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);\n
\nint 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.

ATTRIBUTES#

For an explanation of the terms used in this section, see attributes(7).

STANDARDS#

GNU.

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)
{
\n
    printf("This system has %d processors configured and "
\n
            "%d processors available.\n",
\n
            get_nprocs_conf(), get_nprocs());
\n
    exit(EXIT_SUCCESS);
}

SEE ALSO#

nproc(1)