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#ifndef CYGONCE_KERNEL_SEMA_HXX
#define CYGONCE_KERNEL_SEMA_HXX
//==========================================================================
//
// sema.hxx
//
// Semaphore class declarations
//
//==========================================================================
// ####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
//
// eCos 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 2 or (at your option) any later
// version.
//
// eCos 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 eCos; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// As a special exception, if other files instantiate templates or use
// macros or inline functions from this file, or you compile this file
// and link it with other works to produce a work based on this file,
// this file does not by itself cause the resulting work to be covered by
// the GNU General Public License. However the source code for this file
// must still be made available in accordance with section (3) of the GNU
// General Public License v2.
//
// This exception does not invalidate any other reasons why a work based
// on this file might be covered by the GNU General Public License.
// -------------------------------------------
// ####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s): nickg
// Contributors: nickg
// Date: 1997-09-09
// Purpose: Define Semaphore class interfaces
// Description: The classes defined here provide the APIs for binary
// and counting semaphores.
// Usage: #include <cyg/kernel/sema.hxx>
//
//
//####DESCRIPTIONEND####
//
//==========================================================================
#include <cyg/kernel/ktypes.h>
#include <cyg/infra/cyg_ass.h> // assertion macros
#include <cyg/kernel/thread.inl> // thread inlines
// -------------------------------------------------------------------------
// Binary semaphore. This has only two states: posted and not-posted.
class Cyg_Binary_Semaphore
{
cyg_bool state; // The binary semaphore state
Cyg_ThreadQueue queue; // Queue of waiting threads
public:
CYGDBG_DEFINE_CHECK_THIS
Cyg_Binary_Semaphore( // Constructor
cyg_bool init_state = false // Initial state value
);
~Cyg_Binary_Semaphore(); // Destructor
cyg_bool wait(); // Wait until state == true
#ifdef CYGFUN_KERNEL_THREADS_TIMER
cyg_bool wait( cyg_tick_count timeout );
#endif // Wait until state == true or timeout
cyg_bool trywait(); // Set state false if possible
void post(); // Increment count
cyg_bool posted(); // Get current state
};
// -------------------------------------------------------------------------
// Counting semaphore. This implements the usual counter based semaphore.
class Cyg_Counting_Semaphore
{
cyg_count32 count; // The semaphore count
Cyg_ThreadQueue queue; // Queue of waiting threads
public:
CYGDBG_DEFINE_CHECK_THIS
Cyg_Counting_Semaphore( // Constructor
cyg_count32 init_count = 0 // Initial count value
);
~Cyg_Counting_Semaphore(); // Destructor
cyg_bool wait(); // Wait until decrement
#ifdef CYGFUN_KERNEL_THREADS_TIMER
cyg_bool wait( cyg_tick_count timeout );
#endif // Wait until decrement or timeout
cyg_bool trywait(); // Try to decrement
void post(); // Increment count
cyg_count32 peek() const; // Get current count value
inline
cyg_bool waiting() // Is anyone waiting?
{
return !queue.empty();
}
};
// -------------------------------------------------------------------------
#endif // ifndef CYGONCE_KERNEL_SEMA_HXX
// EOF sema.hxx
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