sem.h

MANTIS是由科罗拉多大学开发的传感器网络嵌入式操作系统。 这是mantis的0.9.5版本的源码。

//  This file is part of MANTIS OS, Operating System
//  See http://mantis.cs.colorado.edu/
//
//  Copyright (C) 2003,2004,2005 University of Colorado, Boulder
//
//  This program is free software; you can redistribute it and/or
//  modify it under the terms of the mos license (see file LICENSE)

/** @file micro/include/sem.h
 * @brief Semphore routines for use on sensor nodes.
 * @author Brian Shucker
 * @date 02/05/2003
 */

#ifndef SEMAPHORE_H_
#define SEMAPHORE_H_

#include <inttypes.h>

#include "tlist.h"

/** @brief Succeeded in decrementing semaphore */
#define SEM_SUCCESS 0
/** @brief Failed in decrementing semaphore */
#define SEM_FAIL 1

/** @brief Semaphore data structure */
typedef struct {
   /** @brief Current semaphore count */
   int8_t val;
   /** @brief List of threads waiting on semaphore */
   tlist_t q;
} mos_sem_t;

/** @brief Init the semaphores with beginning value.
 * @param s Semaphore to init
 * @param value Value to give the semaphore
 */
void mos_sem_init(mos_sem_t *s, int value);
/** @brief Post the semaphore.
 * @param s Semaphore to post
 */
void mos_sem_post(mos_sem_t *s);
/** @brief Wake up a specific thread.
 * @param s Semaphore to post
  * @param thread Thread
 */
void mos_sem_select_post(mos_sem_t *s, uint16_t thread);

/** @brief Wait on a semaphore.
 * @param s Semaphore
 */
void mos_sem_wait(mos_sem_t *s);

/** @brief Test the semaphore and decrement if possible, otherwise return.
 * @param s Semaphore
 * @return SEM_SUCCESS, SEM_FAIL
 */
uint8_t mos_sem_try_wait(mos_sem_t *s);

#endif