cond.h

/**
 * @file cond.h
 * @author Skand Hurkat
 * @copyright All rights reserved 2015
 *
 * This file defines conditional variables for concurrent execution
 *
 * @warning This file is offered AS IS and WITHOUT ANY WARRANTY, without
 * even the implied warranties of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.
 */

#ifndef __COND_H_INCLUDED__
#define __COND_H_INCLUDED__

#include "3140_concur.h"
#include "shared_structs.h"

/**
 * Initialises the conditional variable structure
 *
 * @param l ignored
 * @param c pointer to conditional variable to be initialised
 */
void c_init(lock_t* l, cond_t* c);

/**
 * wait until condition is true
 *
 * @param l pointer to lock/mutex for conditional variable
 * @param c pointer to conditional variable
 */
void c_wait(lock_t* l, cond_t* c);

/**
 * Check if processes are waiting on conditional variable
 *
 * @param l Pointer to lock/mutex. Not used, but mutex must be acquired
 * before calling to ensure atomicity
 * @param c pointer to conditional variable
 *
 * @return 0 if no processes waiting
 * @return 1 if processes waiting
 */
int c_waiting(lock_t* l, cond_t* c);

/**
 * Signal that condition is met
 *
 * @warning Will misbehave if no processes are waiting and is signalled
 * 
 * @param l pointer to lock (is released after signalling)
 * @param c pointer to conditional variable
 */
void c_signal(lock_t* l, cond_t* c);

#endif /* __LOCK_H_INCLUDED */