1.\" Copyright (c) 1997 Brian Cully <shmit@kublai.com>
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28.\" $FreeBSD: src/share/man/man3/pthread_cond_wait.3,v 1.22 2007/10/22 10:08:00 ru Exp $
29.\" $DragonFly: src/lib/libc_r/man/pthread_cond_wait.3,v 1.2 2003/06/17 04:26:48 dillon Exp $
30.\"
31.Dd July 10, 2009
32.Dt PTHREAD_COND_WAIT 3
33.Os
34.Sh NAME
35.Nm pthread_cond_wait
36.Nd wait on a condition variable
37.Sh LIBRARY
38.Lb libpthread
39.Sh SYNOPSIS
40.In pthread.h
41.Ft int
42.Fn pthread_cond_wait "pthread_cond_t *cond" "pthread_mutex_t *mutex"
43.Sh DESCRIPTION
44The
45.Fn pthread_cond_wait
46function atomically blocks the current thread waiting on the condition
47variable specified by
48.Fa cond ,
49and releases the mutex specified by
50.Fa mutex .
51The waiting thread unblocks only after another thread calls
52.Xr pthread_cond_signal 3 ,
53or
54.Xr pthread_cond_broadcast 3
55with the same condition variable, and the current thread reacquires the lock
56on
57.Fa mutex .
58.Sh RETURN VALUES
59If successful, the
60.Fn pthread_cond_wait
61function will return zero.
62Otherwise an error number will be returned to
63indicate the error.
64.Sh ERRORS
65The
66.Fn pthread_cond_wait
67function will fail if:
68.Bl -tag -width Er
69.It Bq Er EINVAL
70The value specified by
71.Fa cond
72or the value specified by
73.Fa mutex
74is invalid.
75.\".It Bq Er EPERM
76.\"The specified
77.\".Fa mutex
78.\"was not locked by the calling thread.
79.El
80.Sh SEE ALSO
81.Xr pthread_cond_broadcast 3 ,
82.Xr pthread_cond_destroy 3 ,
83.Xr pthread_cond_init 3 ,
84.Xr pthread_cond_signal 3 ,
85.Xr pthread_cond_timedwait 3
86.Sh STANDARDS
87The
88.Fn pthread_cond_wait
89function conforms to
90.St -p1003.1-96 .
91