williamr@2: /*
williamr@2: * Copyright (c) 2005-2009 Nokia Corporation and/or its subsidiary(-ies).
williamr@2: * All rights reserved.
williamr@2: * This component and the accompanying materials are made available
williamr@2: * under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members
williamr@2: * which accompanies this distribution, and is available
williamr@2: * at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".
williamr@2: *
williamr@2: * Initial Contributors:
williamr@2: * Nokia Corporation - initial contribution.
williamr@2: *
williamr@2: * Contributors:
williamr@2: *
williamr@2: * Description:
williamr@2: * Name        : semaphore.h
williamr@2: * Part of     : semaphore
williamr@2: * Interface   : POSIX, semaphores
williamr@2: * POSIX implementation of semaphores on Symbian
williamr@2: * Version     : 
williamr@2: * All rights reserved.
williamr@2: * Redistribution and use in source and binary forms, with or without 
williamr@2: * modification, are permitted provided that the following conditions are met:
williamr@2: * Redistributions of source code must retain the above copyright notice, this 
williamr@2: * list of conditions and the following disclaimer. 
williamr@2: * Redistributions in binary form must reproduce the above copyright notice, 
williamr@2: * this list of conditions and the following disclaimer in the documentation 
williamr@2: * and/or other materials provided with the distribution. 
williamr@2: * Neither the name of the <ORGANIZATION> nor the names of its contributors 
williamr@2: * may be used to endorse or promote products derived from this software 
williamr@2: * without specific prior written permission. 
williamr@2: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
williamr@2: * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
williamr@2: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
williamr@2: * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
williamr@2: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
williamr@2: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
williamr@2: * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
williamr@2: * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
williamr@2: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
williamr@2: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
williamr@2: *
williamr@2: */
williamr@2: 
williamr@2: 
williamr@2: 
williamr@2: #ifndef __SEMAPHORE_H__
williamr@2: #define __SEMAPHORE_H__
williamr@2: 
williamr@2: #include <sys/types.h>
williamr@2: 
williamr@2: #ifdef __cplusplus
williamr@2: extern "C"
williamr@2: {
williamr@2: #endif              /* __cplusplus */
williamr@2: 
williamr@2: /*Semaphores supported */
williamr@2: 
williamr@2: #define SEM_FAILED -1
williamr@2: typedef struct _sem_t* sem_t;
williamr@2: 
williamr@2: /*
williamr@2: This function initializes the semaphore object.
williamr@2: The semaphore count is set to the initial count value. 
williamr@2: */
williamr@2: IMPORT_C extern int sem_init (sem_t * sem, int pshared, unsigned int value);
williamr@2: 
williamr@2: /*
williamr@2: This function destroys the semaphore  object. 
williamr@2: */
williamr@2: IMPORT_C extern int  sem_destroy (sem_t* sem);
williamr@2: 
williamr@2: /*
williamr@2: This function atomically decrements sem's count if it is greater than 0 and returns immediately,
williamr@2: or it returns immediately with a return code of -1 after having set errno to EAGAIN. 
williamr@2: sem_trywait never blocks.
williamr@2: */
williamr@2: IMPORT_C extern int sem_trywait (sem_t* sem);
williamr@2: 
williamr@2: /*
williamr@2: This function atomically decrements sem's count if it is greater than 0 and returns immediately
williamr@2: or it suspends the calling thread until it can resume following a call to sem_post or sem_post_multiple
williamr@2: */
williamr@2: IMPORT_C extern int sem_wait (sem_t* sem);
williamr@2: 
williamr@2: /*
williamr@2: This function atomically decrements sem's count if it is greater than 0 and returns immediately, or it 
williamr@2: suspends the calling thread. If timeout time lapses before the thread can be resumed because of a sem_post,
williamr@2: case, then sem_timedwait returns with a return code of -1 after having set errno to ETIMEDOUT. If the 
williamr@2: thread  can return without suspending then abstime parameter is not checked.
williamr@2: */
williamr@2: IMPORT_C extern int sem_timedwait (sem_t* sem, const struct timespec* abstime);
williamr@2: 
williamr@2: /*
williamr@2: The function increments (unlocks) the semaphore pointed to by sem .
williamr@2: If there are threads blocked on the semaphore when sem_post is called, the highest priority thread that has been blocked the longest on
williamr@2: the semaphore will be allowed to return from sem_wait .
williamr@2: If successful, the function returns zero; otherwise, it returns -1 and set errno to indicate the error.
williamr@2: */
williamr@2: IMPORT_C extern int sem_post (sem_t* sem);
williamr@2: 
williamr@2: /*
williamr@2: This function establish a connection between a named semaphore and a process
williamr@2: */
williamr@2: /* IMPORT_C extern sem_t* sem_open (const char* name,int oflag,mode_t mode, unsigned int value); */
williamr@2: 
williamr@2: /*
williamr@2: This function indicate that the calling process is finished using the named semaphore indicated by sem*/
williamr@2: /* IMPORT_C extern int sem_close (sem_t* sem); */
williamr@2: 
williamr@2: /*
williamr@2: This function cleans up resources associated with a system-wide semaphore.
williamr@2: */
williamr@2: /* IMPORT_C extern int sem_unlink (const char* name); */
williamr@2: 
williamr@2: /*
williamr@2: This function updates the location referenced by the sval argument with the value of the semaphore 
williamr@2: referenced by sem without affecting the state of the semaphore. 
williamr@2: The updated value represents an actual semaphore value that occurred at some unspecified time 
williamr@2: during the call, but it need not be the actual value of the semaphore when it is returned to 
williamr@2: the calling process. If sem is locked, then the object to which sval points shall either be set 
williamr@2: to zero or to a negative number whose absolute value represents the number of processes waiting
williamr@2: for the semaphore at some unspecified time during the call.
williamr@2: */
williamr@2: IMPORT_C extern int sem_getvalue (sem_t* sem, int* sval);
williamr@2: 
williamr@2: 
williamr@2: #ifdef __cplusplus
williamr@2: }               /* End of extern "C" */
williamr@2: #endif              /* __cplusplus */
williamr@2: 
williamr@2: #endif              /* __SEMAPHORE_H__ */