get_nprocs

GET_NPROCS(3)              Linux Programmer's Manual             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 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
       attributes(7).

       +------------------+---------------+---------+
       |Interface         | Attribute     | Value   |
       +------------------+---------------+---------+
       |get_nprocs(),     | Thread safety | MT-Safe |
       |get_nprocs_conf() |               |         |
       +------------------+---------------+---------+

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 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 */

EXAMPLE
       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);
       }

SEE ALSO
       nproc(1)

COLOPHON
       This page is part of release 4.15 of the Linux  man-pages  project.   A
       description  of  the project, information about reporting bugs, and the
       latest    version    of    this    page,    can     be     found     at
       https://www.kernel.org/doc/man-pages/.

GNU                               2017-09-15                     GET_NPROCS(3)
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