get_nprocs_conf(3)

1GET_NPROCS(3)              Linux Programmer's Manual             GET_NPROCS(3)
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NAME

6       get_nprocs, get_nprocs_conf - get number of processors
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SYNOPSIS

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

15       The function get_nprocs_conf() returns the number of processors config‐
16       ured by the operating system.
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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).
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RETURN VALUE

24       As given in DESCRIPTION.
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ATTRIBUTES

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

37       These functions are GNU extensions.
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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.
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44       The following sysconf(3) calls make use of the functions documented  on
45       this page to return the same information.
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47           np = sysconf(_SC_NPROCESSORS_CONF);     /* processors configured */
48           np = sysconf(_SC_NPROCESSORS_ONLN);     /* processors available */
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EXAMPLES

51       The  following example shows how get_nprocs() and get_nprocs_conf() can
52       be used.
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54       #include <stdlib.h>
55       #include <stdio.h>
56       #include <sys/sysinfo.h>
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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       }
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COLOPHON

71       This page is part of release 5.12 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/.
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78GNU                               2021-03-22                     GET_NPROCS(3)