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.Dd February 16, 2006
.Dt PTHREAD_COND_WAIT 3
.Os
.Sh NAME
.Nm pthread_cond_wait
.Nd wait on a condition variable
.Sh LIBRARY
.Lb libpthread
.Sh SYNOPSIS
.In pthread.h
.Ft int
.Fn pthread_cond_wait "pthread_cond_t *cond" "pthread_mutex_t *mutex"
.Sh DESCRIPTION
The
.Fn pthread_cond_wait
function atomically blocks the current thread waiting on the condition
variable specified by
.Fa cond ,
and releases the mutex specified by
.Fa mutex .
The waiting thread unblocks only after another thread calls
.Xr pthread_cond_signal 3 ,
or
.Xr pthread_cond_broadcast 3
with the same condition variable, and the current thread reacquires the lock
on
.Fa mutex .
.Sh RETURN VALUES
If successful, the
.Fn pthread_cond_wait
function will return zero.
Otherwise an error number will be returned to
indicate the error.
.Sh ERRORS
The
.Fn pthread_cond_wait
function will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The value specified by
.Fa cond
or the value specified by
.Fa mutex
is invalid.
.It Bq Er EPERM
The specified 
.Fa mutex 
was not locked by the calling thread.
.El
.Sh SEE ALSO
.Xr pthread_cond_broadcast 3 ,
.Xr pthread_cond_destroy 3 ,
.Xr pthread_cond_init 3 ,
.Xr pthread_cond_signal 3 ,
.Xr pthread_cond_timedwait 3
.Sh STANDARDS
The
.Fn pthread_cond_wait
function conforms to
.St -p1003.1-96 .