Condition variable

condition variables More...

Macros
#define	cndOne   ( false )
	notify one task
#define	cndAll   ( true )
	notify all tasks (broadcast)
#define	OS_CND(cnd)
	define and initialize a condition variable object
#define	static_CND(cnd)
	static alias of OS_CND()
#define	CND_INIT()
	create and initialize a condition variable object
#define	CND_CREATE()
	create and initialize a condition variable object
#define	CND_NEW   CND_CREATE
	alias of CND_CREATE()

Functions
void	cnd_init (cnd_t *cnd)
	initialize a condition variable object
void	cnd_reset (cnd_t *cnd)
	reset the condition variable object and wake up all waiting tasks with 'E_STOPPED' event value
void	cnd_kill (cnd_t *cnd)
	alias of cnd_reset()
int	cnd_waitFor (cnd_t *cnd, mtx_t *mtx, cnt_t delay)
	wait for given duration of time on the condition variable releasing the currently owned mutex, and finally lock the mutex again
int	cnd_waitUntil (cnd_t *cnd, mtx_t *mtx, cnt_t time)
	wait until given timepoint on the condition variable releasing the currently owned mutex, and finally lock the mutex again
int	cnd_wait (cnd_t *cnd, mtx_t *mtx)
	wait indefinitely on the condition variable releasing the currently owned mutex, and finally lock the mutex again
void	cnd_give (cnd_t *cnd, bool all)
	signal one or all tasks that are waiting on the condition variable
void	cnd_notifyOne (cnd_t *cnd)
	signal one task waiting on the condition variable
void	cnd_notifyAll (cnd_t *cnd)
	signal all tasks waiting on the condition variable

Detailed Description

condition variables

Macro Definition Documentation

OS_CND

#define OS_CND

(

cnd

)

Value:

cnd_t cnd[] = { _CND_INIT() }

define and initialize a condition variable object

Parameters

cnd	name of a pointer to condition variable object

static_CND

#define static_CND

(

cnd

)

Value:

static cnd_t cnd[] = { _CND_INIT() }

static alias of OS_CND()

CND_INIT

#define CND_INIT

(

)

Value:

_CND_INIT()

create and initialize a condition variable object

Returns

condition variable object

Note

use only in 'C' code

CND_CREATE

#define CND_CREATE

(

)

Value:

{ CND_INIT  () }

create and initialize a condition variable object

Returns

condition variable object as array (id)

Note

use only in 'C' code

Function Documentation

cnd_init()

void cnd_init

(

cnd_t *

cnd

)

initialize a condition variable object

Parameters

cnd	pointer to condition variable object

cnd_reset()

void cnd_reset

(

cnd_t *

cnd

)

reset the condition variable object and wake up all waiting tasks with 'E_STOPPED' event value

Parameters

cnd	pointer to condition variable object

Note

use only in thread mode

cnd_waitFor()

int cnd_waitFor	(	cnd_t *	cnd,
		mtx_t *	mtx,
		cnt_t	delay )

wait for given duration of time on the condition variable releasing the currently owned mutex, and finally lock the mutex again

Parameters

cnd	pointer to condition variable object
mtx	currently owned mutex
delay	duration of time (maximum number of ticks to wait on the condition variable object) IMMEDIATE: don't wait on the condition variable object INFINITE: wait indefinitely on the condition variable object

Return values

E_SUCCESS	condition variable object was successfully signalled; owned mutex was locked again
E_FAILURE	mutex object can't be unlocked
E_STOPPED	condition variable or mutex object was reseted
E_TIMEOUT	condition variable object was not signalled before the specified timeout expired; owned mutex was locked again

cnd_waitUntil()

int cnd_waitUntil	(	cnd_t *	cnd,
		mtx_t *	mtx,
		cnt_t	time )

wait until given timepoint on the condition variable releasing the currently owned mutex, and finally lock the mutex again

Parameters

cnd	pointer to condition variable object
mtx	currently owned mutex
time	timepoint value

Return values

E_SUCCESS	condition variable object was successfully signalled; owned mutex was locked again
E_FAILURE	mutex object can't be unlocked
E_STOPPED	condition variable or mutex object was reseted
E_TIMEOUT	condition variable object was not signalled before the specified timeout expired; owned mutex was locked again

cnd_wait()

int cnd_wait ( cnd_t * cnd, mtx_t * mtx )

inline

wait indefinitely on the condition variable releasing the currently owned mutex, and finally lock the mutex again

Parameters

cnd	pointer to condition variable object
mtx	currently owned mutex

Return values

E_SUCCESS	condition variable object was successfully signalled; owned mutex was locked again
E_FAILURE	mutex object can't be unlocked
E_STOPPED	condition variable or mutex object was reseted

Note

use only in thread mode

cnd_give()

void cnd_give	(	cnd_t *	cnd,
		bool	all )

signal one or all tasks that are waiting on the condition variable

Parameters

cnd	pointer to condition variable object
all	signal receiver cndOne: notify one task that is waiting on the condition variable cndAll: notify all tasks that are waiting on the condition variable

cnd_notifyOne()

void cnd_notifyOne ( cnd_t * cnd )

inline

signal one task waiting on the condition variable

Parameters

cnd	pointer to condition variable object

Note

can be used in both thread and handler mode (for blockable interrupts)

cnd_notifyAll()

void cnd_notifyAll ( cnd_t * cnd )

inline

signal all tasks waiting on the condition variable

Parameters

cnd	pointer to condition variable object

Note

can be used in both thread and handler mode (for blockable interrupts)