get_nprocs(3) Library Functions Manual get_nprocs(3)
NAME
get_nprocs, get_nprocs_conf - get number of processors
LIBRARY
Standard C library (libc, -lc)
SYNOPSIS
#include <sys/sysinfo.h>
int get_nprocs(void);
int get_nprocs_conf(void);
DESCRIPTION
The function get_nprocs_conf() returns the number of processors config-
ured 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 hotplug-
gable systems).
RETURN VALUE
As given in DESCRIPTION.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
┌────────────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├────────────────────────────────────────────┼───────────────┼─────────┤
│get_nprocs(), get_nprocs_conf() │ Thread safety │ MT-Safe │
└────────────────────────────────────────────┴───────────────┴─────────┘
STANDARDS
These functions are GNU extensions.
NOTES
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 */
EXAMPLES
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);
}
SEE ALSO
nproc(1)
Linux man-pages 6.03 2022-12-15 get_nprocs(3)
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