get_nprocs, get_nprocs_conf - get number of processors
Contents
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 │
└─────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘
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).
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);
}
Library
Standard C library (libc, -lc)
Name
get_nprocs, get_nprocs_conf - get number of processors
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 */
Return Value
As given in DESCRIPTION.
See Also
nproc(1) Linux man-pages 6.9.1 2024-06-15 get_nprocs(3)
Standards
GNU.
Synopsis
#include<sys/sysinfo.h>intget_nprocs(void);intget_nprocs_conf(void);
