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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | STANDARDS | NOTES | EXAMPLES | SEE ALSO | COLOPHON |
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get_nprocs(3) Library Functions Manual get_nprocs(3)
get_nprocs, get_nprocs_conf - get number of processors
Standard C library (libc, -lc)
#include <sys/sysinfo.h>
int get_nprocs(void);
int get_nprocs_conf(void);
The function get_nprocs_conf() returns the number of processors
configured by the operating system.
The function get_nprocs() returns the number of processors
currently available in the system. This may be less than the
number returned by get_nprocs_conf() because processors may be
offline (e.g., on hotpluggable systems).
As given in DESCRIPTION.
For an explanation of the terms used in this section, see
attributes(7).
โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโฌโโโโโโโโโโโโโโโโฌโโโโโโโโโโ
โ Interface โ Attribute โ Value โ
โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโผโโโโโโโโโโโโโโโโผโโโโโโโโโโค
โ get_nprocs(), get_nprocs_conf() โ Thread safety โ MT-Safe โ
โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโดโโโโโโโโโโโโโโโโดโโโโโโโโโโ
GNU.
The current implementation of these functions is rather expensive,
since they open and parse files in the /sys filesystem each time
they are called.
The following sysconf(3) calls make use of the functions
documented on this page to return the same information.
np = sysconf(_SC_NPROCESSORS_CONF); /* processors configured */
np = sysconf(_SC_NPROCESSORS_ONLN); /* processors available */
The following example shows how get_nprocs() and get_nprocs_conf()
can be used.
#include <stdio.h>
#include <stdlib.h>
#include <sys/sysinfo.h>
int
main(void)
{
printf("This system has %d processors configured and "
"%d processors available.\n",
get_nprocs_conf(), get_nprocs());
exit(EXIT_SUCCESS);
}
nproc(1)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
โจhttps://www.kernel.org/doc/man-pages/โฉ. If you have a bug report
for this manual page, see
โจhttps://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTINGโฉ.
This page was obtained from the tarball man-pages-6.18.tar.gz
fetched from
โจhttps://mirrors.edge.kernel.org/pub/linux/docs/man-pages/โฉ on
2026-05-24. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.18 2026-02-08 get_nprocs(3)
Pages that refer to this page: sched_setaffinity(2), sysconf(3)
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HTML rendering created 2026-05-30 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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