Multithreaded Programming Guide

Initialize a Condition Variable

Use cond_init(3C) to initialize the condition variable pointed to by cv.

cond_init Syntax

#include <thread.h>

int cond_init(cond_t *cv, int type, int arg);

The type can be one of the following values:

Condition variables can also be initialized by allocation in zeroed memory, in which case a type of USYNC_THREAD is assumed.

Multiple threads must not initialize the same condition variable simultaneously. A condition variable must not be reinitialized while other threads might be using the condition variable.

For POSIX threads, see pthread_condattr_init Syntax .

Condition Variables With Intraprocess Scope

#include <thread.h>

cond_t cv;
int ret;

/* to be used within this process only */
ret = cond_init(cv, USYNC_THREAD, 0); 

Condition Variables With Interprocess Scope

#include <thread.h>

cond_t cv;
int ret;

/* to be used among all processes */
ret = cond_init(&cv, USYNC_PROCESS, 0); 

cond_init Return Values

cond_init() returns 0 if successful. When any of the following conditions is detected, cond_init() fails and returns the corresponding value.



cv points to an illegal address.



type is not a recognized type.