2a339d9e3d
intention of the POSIX IEEE Std 1003.1TM-2008/Cor 1-2013. A robust mutex is guaranteed to be cleared by the system upon either thread or process owner termination while the mutex is held. The next mutex locker is then notified about inconsistent mutex state and can execute (or abandon) corrective actions. The patch mostly consists of small changes here and there, adding neccessary checks for the inconsistent and abandoned conditions into existing paths. Additionally, the thread exit handler was extended to iterate over the userspace-maintained list of owned robust mutexes, unlocking and marking as terminated each of them. The list of owned robust mutexes cannot be maintained atomically synchronous with the mutex lock state (it is possible in kernel, but is too expensive). Instead, for the duration of lock or unlock operation, the current mutex is remembered in a special slot that is also checked by the kernel at thread termination. Kernel must be aware about the per-thread location of the heads of robust mutex lists and the current active mutex slot. When a thread touches a robust mutex for the first time, a new umtx op syscall is issued which informs about location of lists heads. The umtx sleep queues for PP and PI mutexes are split between non-robust and robust. Somewhat unrelated changes in the patch: 1. Style. 2. The fix for proper tdfind() call use in umtxq_sleep_pi() for shared pi mutexes. 3. Removal of the userspace struct pthread_mutex m_owner field. 4. The sysctl kern.ipc.umtx_vnode_persistent is added, which controls the lifetime of the shared mutex associated with a vnode' page. Reviewed by: jilles (previous version, supposedly the objection was fixed) Discussed with: brooks, Martin Simmons <martin@lispworks.com> (some aspects) Tested by: pho Sponsored by: The FreeBSD Foundation
220 lines
5.5 KiB
Groff
220 lines
5.5 KiB
Groff
.\" Copyright (C) 2000 Jason Evans <jasone@FreeBSD.org>.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice(s), this list of conditions and the following disclaimer as
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.\" the first lines of this file unmodified other than the possible
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.\" addition of one or more copyright notices.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice(s), this list of conditions and the following disclaimer in
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.\" the documentation and/or other materials provided with the
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.\" distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
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.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.Dd April 29, 2016
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.Dt PTHREAD_MUTEXATTR 3
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.Os
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.Sh NAME
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.Nm pthread_mutexattr_init ,
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.Nm pthread_mutexattr_destroy ,
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.Nm pthread_mutexattr_setprioceiling ,
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.Nm pthread_mutexattr_getprioceiling ,
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.Nm pthread_mutexattr_setprotocol ,
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.Nm pthread_mutexattr_getprotocol ,
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.Nm pthread_mutexattr_setrobust ,
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.Nm pthread_mutexattr_getrobust ,
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.Nm pthread_mutexattr_settype ,
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.Nm pthread_mutexattr_gettype
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.Nd mutex attribute operations
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.Sh LIBRARY
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.Lb libpthread
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.Sh SYNOPSIS
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.In pthread.h
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.Ft int
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.Fn pthread_mutexattr_init "pthread_mutexattr_t *attr"
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.Ft int
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.Fn pthread_mutexattr_destroy "pthread_mutexattr_t *attr"
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.Ft int
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.Fn pthread_mutexattr_setprioceiling "pthread_mutexattr_t *attr" "int prioceiling"
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.Ft int
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.Fn pthread_mutexattr_getprioceiling "pthread_mutexattr_t *attr" "int *prioceiling"
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.Ft int
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.Fn pthread_mutexattr_setprotocol "pthread_mutexattr_t *attr" "int protocol"
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.Ft int
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.Fn pthread_mutexattr_getprotocol "pthread_mutexattr_t *attr" "int *protocol"
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.Ft int
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.Fn pthread_mutexattr_setrobust "pthread_mutexattr_t *attr" "int robust"
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.Ft int
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.Fn pthread_mutexattr_getrobust "pthread_mutexattr_t *attr" "int *robust"
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.Ft int
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.Fn pthread_mutexattr_settype "pthread_mutexattr_t *attr" "int type"
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.Ft int
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.Fn pthread_mutexattr_gettype "pthread_mutexattr_t *attr" "int *type"
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.Sh DESCRIPTION
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Mutex attributes are used to specify parameters to
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.Fn pthread_mutex_init .
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One attribute object can be used in multiple calls to
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.Fn pthread_mutex_init ,
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with or without modifications between calls.
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.Pp
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The
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.Fn pthread_mutexattr_init
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function initializes
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.Fa attr
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with all the default mutex attributes.
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.Pp
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The
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.Fn pthread_mutexattr_destroy
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function destroys
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.Fa attr .
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.Pp
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The
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.Fn pthread_mutexattr_set*
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functions set the attribute that corresponds to each function name.
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.Pp
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The
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.Fn pthread_mutexattr_get*
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functions copy the value of the attribute that corresponds to each function name
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to the location pointed to by the second function parameter.
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.Sh RETURN VALUES
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If successful, these functions return 0.
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Otherwise, an error number is returned to indicate the error.
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.Sh ERRORS
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The
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.Fn pthread_mutexattr_init
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er ENOMEM
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Out of memory.
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.El
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.Pp
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The
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.Fn pthread_mutexattr_destroy
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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Invalid value for
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.Fa attr .
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.El
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.Pp
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The
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.Fn pthread_mutexattr_setprioceiling
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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Invalid value for
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.Fa attr ,
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or invalid value for
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.Fa prioceiling .
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.El
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.Pp
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The
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.Fn pthread_mutexattr_getprioceiling
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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Invalid value for
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.Fa attr .
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.El
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.Pp
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The
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.Fn pthread_mutexattr_setprotocol
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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Invalid value for
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.Fa attr ,
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or invalid value for
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.Fa protocol .
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.El
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.Pp
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The
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.Fn pthread_mutexattr_getprotocol
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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Invalid value for
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.Fa attr .
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.El
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.Pp
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The
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.Fn pthread_mutexattr_settype
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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Invalid value for
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.Fa attr ,
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or invalid value for
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.Fa type .
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.El
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.Pp
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The
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.Fn pthread_mutexattr_gettype
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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Invalid value for
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.Fa attr .
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.El
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.Pp
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The
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.Fn pthread_mutexattr_setrobust
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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Invalid value for
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.Fa attr ,
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or invalid value for
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.Fa robust .
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.El
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.Pp
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The
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.Fn pthread_mutexattr_getrobust
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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Invalid value for
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.Fa attr .
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.El
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.Sh SEE ALSO
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.Xr pthread_mutex_init 3
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.Sh STANDARDS
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The
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.Fn pthread_mutexattr_init
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and
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.Fn pthread_mutexattr_destroy
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functions conform to
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.St -p1003.1-96
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.Pp
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The
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.Fn pthread_mutexattr_setprioceiling ,
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.Fn pthread_mutexattr_getprioceiling ,
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.Fn pthread_mutexattr_setprotocol ,
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.Fn pthread_mutexattr_getprotocol ,
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.Fn pthread_mutexattr_settype ,
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and
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.Fn pthread_mutexattr_gettype
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functions conform to
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.St -susv2 .
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The
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.Fn pthread_mutexattr_setrobust
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and
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.Fn pthread_mutexattr_getrobust
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functions conform to
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.St -susv4 .
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