1.\" Copyright (c) 2004 Michael Telahun Makonnen 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.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.Dd August 17, 2018 26.Dt PTHREAD_RWLOCK_TIMEDWRLOCK 3 27.Os 28.Sh NAME 29.Nm pthread_rwlock_timedwrlock 30.Nd "acquire a read-write lock for writing or give up after a specified period" 31.Sh LIBRARY 32.Lb libpthread 33.Sh SYNOPSIS 34.In pthread.h 35.Ft int 36.Fn pthread_rwlock_timedwrlock "pthread_rwlock_t *restrict rwlock" "const struct timespec *restrict abs_timeout" 37.Sh DESCRIPTION 38This function acquires a write lock on the read-write lock 39.Fa rwlock . 40However, if the lock cannot be 41acquired without waiting for another thread to 42unlock the lock, 43this wait shall be terminated when 44.Fa abs_timeout 45expires. 46.Pp 47If the thread should be interrupted by a signal, 48the 49.Fn pthread_rwlock_timedwrlock 50function will be automatically restarted after the thread returns from 51the signal handler. 52.Pp 53The calling thread may deadlock if 54at the time the call is made it holds 55.Fa rwlock . 56The results are undefined if this function is called with 57an uninitialized read-write lock. 58.Sh IMPLEMENTATION NOTES 59To prevent writer starvation, writers are favored over readers. 60.Sh RETURN VALUES 61If successful, the 62.Fn pthread_rwlock_timedwrlock 63function will return zero. 64Otherwise, an error number will be returned to indicate the error. 65.Pp 66This function shall not return an error code of 67.Er EINTR . 68.Sh ERRORS 69The 70.Fn pthread_rwlock_timedwrlock 71function shall fail if: 72.Bl -tag -width Er 73.It Bq Er ETIMEDOUT 74The lock could not be acquired before the specified timeout expired. 75.El 76.Pp 77The 78.Fn pthread_rwlock_timedwrlock 79function may fail if: 80.Bl -tag -width Er 81.It Bq Er EDEADLK 82The calling thread already holds 83.Fa rwlock . 84.It Bq Er EINVAL 85The value specified by 86.Fa rwlock 87does not refer to an initialized read-write lock object, 88or the 89.Fa abs_timeout 90nanosecond value is less than zero or 91greater than or equal to 1 billion. 92.El 93.Sh SEE ALSO 94.Xr pthread_rwlock_init 3 , 95.Xr pthread_rwlock_timedrdlock 3 , 96.Xr pthread_rwlock_unlock 3 97.Sh STANDARDS 98The 99.Fn pthread_rwlock_timedwrlock 100function is expected to conform to 101.St -p1003.1-96 . 102.Sh HISTORY 103The 104.Fn pthread_rwlock_timedwrlock 105function first appeared in 106.Fx 5.2 . 107