Condition Variables APIs

Macros
#define	K_CONDVAR_DEFINE(name)
	Statically define and initialize a condition variable.

Functions
int	k_condvar_init (struct k_condvar *condvar)
	Initialize a condition variable.
int	k_condvar_signal (struct k_condvar *condvar)
	Signals one thread that is pending on the condition variable.
int	k_condvar_broadcast (struct k_condvar *condvar)
	Unblock all threads that are pending on the condition variable.
int	k_condvar_wait (struct k_condvar *condvar, struct k_mutex *mutex, k_timeout_t timeout)
	Waits on the condition variable releasing the mutex lock.

Detailed Description

Macro Definition Documentation

K_CONDVAR_DEFINE

#define K_CONDVAR_DEFINE

(

name

)

#include <zephyr/kernel.h>

Value:

        STRUCT_SECTION_ITERABLE(k_condvar, name) =                             \
                Z_CONDVAR_INITIALIZER(name)

Statically define and initialize a condition variable.

The condition variable can be accessed outside the module where it is defined using:

extern struct k_condvar <name>; 

Parameters

name	Name of the condition variable.

Function Documentation

k_condvar_broadcast()

int k_condvar_broadcast

(

struct k_condvar *

condvar

)

#include <zephyr/kernel.h>

Unblock all threads that are pending on the condition variable.

Parameters

condvar

pointer to a k_condvar structure

Returns

An integer with number of woken threads on success

k_condvar_init()

int k_condvar_init

(

struct k_condvar *

condvar

)

#include <zephyr/kernel.h>

Initialize a condition variable.

Parameters

condvar

pointer to a k_condvar structure

Return values

0	Condition variable created successfully

k_condvar_signal()

int k_condvar_signal

(

struct k_condvar *

condvar

)

#include <zephyr/kernel.h>

Signals one thread that is pending on the condition variable.

Parameters

condvar

pointer to a k_condvar structure

Return values

0	On success

k_condvar_wait()

int k_condvar_wait	(	struct k_condvar *	condvar,
		struct k_mutex *	mutex,
		k_timeout_t	timeout
	)

#include <zephyr/kernel.h>

Waits on the condition variable releasing the mutex lock.

Atomically releases the currently owned mutex, blocks the current thread waiting on the condition variable specified by condvar, and finally acquires the mutex again.

The waiting thread unblocks only after another thread calls k_condvar_signal, or k_condvar_broadcast with the same condition variable.

Parameters

condvar	pointer to a k_condvar structure
mutex	Address of the mutex.
timeout	Waiting period for the condition variable or one of the special values K_NO_WAIT and K_FOREVER.

Return values

0	On success
-EAGAIN	Waiting period timed out.