sem_timedwait(3C)					   Standard C Library Functions 					 sem_timedwait(3C)

NAME

       sem_timedwait, sem_reltimedwait_np - lock a semaphore

SYNOPSIS

       #include <semaphore.h>
       #include <time.h>

       int sem_timedwait(sem_t *restrict sem,
	    const struct timespec *restrict abs_timeout);

       int sem_reltimedwait_np(sem_t *restrict sem,
	    const struct timespec *restrict rel_timeout);

DESCRIPTION

       The  sem_timedwait()  function  locks  the semaphore referenced by sem as in the sem_wait(3C) function. However, if the semaphore cannot be
       locked without waiting for another process or thread to unlock the semaphore by performing a sem_post(3C) function, this wait is terminated
       when the specified timeout expires.

       The  sem_reltimedwait_np()  function  is identical to the sem_timedwait() function, except that the timeout is specified as a relative time
       interval.

       For sem_timedwait(), the timeout expires when the absolute time specified by abs_timeout passes, as measured by	the  CLOCK_REALTIME  clock
       (that  is,  when  the value of that clock equals or exceeds abs_timeout), or if the absolute time specified by abs_timeout has already been
       passed at the time of the call.

       For sem_reltimedwait_np(), the timeout expires when the time interval specified by rel_timeout passes, as measured  by  the  CLOCK_REALTIME
       clock, or if the time interval specified by rel_timeout is negative at the time of the call.

       The  resolution	of  the  timeout  is  the  resolution of the CLOCK_REALTIME clock. The timespec data type is defined as a structure in the
       <time.h> header.

       Under no circumstance does the function fail with a timeout if the semaphore can be locked immediately. The  validity  of  the  abs_timeout
       need not be checked if the semaphore can be locked immediately.

RETURN VALUES

       The sem_timedwait() and sem_reltimedwait_np() functions return 0 if the calling process successfully performed the semaphore lock operation
       on the semaphore designated by sem. If the call was unsuccessful, the state of the semaphore is be unchanged and the  function  returns	-1
       and sets errno to indicate the error.

ERRORS

       The sem_timedwait() and sem_reltimedwait_np() functions will fail if:

       EINVAL	    The sem argument does not refer to a valid semaphore.

       EINVAL	    The  process  or  thread  would  have blocked, and the timeout parameter specified a nanoseconds field value less than zero or
		    greater than or equal to 1,000 million.

       ETIMEDOUT    The semaphore could not be locked before the specified timeout expired.

       The sem_timedwait() and sem_reltimedwait_np() functions may fail if:

       EDEADLK	  A deadlock condition was detected.

       EINTR	  A signal interrupted this function.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Commmitted		   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+
       |Standard		     |See below.		   |
       +-----------------------------+-----------------------------+

       For sem_timedwait(), see standards(5).

SEE ALSO

       semctl(2), semget(2), semop(2), time(2), sem_post(3C), sem_trywait(3C)sem_wait(3C), attributes(5), standards(5)

SunOS 5.11							    5 Feb 2008							 sem_timedwait(3C)