1.\" Copyright (C) 2000 Jason Evans <jasone@FreeBSD.org>. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice(s), this list of conditions and the following disclaimer as 9.\" the first lines of this file unmodified other than the possible 10.\" addition of one or more copyright notices. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice(s), this list of conditions and the following disclaimer in 13.\" the documentation and/or other materials provided with the 14.\" distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 17.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE 20.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 23.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 24.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 25.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 26.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27.\" 28.\" $FreeBSD$ 29.Dd May 9, 2010 30.Dt PTHREAD_CONDATTR 3 31.Os 32.Sh NAME 33.Nm pthread_condattr_init , 34.Nm pthread_condattr_destroy , 35.Nm pthread_condattr_getclock , 36.Nm pthread_condattr_setclock , 37.Nm pthread_condattr_getpshared , 38.Nm pthread_condattr_setpshared 39.Nd condition attribute operations 40.Sh LIBRARY 41.Lb libpthread 42.Sh SYNOPSIS 43.In pthread.h 44.Ft int 45.Fn pthread_condattr_init "pthread_condattr_t *attr" 46.Ft int 47.Fn pthread_condattr_destroy "pthread_condattr_t *attr" 48.Ft int 49.Fn pthread_condattr_getclock "pthread_condattr_t * restrict attr" "clock_t * restrict clock_id" 50.Ft int 51.Fn pthread_condattr_setclock "pthread_condattr_t *attr" "clock_t clock_id" 52.Ft int 53.Fn pthread_condattr_getpshared "pthread_condattr_t * restrict attr" "int * restrict pshared" 54.Ft int 55.Fn pthread_condattr_setpshared "pthread_condattr_t *attr" "int pshared" 56.Sh DESCRIPTION 57Condition attribute objects are used to specify parameters to 58.Fn pthread_cond_init . 59.Pp 60The 61.Fn pthread_condattr_init 62function initializes a condition attribute object with the default attributes. 63.Pp 64The 65.Fn pthread_condattr_destroy 66function destroys a condition attribute object. 67.Pp 68The 69.Fn pthread_condattr_getclock 70function will put the value of the clock attribute from 71.Fa attr 72into the memory area pointed to by 73.Fa clock_id . 74The 75.Fn pthread_condattr_setclock 76function will set the clock attribute of 77.Fa attr 78to the value specified in 79.Fa clock_id . 80The clock attribute affects the interpretation of 81.Fa abstime 82in 83.Xr pthread_cond_timedwait 3 84and may be set to 85.Dv CLOCK_REALTIME 86(default) 87or 88.Dv CLOCK_MONOTONIC . 89.Pp 90The 91.Fn pthread_condattr_getpshared 92function will put the value of the process-shared attribute from 93.Fa attr 94into the memory area pointed to by 95.Fa pshared . 96The 97.Fn pthread_condattr_setpshared 98function will set the process-shared attribute of 99.Fa attr 100to the value specified in 101.Fa pshared . 102The argument 103.Fa pshared 104may have one of the following values: 105.Bl -tag -width ".Dv PTHREAD_PROCESS_PRIVATE" 106.It Dv PTHREAD_PROCESS_PRIVATE 107The condition variable it is attached to may only be accessed by 108threads in the same process as the one that created the object. 109.It Dv PTHREAD_PROCESS_SHARED 110The condition variable it is attached to may be accessed by 111threads in processes other than the one that created the object. 112.El 113.Sh RETURN VALUES 114If successful, these functions return 0. 115Otherwise, an error number is returned to indicate the error. 116.Sh ERRORS 117The 118.Fn pthread_condattr_init 119function will fail if: 120.Bl -tag -width Er 121.It Bq Er ENOMEM 122Out of memory. 123.El 124.Pp 125The 126.Fn pthread_condattr_destroy 127function will fail if: 128.Bl -tag -width Er 129.It Bq Er EINVAL 130Invalid value for 131.Fa attr . 132.El 133.Pp 134The 135.Fn pthread_condattr_setclock 136function will fail if: 137.Bl -tag -width Er 138.It Bq Er EINVAL 139The value specified in 140.Fa clock_id 141is not one of the allowed values. 142.El 143.Pp 144The 145.Fn pthread_condattr_setpshared 146function will fail if: 147.Bl -tag -width Er 148.It Bq Er EINVAL 149The value specified in 150.Fa pshared 151is not one of the allowed values. 152.El 153.Sh SEE ALSO 154.Xr pthread_cond_init 3 , 155.Xr pthread_cond_timedwait 3 156.Sh STANDARDS 157The 158.Fn pthread_condattr_init 159and 160.Fn pthread_condattr_destroy 161functions conform to 162.St -p1003.1-96 163.Sh BUGS 164The implementation of 165condition variables 166does not fully conform to 167.St -p1003.2 168because the process-shared attribute is ignored; 169if any value other than 170.Dv PTHREAD_PROCESSES_PRIVATE 171is specified in a call to 172.Fn pthread_condattr_setpshared , 173it will return 174.Er EINVAL . 175