condvar.h File Reference

Header file of file condvar.c. More...

#include "mutex.h"
#include "tqueue.h"
#include "thread.h"

Go to the source code of this file.

Data Structures
struct	cond
Typedefs
typedef cond	cond_t
Functions
void	cond_init (cond_t *cvar)
	Initialize condition variable.
void	cond_destroy (cond_t *cvar)
	Destroys conditional variable.
void	cond_signal (cond_t *cvar)
	Unlock one of threads waiting on the condition variable.
void	cond_broadcast (cond_t *cvar)
	Unlock all of threads waiting on the condition variable.
void	cond_wait (cond_t *cvar, struct mutex *mtx)
	Suspend calling thread on a condition variable waiting for condition Atomically unlocks mutex and suspends calling thread on conditional variable after waking up locks mutex.
int	cond_wait_timeout (cond_t *cvar, mutex_t *mtx, const unsigned int usec)
	Atomically unlocks mutex and suspends calling thread at most on \ usec microseconds.

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Detailed Description

Header file of file condvar.c.

Conditional variables are implemented as a queue of threads vaiting for the condition, that allows to wakeup them on cond_wait and cond signal calls.

This file is based on Kalisto, Development Kernel copyrighted (c) to Distributed Systems Research Group MFF UK, Czech republic.

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Typedef Documentation

typedef struct cond cond_t

define conditional variable to usual notation with .._t

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Function Documentation

void cond_broadcast

(

cond_t *

cvar

)

Unlock all of threads waiting on the condition variable.

Parameters:

cvar

condition variable struct pointer

void cond_destroy

(

cond_t *

cvar

)

Destroys conditional variable.

Parameters:

cvar

condition variable struct pointer

void cond_init

(

cond_t *

cvar

)

Initialize condition variable.

Parameters:

cvar

condition variable struct pointer

void cond_signal

(

cond_t *

cvar

)

Unlock one of threads waiting on the condition variable.

Parameters:

cvar

condition variable struct pointer

void cond_wait	(	cond_t *	cvar,
		struct mutex *	mtx
	)

Suspend calling thread on a condition variable waiting for condition Atomically unlocks mutex and suspends calling thread on conditional variable after waking up locks mutex.

Parameters:

	cvar	condition variable pointer
	mtx	mutex pointer

int cond_wait_timeout	(	cond_t *	cvar,
		mutex_t *	mtx,
		const unsigned int	usec
	)

Atomically unlocks mutex and suspends calling thread at most on \ usec microseconds.

If 0 msec is wanted thread suspend is ommitted, but the thread yield one times before next mutex lock

Parameters:

	cvar	condition variable struct pointer
	mtx	mutex pointer
	usec	time limit to wait

Returns:

EOK on thread woken up durint the wanted time period, ETIMEDOUT else

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