140 lines
3.5 KiB
Groff
140 lines
3.5 KiB
Groff
.\" Copyright (c) 2004 Michael Telahun Makonnen
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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, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd January 22, 2004
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.Dt PTHREAD_SPIN_INIT 3
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.Os
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.Sh NAME
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.Nm pthread_spin_init , pthread_spin_destroy
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.Nd "initialize or destroy a spin lock"
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.Sh LIBRARY
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.Lb libpthread
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.Lb libthr
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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_spin_init "pthread_spinlock_t *lock" "int pshared"
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.Ft int
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.Fn pthread_spin_destroy "pthread_spinlock_t *lock"
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.Sh DESCRIPTION
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The
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.Fn pthread_spin_init
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function will initialize
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.Fa lock
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to an unlocked state and
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allocate any resources necessary to begin using it.
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If
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.Fa pshared
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is set to
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.Dv PTHREAD_PROCESS_SHARED ,
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any thread,
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whether belonging to the process in which the spinlock was created or not,
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that has access to the memory area where
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.Fa lock
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resides, can use
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.Fa lock .
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If it is set to
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.Dv PTHREAD_PROCESS_PRIVATE ,
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it can only be used by threads within the same process.
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.Pp
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The
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.Fn pthread_spin_destroy
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function will destroy
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.Fa lock
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and release any resources that may have been allocated on its behalf.
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.Sh RETURN VALUES
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If successful,
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both
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.Fn pthread_spin_init
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and
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.Fn pthread_spin_destroy
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will return zero.
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Otherwise, an error number will be returned to indicate the error.
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.Pp
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Neither of these functions will return
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.Er EINTR .
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.Sh ERRORS
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The
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.Fn pthread_spin_init
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and
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.Fn pthread_spin_destroy
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functions will fail if:
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.Bl -tag -width Er
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.It Bq Er EBUSY
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An attempt to initialize or destroy
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.Fa lock
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while it is in use.
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.It Bq Er EINVAL
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The value specified by
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.Fa lock
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is invalid.
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.El
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.Pp
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The
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.Fn pthread_spin_init
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EAGAIN
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Insufficient resources,
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other than memory,
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to initialize
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.Fa lock .
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.It Bq Er ENOMEM
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Insufficient memory to initialize
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.Fa lock .
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.El
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.Sh SEE ALSO
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.Xr pthread_spin_lock 3 ,
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.Xr pthread_spin_unlock 3
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.Sh HISTORY
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The
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.Fn pthread_spin_init
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and
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.Fn pthread_spin_destroy
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functions first appeared in
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.Lb libpthread
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in
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.Fx 5.2 ,
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and in
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.Lb libthr
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in
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.Fx 5.3 .
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.Sh BUGS
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The implementation of
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.Fn pthread_spin_init
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does not fully conform to
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.St -p1003.2
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because the
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.Fa pshared
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argument is ignored in
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.Lb libthr ,
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and in
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.Lb libpthread
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if any value other than
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.Dv PTHREAD_PROCESSES_PRIVATE
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is specified, it returns
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.Er EINVAL .
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