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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file chsem.h
* @brief Semaphores macros and structures.
*
* @addtogroup semaphores
* @{
*/
#ifndef _CHSEM_H_
#define _CHSEM_H_
#if CH_USE_SEMAPHORES || defined(__DOXYGEN__)
/**
* @brief Semaphore structure.
*/
typedef struct Semaphore {
ThreadsQueue s_queue; /**< @brief Queue of the threads sleeping
on this semaphore. */
cnt_t s_cnt; /**< @brief The semaphore counter. */
} Semaphore;
#ifdef __cplusplus
extern "C" {
#endif
void chSemInit(Semaphore *sp, cnt_t n);
void chSemReset(Semaphore *sp, cnt_t n);
void chSemResetI(Semaphore *sp, cnt_t n);
msg_t chSemWait(Semaphore *sp);
msg_t chSemWaitS(Semaphore *sp);
msg_t chSemWaitTimeout(Semaphore *sp, systime_t time);
msg_t chSemWaitTimeoutS(Semaphore *sp, systime_t time);
void chSemSignal(Semaphore *sp);
void chSemSignalI(Semaphore *sp);
#if CH_USE_SEMSW
msg_t chSemSignalWait(Semaphore *sps, Semaphore *spw);
#endif
#ifdef __cplusplus
}
#endif
/**
* @brief Data part of a static semaphore initializer.
* @details This macro should be used when statically initializing a semaphore
* that is part of a bigger structure.
*
* @param[in] name the name of the semaphore variable
* @param[in] n the counter initial value, this value must be
* non-negative
*/
#define _SEMAPHORE_DATA(name, n) {_THREADSQUEUE_DATA(name.s_queue), n}
/**
* @brief Static semaphore initializer.
* @details Statically initialized semaphores require no explicit
* initialization using @p chSemInit().
*
* @param[in] name the name of the semaphore variable
* @param[in] n the counter initial value, this value must be
* non-negative
*/
#define SEMAPHORE_DECL(name, n) Semaphore name = _SEMAPHORE_DATA(name, n)
/**
* @brief Decreases the semaphore counter.
* @details This macro can be used when the counter is known to be positive.
*
* @iclass
*/
#define chSemFastWaitI(sp) ((sp)->s_cnt--)
/**
* @brief Increases the semaphore counter.
* @details This macro can be used when the counter is known to be not
* negative.
*
* @iclass
*/
#define chSemFastSignalI(sp) ((sp)->s_cnt++)
/**
* @brief Returns the semaphore counter current value.
*
* @iclass
*/
#define chSemGetCounterI(sp) ((sp)->s_cnt)
#endif /* CH_USE_SEMAPHORES */
#endif /* _CHSEM_H_ */
/** @} */
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