| blob | 334aefd2de155f0aa5af05884a26392fc7657bd5 |
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 The
51 .Fn pthread_attr_setaffinity_np
52 sets the CPU affinity mask of the
53 .Fa attr
54 to the value specified by the
55 .Fa mask .
56 The
57 .Fa cpusetsize
58 is the length (in bytes) of the data pointed to by
59 .Fa mask .
60 Normally this argument would be specified as sizeof(cpu_set_t).
61 The threads created by
62 .Xr pthread_create 3
63 with the
64 .Fa attr
65 will use the CPU affinity mask of the
66 .Fa attr .
67 .Pp
68 .Fn pthread_attr_getaffinity_np
69 writes the CPU affinity mask of the
70 .Fa attr
71 to the cpu_set_t structure pointed to by
72 .Fa mask .
73 .Pp
74 The cpu_set_t data structure represents a set of CPUs.
75 See
76 .Xr sched_setaffinity 2
77 for details.
78 .Sh RETURN VALUES
79 If successful,
80 these functions will return zero.
81 Otherwise an error number will be returned to indicate the error.
82 .Sh ERRORS
83 The
84 .Fn pthread_attr_setaffinity_np
85 and
86 .Fn pthread_attr_getaffinity_np
87 will fail if:
88 .Bl -tag -width Er
89 .It Bq Er EFAULT
90 The
91 .Fa mask
92 parameter is outside the process's allocated address space.
93 .It Bq Er EINVAL
94 The
95 .Fa attr
96 parameter is invalid.
97 .It Bq Er EPERM
98 The
99 .Fa mask
100 does not contain a valid CPU.
101 .El
102 .Sh SEE ALSO
103 .Xr pthread_create 3 ,
104 .Xr pthread_getaffinity_np 3 ,
105 .Xr pthread_setaffinity_np 3
106 .Sh HISTORY
107 The
108 .Fn pthread_attr_setaffinity_np
109 and
110 .Fn pthread_attr_getaffinity_np
111 functions first appeared in
112 .Dx 4.7 .