get_phys_pages(3)

get_phys_pages3

Get total and available physical page counts

Usage

#include <sys/sysinfo.h>

long get_phys_pages(void); long get_avphys_pages(void);

Library

Standard C library (libc, -lc)

Overview

The function get_phys_pages() returns the total number of physical pages of memory available on the system.

The function get_avphys_pages() returns the number of currently available physical pages of memory on the system.

Return value

On success, these functions return a nonnegative value as given in DESCRIPTION. On failure, they return -1 and set errno to indicate the error.

Errors

ENOSYS

The system could not provide the required information (possibly because the /proc filesystem was not mounted).

Notes

The following sysconf(3) calls provide a portable means of obtaining the same information as the functions described on this page.

total_pages = sysconf(_SC_PHYS_PAGES);    /* total pages */
avl_pages = sysconf(_SC_AVPHYS_PAGES);    /* available pages */

Examples

The following example shows how get_phys_pages() and get_avphys_pages() can be used.

#include <stdio.h>
#include <stdlib.h>
#include <sys/sysinfo.h>
int
main(void)
{
    printf("This system has %ld pages of physical memory and "
            "%ld pages of physical memory available.\n",
            get_phys_pages(), get_avphys_pages());
    exit(EXIT_SUCCESS);
}

Releases

6 releases since Debian 9 (Stretch); the text changed 5 times.

  1. 9
  2. 10
  3. 11
  4. 12
  5. 13
  6. Arch

Standards

GNU.

History

Before glibc 2.23, these functions obtained the required information by scanning the MemTotal and MemFree fields of /proc/meminfo. Since glibc 2.23, these functions obtain the required information by calling sysinfo(2).

From man-pages 6.19-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.