1.\" Copyright (c) 1997 Brian Cully <shmit@kublai.com> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the author nor the names of any co-contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.Dd August 7, 2019 29.Dt PTHREAD_COND_WAIT 3 30.Os 31.Sh NAME 32.Nm pthread_cond_wait 33.Nd wait on a condition variable 34.Sh LIBRARY 35.Lb libpthread 36.Sh SYNOPSIS 37.In pthread.h 38.Ft int 39.Fn pthread_cond_wait "pthread_cond_t *restrict cond" "pthread_mutex_t *restrict mutex" 40.Sh DESCRIPTION 41The 42.Fn pthread_cond_wait 43function atomically blocks the current thread waiting on the condition 44variable specified by 45.Fa cond , 46and releases the mutex specified by 47.Fa mutex . 48The waiting thread unblocks only after another thread calls 49.Xr pthread_cond_signal 3 , 50or 51.Xr pthread_cond_broadcast 3 52with the same condition variable, and the current thread reacquires the lock 53on 54.Fa mutex . 55.Sh RETURN VALUES 56If successful, the 57.Fn pthread_cond_wait 58function will return zero. 59Otherwise an error number will be returned to 60indicate the error. 61.Sh ERRORS 62The 63.Fn pthread_cond_wait 64function will fail if: 65.Bl -tag -width Er 66.It Bq Er EINVAL 67The value specified by 68.Fa cond 69or the value specified by 70.Fa mutex 71is invalid. 72.It Bq Er EPERM 73The specified 74.Fa mutex 75was not locked by the calling thread. 76.It Bq Er EOWNERDEAD 77The argument 78.Fa mutex 79points to a robust mutex and the process containing the previous owning 80thread terminated while holding the mutex lock. 81The lock was granted to the caller and it is up to the new owner 82to make the state consistent. 83.It Bq Er ENOTRECOVERABLE 84The state protected by the 85.Fa mutex 86is not recoverable. 87.El 88.Sh SEE ALSO 89.Xr pthread_cond_broadcast 3 , 90.Xr pthread_cond_destroy 3 , 91.Xr pthread_cond_init 3 , 92.Xr pthread_cond_signal 3 , 93.Xr pthread_cond_timedwait 3 , 94.Xr pthread_mutex_consistent 3 95.Sh STANDARDS 96The 97.Fn pthread_cond_wait 98function conforms to 99.St -p1003.1-96 . 100