get_nprocs(3)                                         Library Functions Manual                                        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);
       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(), get_nprocs_conf()                                                                  │ Thread safety │ MT-Safe │
       └─────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

STANDARDS
       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 <stdio.h>
       #include <stdlib.h>
       #include <sys/sysinfo.h>

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

SEE ALSO
       nproc(1)

Linux man-pages 6.03                                         2022-12-15                                               get_nprocs(3)