Copyright (c) 2002 The NetBSD Foundation, Inc.
All rights reserved.
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.
3. Neither the name of The NetBSD Foundation nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
Copyright (C) 2000 Jason Evans <jasone@FreeBSD.org>.
All rights reserved.
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(s), this list of conditions and the following disclaimer as
the first lines of this file unmodified other than the possible
addition of one or more copyright notices.
2. Redistributions in binary form must reproduce the above copyright
notice(s), 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 COPYRIGHT HOLDER(S) ``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 COPYRIGHT HOLDER(S) 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.
$FreeBSD: src/lib/libpthread/man/pthread_mutexattr.3,v 1.8 2002/09/16 19:29:29 mini Exp $
.Dd January 30, 2003 .Dt PTHREAD_MUTEXATTR 3 .Os .Sh NAME .Nm pthread_mutexattr_init , .Nm pthread_mutexattr_destroy , .Nm pthread_mutexattr_setprioceiling ,
.Nm pthread_mutexattr_getprioceiling ,
.Nm pthread_mutexattr_setprotocol ,
.Nm pthread_mutexattr_getprotocol ,
.Nm pthread_mutexattr_settype , .Nm pthread_mutexattr_gettype .Nd mutex attribute operations .Sh LIBRARY .Lb libpthread .Sh SYNOPSIS n pthread.h .Ft int .Fn pthread_mutexattr_init "pthread_mutexattr_t *attr" .Ft int .Fn pthread_mutexattr_destroy "pthread_mutexattr_t *attr" .Ft int
.Fn pthread_mutexattr_setprioceiling "pthread_mutexattr_t *attr" "int prioceiling"
.Ft int
.Fn pthread_mutexattr_getprioceiling "pthread_mutexattr_t *attr" "int *prioceiling"
.Ft int
.Fn pthread_mutexattr_setprotocol "pthread_mutexattr_t *attr" "int protocol"
.Ft int
.Fn pthread_mutexattr_getprotocol "pthread_mutexattr_t *attr" "int *protocol"
.Ft int .Fn pthread_mutexattr_settype "pthread_mutexattr_t *attr" "int type" .Ft int .Fn pthread_mutexattr_gettype "pthread_mutexattr_t * restrict attr" "int * restrict type" .Sh DESCRIPTION Mutex attributes are used to specify parameters to .Fn pthread_mutex_init . One attribute object can be used in multiple calls to .Fn pthread_mutex_init , with or without modifications between calls.
p The .Fn pthread_mutexattr_init function initializes .Fa attr with all the default mutex attributes.
p The .Fn pthread_mutexattr_destroy function destroys .Fa attr .
p The .Fn pthread_mutexattr_settype functions set the mutex type value of the attribute. Valid mutex types are: .Dv PTHREAD_MUTEX_NORMAL , .Dv PTHREAD_MUTEX_ERRORCHECK , .Dv PTHREAD_MUTEX_RECURSIVE , and .Dv PTHREAD_MUTEX_DEFAULT . The default mutex type for .Fn pthread_mutexaddr_init is .Dv PTHREAD_MUTEX_DEFAULT .
p .Dv PTHREAD_MUTEX_NORMAL mutexes do not check for usage errors. .Dv PTHREAD_MUTEX_NORMAL mutexes will deadlock if reentered, and result in undefined behavior if a locked mutex is unlocked by another thread. Attempts to unlock an already unlocked .Dv PTHREAD_MUTEX_NORMAL mutex will result in undefined behavior.
p .Dv PTHREAD_MUTEX_ERRORCHECK mutexes do check for usage errors. If an attempt is made to relock a .Dv PTHREAD_MUTEX_ERRORCHECK mutex without first dropping the lock an error will be returned. If a thread attempts to unlock a .Dv PTHREAD_MUTEX_ERRORCHECK mutex that is locked by another thread, an error will be returned. If a thread attempts to unlock a .Dv PTHREAD_MUTEX_ERRORCHECK thread that is unlocked, an error will be returned.
p .Dv PTHREAD_MUTEX_RECURSIVE mutexes allow recursive locking. An attempt to relock a .Dv PTHREAD_MUTEX_RECURSIVE mutex that is already locked by the same thread succeeds. An equivalent number of .Xr pthread_mutex_unlock 3 calls are needed before the mutex will wake another thread waiting on this lock. If a thread attempts to unlock a .Dv PTHREAD_MUTEX_RECURSIVE mutex that is locked by another thread, an error will be returned. If a thread attempts to unlock a .Dv PTHREAD_MUTEX_RECURSIVE thread that is unlocked, an error will be returned.
p .Dv PTHREAD_MUTEX_DEFAULT mutexes result in undefined behavior if reentered. Unlocking a .Dv PTHREAD_MUTEX_DEFAULT mutex locked by another thread will result in undefined behavior. Attempts to unlock an already unlocked .Dv PTHREAD_MUTEX_DEFAULT mutex will result in undefined behavior.
p .Fn pthread_mutexattr_gettype functions copy the type value of the attribute to the location pointed to by the second parameter. .Sh RETURN VALUES If successful, these functions return 0. Otherwise, an error number is returned to indicate the error. .Sh ERRORS .Fn pthread_mutexattr_init shall fail if: l -tag -width Er t Bq Er ENOMEM Insufficient memory exists to initialize the mutex attributes object. .El
p .Fn pthread_mutexattr_settype shall fail if: l -tag -width Er t Bq Er EINVAL The value specified by .Fa type is invalid. .El
p
.Fn pthread_mutexattr_setprioceiling
may fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
Invalid value for
.Fa attr ,
or invalid value for
.Fa prioceiling .
.El
.Pp
.Fn pthread_mutexattr_getprioceiling
may fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
Invalid value for
.Fa attr .
.El
.Pp
.Fn pthread_mutexattr_setprotocol
may fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
Invalid value for
.Fa attr ,
or invalid value for
.Fa protocol .
.El
.Pp
.Fn pthread_mutexattr_getprotocol
may fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
Invalid value for
.Fa attr .
.El
.Pp
p
.Fn pthread_mutexattr_destroy ,
.Fn pthread_mutexattr_settype ,
and
.Fn pthread_mutexattr_gettype
may fail if:
l -tag -width Er t Bq Er EINVAL Invalid value for
.Fa attr .
.El
.Sh SEE ALSO
.Xr pthread_mutex_init 3
.Sh STANDARDS
.Fn pthread_mutexattr_init ,
.Fn pthread_mutexattr_destroy ,
.Fn pthread_mutexattr_settype ,
.Fn pthread_mutexattr_setprioceiling ,
.Fn pthread_mutexattr_getprioceiling ,
.Fn pthread_mutexattr_setprotocol ,
.Fn pthread_mutexattr_getprotocol ,
and
.Fn pthread_mutexattr_gettype
conform to
.St -p1003.1-96 .