2.3-InternetRadio/nutos/nut/include/sys/semaphore.h

/*
 * Copyright (C) 2000-2004 by ETH Zurich
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
 * 1. Redistributions of source code must retain the above copyright
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 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY ETH ZURICH AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ETH ZURICH
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/* sempahore.h - a nut/os implementation of semaphore functions
 *
 * 2004.05.06 Matthias Ringwald <matthias.ringwald@inf.ethz.ch>
 *
 */
/*
 * $Log$
 * Revision 1.5  2007/08/29 07:43:54  haraldkipp
 * Documentation updated and corrected.
 *
 * Revision 1.4  2005/08/02 17:46:49  haraldkipp
 * Major API documentation update.
 *
 * Revision 1.3  2004/06/02 16:43:36  olereinhardt
 * fixed bug (integer overflow) in semaphore implementation
 *
 * Revision 1.2  2004/05/18 18:38:14  drsung
 * Added $Log keyword for CVS and avoid multiple inclusion of header file.
 *
 */

#ifndef _SYS_SEMAPHORE_H
#define _SYS_SEMAPHORE_H

#include <compiler.h>
#include <sys/types.h>
#include <sys/thread.h>

/*!
 * \addtogroup xgSemaphore
 */
/*@{*/

/*!
 * \brief Sempahore type.
 */
typedef struct _SEM SEM;

/*!
 * \struct _SEM semaphore.h sys/semaphore.h
 * \brief Semaphore.
 *
 */
struct _SEM {
    HANDLE qhp;           /*!< \brief Queue to wait, if semaphore is zero. */
    short value;          /*!< \brief semaphore value . */
};

extern void NutSemInit(SEM * sem, short value);
extern void NutSemWait(SEM * sem);
extern int NutSemTryWait(SEM * sem);
extern void NutSemPost(SEM * sem);
extern int NutSemDestroy(SEM * sem);

/*@}*/

#endif /* #ifndef _SYS_SEMAPHORE_H */