_lwp_cond_reltimedwait man page on SmartOS

Man page or keyword search:  
man Server   16655 pages
apropos Keyword Search (all sections)
Output format
SmartOS logo
[printable version]

_LWP_COND_WAIT(2)					     _LWP_COND_WAIT(2)

NAME
       _lwp_cond_wait, _lwp_cond_timedwait, _lwp_cond_reltimedwait - wait on a
       condition variable

SYNOPSIS
       #include <sys/lwp.h>

       int _lwp_cond_wait(lwp_cond_t *cvp, lwp_mutex_t *mp);

       int _lwp_cond_timedwait(lwp_cond_t *cvp, lwp_mutex_t *mp,
	    timestruc_t *abstime);

       int _lwp_cond_reltimedwait(lwp_cond_t *cvp, lwp_mutex_t *mp,
	    timestruc_t *reltime);

DESCRIPTION
       These functions are used to wait for the occurrence of a condition rep‐
       resented	 by an LWP condition variable. LWP condition variables must be
       initialized to 0 before use.

       The _lwp_cond_wait() function atomically releases the LWP mutex pointed
       to by mp and causes the calling LWP to block on the LWP condition vari‐
       able  pointed  to  by  cvp.  The	 blocked  LWP  may  be	 awakened   by
       _lwp_cond_signal(2),  _lwp_cond_broadcast(2),  or  when	interrupted by
       delivery of a signal. Any change in value  of  a	 condition  associated
       with  the  condition  variable  cannot  be  inferred  by	 the return of
       _lwp_cond_wait() and any such condition must be re-evaluated.

       The _lwp_cond_timedwait()  function  is	similar	 to  _lwp_cond_wait(),
       except  that the calling LWP will not block past the time of day speci‐
       fied by abstime. If the time  of	 day  becomes  greater	than  abstime,
       _lwp_cond_timedwait() returns with the error code ETIME.

       The  _lwp_cond_reltimedwait()  function is similar to _lwp_cond_wait(),
       except that the calling LWP will not block past the relative time spec‐
       ified  by reltime. If the time of day becomes greater than the starting
       time of day plus reltime,  _lwp_cond_reltimedwait()  returns  with  the
       error code ETIME.

       The  _lwp_cond_wait(),  _lwp_cond_timedwait(),  and _lwp_cond_reltimed‐
       wait() functions always return with the mutex locked and owned  by  the
       calling lightweight process.

RETURN VALUES
       Upon  successful	 completion, 0 is returned. A non-zero value indicates
       an error.

ERRORS
       If any of the  following	 conditions  are  detected,  _lwp_cond_wait(),
       _lwp_cond_timedwait(), and _lwp_cond_reltimedwait() fail and return the
       corresponding value:

       EINVAL
		 The cvp argument points to an invalid LWP condition  variable
		 or the mp argument points to an invalid LWP mutex.

       EFAULT
		 The  mp,  cvp,	 or  abstime  argument	points	to  an illegal
		 address.

       If  any	of   the   following   conditions   occur,   _lwp_cond_wait(),
       _lwp_cond_timedwait(), and _lwp_cond_reltimedwait() fail and return the
       corresponding value:

       EINTR
		The call was interrupted by a signal or fork(2).

       If any of the following	conditions  occur,  _lwp_cond_timedwait()  and
       _lwp_cond_reltimedwait() fail and return the corresponding value:

       ETIME
		The time specified inabstime or reltime has passed.

EXAMPLES
       Example 1 Use the _lwp_cond_wait() function in a loop testing some con‐
       dition.

       The _lwp_cond_wait() function is normally used in a loop	 testing  some
       condition, as follows:

	 lwp_mutex_t m;
	 lwp_cond_t cv;
	 int cond;
	 (void) _lwp_mutex_lock(&m);
	 while (cond == FALSE) {
		 (void) _lwp_cond_wait(&cv, &m);
	 }
	 (void) _lwp_mutex_unlock(&m);

       Example 2 Use the _lwp_cond_timedwait() function in a loop testing some
       condition.

       The _lwp_cond_timedwait() function is also  normally  used  in  a  loop
       testing some condition. It uses an absolute timeout value as follows:

	 timestruc_t to;
	 lwp_mutex_t m;
	 lwp_cond_t cv;
	 int cond, err;
	 (void) _lwp_mutex_lock(&m);
	 to.tv_sec = time(NULL) + TIMEOUT;
	 to.tv_nsec = 0;
	 while (cond == FALSE) {
		 err = _lwp_cond_timedwait(&cv, &m, &to);
		 if (err == ETIME) {
			 /* timeout, do something */
			 break;
		 SENDwhom}
	 }
	 (void) _lwp_mutex_unlock(&m);

       This  example  sets  a  bound  on  the  total wait time even though the
       _lwp_cond_timedwait() may return several times  due  to	the  condition
       being signalled or the wait being interrupted.

       Example	3  Use the _lwp_cond_reltimedwait() function in a loop testing
       some condition.

       The _lwp_cond_reltimedwait() function is also normally used in  a  loop
       testing some condition. It uses a relative timeout value as follows:

	 timestruc_t to;
	 lwp_mutex_t m;
	 lwp_cond_t cv;
	 int cond, err;
	 (void) _lwp_mutex_lock(&m);
	 while (cond == FALSE) {
		 to.tv_sec = TIMEOUT;
		 to.tv_nsec = 0;
		 err = _lwp_cond_reltimedwait(&cv, &m, &to);
		 if (err == ETIME) {
			 /* timeout, do something */
			 break;
		 }
	 }
	 (void) _lwp_mutex_unlock(&m);

SEE ALSO
       _lwp_cond_broadcast(2),	      _lwp_cond_signal(2),	 _lwp_kill(2),
       _lwp_mutex_lock(2), fork(2), kill(2)

				 Apr 13, 2001		     _LWP_COND_WAIT(2)
[top]

List of man pages available for SmartOS

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net