oracular (3) get_nprocs.3.gz

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

       GNU.

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)