GET_NPROCS(3)

NAME
get_nprocs, get_nprocs_conf - get number of processors

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 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).

RETURN VALUE
As given in DESCRIPTION.

CONFORMING TO
These functions are GNU extensions.

NOTES
The current implementation of these functions is rather expensive, since they open and parse files in the /sys file system 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 */

EXAMPLE
The following example shows how get_nprocs() and get_nprocs_conf() can be used.
#include <stdio.h>
#include <sys/sysinfo.h>
int
main(int argc, char *argv[])
{
    printf("This system has %d processors configured and "
            "%d processors available.\n",
            get_nprocs_conf(), get_nprocs());
    return 0;
}

COLOPHON
This page is part of release 3.39 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.