1GET_NPROCS(3) Linux Programmer's Manual GET_NPROCS(3)
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6 get_nprocs, get_nprocs_conf - get number of processors
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9 #include <sys/sysinfo.h>
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11 int get_nprocs(void);
12 int get_nprocs_conf(void);
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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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24 As given in DESCRIPTION.
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27 For an explanation of the terms used in this section, see
28 attributes(7).
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30 ┌──────────────────┬───────────────┬─────────┐
31 │Interface │ Attribute │ Value │
32 ├──────────────────┼───────────────┼─────────┤
33 │get_nprocs(), │ Thread safety │ MT-Safe │
34 │get_nprocs_conf() │ │ │
35 └──────────────────┴───────────────┴─────────┘
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38 These functions are GNU extensions.
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41 The current implementation of these functions is rather expensive,
42 since they open and parse files in the /sys filesystem each time they
43 are called.
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45 The following sysconf(3) calls make use of the functions documented on
46 this page to return the same information.
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48 np = sysconf(_SC_NPROCESSORS_CONF); /* processors configured */
49 np = sysconf(_SC_NPROCESSORS_ONLN); /* processors available */
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52 The following example shows how get_nprocs() and get_nprocs_conf() can
53 be used.
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55 #include <stdlib.h>
56 #include <stdio.h>
57 #include <sys/sysinfo.h>
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59 int
60 main(int argc, char *argv[])
61 {
62 printf("This system has %d processors configured and "
63 "%d processors available.\n",
64 get_nprocs_conf(), get_nprocs());
65 exit(EXIT_SUCCESS);
66 }
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69 nproc(1)
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72 This page is part of release 5.04 of the Linux man-pages project. A
73 description of the project, information about reporting bugs, and the
74 latest version of this page, can be found at
75 https://www.kernel.org/doc/man-pages/.
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79GNU 2019-03-06 GET_NPROCS(3)