febae919ac
Note: clock accepts CLOCK_VIRTUAL and CLOCK_PROF too, but this seems broken as it simply waits for the difference of the current and given value of the clock as if it were CLOCK_MONOTONIC. So document only CLOCK_REALTIME and CLOCK_MONOTONIC as allowed. MFC after: 1 week
175 lines
4.9 KiB
Groff
175 lines
4.9 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 May 9, 2010
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.Dt PTHREAD_CONDATTR 3
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.Os
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.Sh NAME
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.Nm pthread_condattr_init ,
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.Nm pthread_condattr_destroy ,
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.Nm pthread_condattr_getclock ,
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.Nm pthread_condattr_setclock ,
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.Nm pthread_condattr_getpshared ,
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.Nm pthread_condattr_setpshared ,
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.Nd condition 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_condattr_init "pthread_condattr_t *attr"
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.Ft int
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.Fn pthread_condattr_destroy "pthread_condattr_t *attr"
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.Ft int
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.Fn pthread_condattr_getclock "pthread_condattr_t * restrict attr" "clock_t * restrict clock_id"
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.Ft int
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.Fn pthread_condattr_setclock "pthread_condattr_t *attr" "clock_t clock_id"
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.Ft int
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.Fn pthread_condattr_getpshared "pthread_condattr_t * restrict attr" "int * restrict pshared"
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.Ft int
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.Fn pthread_condattr_setpshared "pthread_condattr_t *attr" "int pshared"
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.Sh DESCRIPTION
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Condition attribute objects are used to specify parameters to
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.Fn pthread_cond_init .
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.Pp
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The
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.Fn pthread_condattr_init
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function initializes a condition attribute object with the default attributes.
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.Pp
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The
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.Fn pthread_condattr_destroy
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function destroys a condition attribute object.
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.Pp
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The
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.Fn pthread_condattr_getclock
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function will put the value of the clock attribute from
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.Fa attr
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into the memory area pointed to by
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.Fa clock_id .
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The
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.Fn pthread_condattr_setclock
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function will set the clock attribute of
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.Fa attr
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to the value specified in
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.Fa clock_id .
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The clock attribute affects the interpretation of
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.Fa abstime
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in
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.Xr pthread_cond_timedwait 3
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and may be set to
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.Dv CLOCK_REALTIME
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(default)
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or
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.Dv CLOCK_MONOTONIC .
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.Pp
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The
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.Fn pthread_condattr_getpshared
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function will put the value of the process-shared attribute from
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.Fa attr
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into the memory area pointed to by
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.Fa pshared .
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The
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.Fn pthread_condattr_setpshared
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function will set the process-shared attribute of
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.Fa attr
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to the value specified in
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.Fa pshared .
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The argument
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.Fa pshared
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may have one of the following values:
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.Bl -tag -width ".Dv PTHREAD_PROCESS_PRIVATE"
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.It Dv PTHREAD_PROCESS_PRIVATE
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The condition variable it is attached to may only be accessed by
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threads in the same process as the one that created the object.
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.It Dv PTHREAD_PROCESS_SHARED
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The condition variable it is attached to may be accessed by
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threads in processes other than the one that created the object.
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.El
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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_condattr_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_condattr_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_condattr_setclock
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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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The value specified in
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.Fa clock_id
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is not one of the allowed values.
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.El
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.Pp
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The
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.Fn pthread_condattr_setpshared
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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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The value specified in
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.Fa pshared
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is not one of the allowed values.
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.El
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.Sh SEE ALSO
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.Xr pthread_cond_init 3 ,
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.Xr pthread_cond_timedwait 3
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.Sh STANDARDS
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The
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.Fn pthread_condattr_init
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and
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.Fn pthread_condattr_destroy
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functions conform to
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.St -p1003.1-96
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.Sh BUGS
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The implementation of
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condition variables
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does not fully conform to
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.St -p1003.2
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because the process-shared attribute is ignored;
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if any value other than
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.Dv PTHREAD_PROCESSES_PRIVATE
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is specified in a call to
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.Fn pthread_condattr_setpshared ,
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it will return
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.Er EINVAL .
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