개요

• 솔라나라에 설명된 어플리케이션에 대해 맨 페이지를 찾아 출력한다.
• MAN 페이지에 대한 설명은 윈디하나의 솔라나라: MAN 페이지을 참고하자.
• svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.

_lwp_cond_timedwait(2)

_lwp_cond_wait(2)                System Calls                _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 in abstime or reltime has passed.


EXAMPLES
       Example 1 Using _lwp_cond_wait()



       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 Using _lwp_cond_timedwait()



       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;
                 }
         }
         (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 Using _lwp_cond_reltimedwait()



       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)



Oracle Solaris 11.4               25 Sep 2020                _lwp_cond_wait(2)