get_nprocs_conf(3)

1GET_NPROCS(3)              Linux Programmer's Manual             GET_NPROCS(3)
2
3
4

NAME

6       get_nprocs, get_nprocs_conf - get number of processors
7

SYNOPSIS

9       #include <sys/sysinfo.h>
10
11       int get_nprocs(void);
12       int get_nprocs_conf(void);
13

DESCRIPTION

15       The function get_nprocs_conf() returns the number of processors config‐
16       ured by the operating system.
17
18       The function get_nprocs() returns the number  of  processors  currently
19       available  in the system.  This may be less than the number returned by
20       get_nprocs_conf() because processors may be offline (e.g., on  hotplug‐
21       gable systems).
22

RETURN VALUE

24       As given in DESCRIPTION.
25

ATTRIBUTES

27       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
28       tributes(7).
29
30       ┌────────────────────────────────────────────┬───────────────┬─────────┐
31       │Interface                                   │ Attribute     │ Value   │
32       ├────────────────────────────────────────────┼───────────────┼─────────┤
33       │get_nprocs(), get_nprocs_conf()             │ Thread safety │ MT-Safe │
34       └────────────────────────────────────────────┴───────────────┴─────────┘
35

CONFORMING TO

37       These functions are GNU extensions.
38

NOTES

40       The current implementation of  these  functions  is  rather  expensive,
41       since  they  open and parse files in the /sys filesystem each time they
42       are called.
43
44       The following sysconf(3) calls make use of the functions documented  on
45       this page to return the same information.
46
47           np = sysconf(_SC_NPROCESSORS_CONF);     /* processors configured */
48           np = sysconf(_SC_NPROCESSORS_ONLN);     /* processors available */
49

EXAMPLES

51       The  following example shows how get_nprocs() and get_nprocs_conf() can
52       be used.
53
54       #include <stdlib.h>
55       #include <stdio.h>
56       #include <sys/sysinfo.h>
57
58       int
59       main(int argc, char *argv[])
60       {
61           printf("This system has %d processors configured and "
62                   "%d processors available.\n",
63                   get_nprocs_conf(), get_nprocs());
64           exit(EXIT_SUCCESS);
65       }
66

COLOPHON

71       This page is part of release 5.13 of the Linux  man-pages  project.   A
72       description  of  the project, information about reporting bugs, and the
73       latest    version    of    this    page,    can     be     found     at
74       https://www.kernel.org/doc/man-pages/.
75
76
77
78GNU                               2021-03-22                     GET_NPROCS(3)