Blocking For a Specified Interval

Use pthread_cond_reltimedwait_np(3C) as you would use pthread_cond_timedwait() with one exception. pthread_cond_reltimedwait_np() takes a relative time interval rather than an absolute future time of day as the value of its last argument.

pthread_cond_reltimedwait_np Syntax

int pthread_cond_reltimedwait_np(pthread_cond_t *cv, 
           pthread_mutex_t *mp, 
          const struct timespec *reltime);

#include <pthread.h>
#include <time.h> 
pthread_cond_t cv; 
pthread_mutex_t mp; 
timestruct_t reltime; 
int ret; 

/* wait on condition variable */ 
ret = pthread_cond_reltimedwait_np(&cv, &mp, &reltime); 

pthread_cond_reltimedwait_np() always returns with the mutex locked and owned by the calling thread, even when pthread_cond_reltimedwait_np() is returning an error. The pthread_cond_reltimedwait_np() function blocks until the condition is signaled or until the time interval specified by the last argument has elapsed.

pthread_cond_reltimedwait_np() is also a cancellation point.

pthread_cond_reltimedwait_np Return Values

pthread_cond_reltimedwait_np() returns zero after completing successfully. Any other return value indicates that an error occurred. When either of the following conditions occurs, the function fails and returns the corresponding value.

EINVAL

Description:

The value specified by reltime is invalid.

ETIMEDOUT

Description:

The time interval specified by reltime has passed.