NAME    [Toc]    [Back]

       pthread_cond_signal  -  Wakes  at least one thread that is
       waiting on the specified condition variable

SYNOPSIS    [Toc]    [Back]

       #include <pthread.h>

       int pthread_cond_signal(
               pthread_cond_t *cond );

LIBRARY    [Toc]    [Back]

       DECthreads POSIX 1003.1c Library (libpthread.so)

STANDARDS    [Toc]    [Back]

       Interfaces documented on this reference  page  conform  to
       industry standards as follows:

       IEEE  Std  1003.1c-1995,  POSIX System Application Program
       Interface

PARAMETERS    [Toc]    [Back]

       Condition variable to be signaled.

DESCRIPTION    [Toc]    [Back]

       This routine unblocks at least one thread waiting  on  the
       specified  condition  variable cond.  Calling this routine
       implies that data guarded  by  the  associated  mutex  has
       changed,  thus it might be possible for one of the waiting
       threads to proceed.  In general, only one thread  will  be
       released.

       If no threads are waiting on the specified condition variable,
 this routine takes no action. The  signal  does  not
       propagate to the next condition variable wait.

       This  routine  should be called when any thread waiting on
       the specified condition variable might find its  predicate
       true, but only one thread should proceed. If more than one
       thread can proceed, or if any of the threads would not  be
       able  to  proceed,  then  you must use pthread_cond_broadcast(3).

       The scheduling policy determines which thread is awakened.
       For  policies SCHED_FIFO and SCHED_RR, a blocked thread is
       chosen in priority order, using first-in/first-out  (FIFO)
       within priorities.

       If  the calling thread holds the lock to the target condition
 variable's associated mutex while setting  the  variable's
    wait    predicate,    that   thread   can   call
       pthread_cond_signal(3) to signal the variable  even  after
       releasing  the  lock on that mutex. However, for more predictable
 scheduling behavior, call  pthread_cond_signal(3)
       before  releasing  the target condition variable's associated
 mutex.

RETURN VALUES    [Toc]    [Back]

       If an error condition  occurs,  this  routine  returns  an
       integer  value  indicating  the  type  of  error. Possible
       return values are as follows: Successful completion.   The
       value specified by cond is not a valid condition variable.

ERRORS    [Toc]    [Back]

       None

SEE ALSO    [Toc]    [Back]

       Functions:                      pthread_cond_broadcast(3),
       pthread_cond_destroy(3),             pthread_cond_init(3),
       pthread_cond_timedwait(3), pthread_cond_wait(3)

       Manuals: Guide to DECthreads and Programmer's Guide



                                           pthread_cond_signal(3)