structure contains information about the holder of a semaphore */ |
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#ifdef CONFIG_PRIORITY_INHERITANCE |
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struct semholder_s |
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{ |
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#if CONFIG_SEM_PREALLOCHOLDERS > 0 |
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struct semholder_s *flink; /* Implements singly linked list */ |
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#endif |
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void *htcb; /* Holder TCB (actual type is _TCB) */ |
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int16_t counts; /* Number of counts owned by this holder */ |
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}; |
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#if CONFIG_SEM_PREALLOCHOLDERS > 0 |
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# define SEMHOLDER_INITIALIZER {NULL, NULL, 0} |
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#else |
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# define SEMHOLDER_INITIALIZER {NULL, 0} |
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#endif |
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#endif /* CONFIG_PRIORITY_INHERITANCE */ |
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/* This is the generic semaphore structure. */ |
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struct sem_s |
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{ |
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int16_t semcount; /* >0 -> Num counts available */ |
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/* <0 -> Num tasks waiting for semaphore */ |
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/* If priority inheritance is enabled, then we have to keep track of which |
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* tasks hold references to the semaphore. |
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*/ |
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#ifdef CONFIG_PRIORITY_INHERITANCE |
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# if CONFIG_SEM_PREALLOCHOLDERS > 0 |
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FAR struct semholder_s *hhead; /* List of holders of semaphore counts */ |
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# else |
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struct semholder_s holder; /* Single holder */ |
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# endif |
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#endif |
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}; |
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typedef struct sem_s sem_t; |
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/* Initializers */ |
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#ifdef CONFIG_PRIORITY_INHERITANCE |
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# if CONFIG_SEM_PREALLOCHOLDERS > 0 |
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# define SEM_INITIALIZER(c) {(c), NULL} /* semcount, hhead */ |
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# else |
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# define SEM_INITIALIZER(c) {(c), SEMHOLDER_INITIALIZER} /* semcount, holder */ |
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# endif |
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#else |
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# define SEM_INITIALIZER(c) {(c)} /* semcount */ |
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#endif |
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/**************************************************************************** |
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* Public Variables |
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****************************************************************************/ |
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/**************************************************************************** |
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* Public Function Prototypes |
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****************************************************************************/ |
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/* Forward references needed by some prototypes */ |
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struct timespec; /* Defined in time.h */ |
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/* Counting Semaphore Interfaces (based on POSIX APIs) */ |
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EXTERN int sem_init(FAR sem_t *sem, int pshared, unsigned int value); |
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EXTERN int sem_destroy(FAR sem_t *sem); |
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EXTERN FAR sem_t *sem_open(FAR const char *name, int oflag, ...); |
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EXTERN int sem_close(FAR sem_t *sem); |
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EXTERN int sem_unlink(FAR const char *name); |
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EXTERN int sem_wait(FAR sem_t *sem); |
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EXTERN int sem_timedwait(FAR sem_t *sem, |
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FAR const struct timespec *abstime); |
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EXTERN int sem_trywait(FAR sem_t *sem); |
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EXTERN int sem_post(FAR sem_t *sem); |
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EXTERN int sem_getvalue(FAR sem_t *sem, FAR int *sval); |
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#undef EXTERN |
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#ifdef __cplusplus |
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} |
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#endif |
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#endif /* __INCLUDE_SEMAPHORE_H */
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