get_nprocs, get_nprocs_conf - get number of processors
#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).
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
| get_nprocs (), get_nprocs_conf () | Thread safety | MT-Safe |
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 <stdlib.h>
#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()); exit(EXIT_SUCCESS);
}