Manpages - get_nprocs_conf.3

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).

As given in DESCRIPTION.

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

These functions are GNU extensions.

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);
  }

*nproc*(1)

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