1.\" Copyright (c) 2017 The DragonFly Project. All rights reserved. 2.\" 3.\" This code is derived from software contributed to The DragonFly Project 4.\" by Sepherosa Ziehau <sepherosa@gmail.com>. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in 14.\" the documentation and/or other materials provided with the 15.\" distribution. 16.\" 3. Neither the name of The DragonFly Project nor the names of its 17.\" contributors may be used to endorse or promote products derived 18.\" from this software without specific, prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22.\" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23.\" FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 24.\" COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25.\" INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 26.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 30.\" OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31.\" SUCH DAMAGE. 32.\" 33.Dd January 15, 2017 34.Dt PTHREAD_ATTR_SETAFFINITY_NP 2 35.Os 36.Sh NAME 37.Nm pthread_attr_setaffinity_np , 38.Nm pthread_attr_getaffinity_np 39.Nd set and get the thread's CPU affinity mask attribute 40.Sh LIBRARY 41.Lb libpthread 42.Sh SYNOPSIS 43.In pthread.h 44.In pthread_np.h 45.Ft int 46.Fn pthread_attr_setaffinity_np "pthread_attr_t *attr" "size_t cpusetsize" "const cpu_set_t *mask" 47.Ft int 48.Fn pthread_attr_getaffinity_np "const pthread_attr_t *attr" "size_t cpusetsize" "cpu_set_t *mask" 49.Sh DESCRIPTION 50.Pp 51The 52.Fn pthread_attr_setaffinity_np 53sets the CPU affinity mask of the 54.Fa attr 55to the value specified by the 56.Fa mask . 57The 58.Fa cpusetsize 59is the length (in bytes) of the data pointed to by 60.Fa mask . 61Normally this argument would be specified as sizeof(cpu_set_t). 62The threads created by 63.Xr pthread_create 2 64with the 65.Fa attr 66will use the CPU affinity mask of the 67.Fa attr . 68.Pp 69.Fn pthread_attr_getaffinity_np 70writes the CPU affinity mask of the 71.Fa attr 72to the cpu_set_t structure pointed to by 73.Fa mask . 74.Pp 75The cpu_set_t data structure represents a set of CPUs. 76See 77.Xr sched_setaffinity 2 78for details. 79.Sh RETURN VALUES 80If successful, 81these functions will return zero. 82Otherwise an error number will be returned to indicate the error. 83.Sh ERRORS 84The 85.Fn pthread_attr_setaffinity_np 86and 87.Fn pthread_attr_getaffinity_np 88will fail if: 89.Bl -tag -width Er 90.It Bq Er EFAULT 91The 92.Fa mask 93parameter is outside the process's allocated address space. 94.It Bq Er EINVAL 95The 96.Fa attr 97parameter is invalid. 98.It Bq Er EPERM 99The 100.Fa mask 101does not contain a valid CPU. 102.El 103.Sh SEE ALSO 104.Xr pthread_create 3 105.Xr pthread_getaffinity_np 2 106.Xr pthread_setaffinity_np 2 107.Sh HISTORY 108The 109.Fn pthread_attr_setaffinity_np 110and 111.Fn pthread_attr_getaffinity_np 112functions first appeared in 113.Dx 4.7 . 114