.\" Copyright (c) 2016 The FreeBSD Foundation
.\"
.\" This documentation was written by
.\" Konstantin Belousov <kib@FreeBSD.org> under sponsorship
.\" from the FreeBSD Foundation.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd March 27, 2017
.Dt PTHREAD_MUTEX_CONSISTENT 3
.Os
.Sh NAME
.Nm pthread_mutex_consistent
.Nd mark state protected by robust mutex as consistent
.Sh LIBRARY
.Lb libpthread
.Sh SYNOPSIS
.In pthread.h
.Ft int
.Fn pthread_mutex_consistent "pthread_mutex_t *mutex"
.Sh DESCRIPTION
If the process containing the thread owning a robust mutex terminates
while holding the mutex, the mutex becomes inconsistent and the next thread
that acquires the mutex lock is notified of the state by the return value
.Er EOWNERDEAD .
In this case, the mutex does not become normally usable again until
the state is marked consistent.
.Pp
The
.Fn pthread_mutex_consistent ,
when called with the
.Fa mutex
argument, which points to the initialized robust mutex in an
inconsistent state, marks the by mutex as consistent again.
The consequent unlock of the mutex, by either
.Fn pthread_mutex_unlock
or other methods, allows other contenders to lock the mutex.
.Pp
If the mutex in the inconsistent state is not marked consistent
by the call to
.Fn pthread_mutex_consistent
before unlock,
further attempts to lock the
.Fa mutex
result in the
.Er ENOTRECOVERABLE
condition reported by the locking functions.
.Sh RETURN VALUES
If successful,
.Fn pthread_mutex_consistent
will return zero, otherwise an error number will be returned to
indicate the error.
.Sh ERRORS
The
.Fn pthread_mutex_lock
function will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The mutex pointed to by the
.Fa mutex
argument is not robust, or is not in the inconsistent state.
.El
.Sh SEE ALSO
.Xr pthread_mutex_init 3 ,
.Xr pthread_mutex_lock 3 ,
.Xr pthread_mutex_unlock 3 ,
.Xr pthread_mutexattr_setrobust 3
.Sh STANDARDS
The
.Fn pthread_mutex_lock
function conforms to
.St -susv4 .