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
       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).

       ┌──────────────────┬───────────────┬─────────┐
       │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 */

EXAMPLES
       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 5.09 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                                2020-06-09                      GET_NPROCS(3)