get_phys_pages(3) Library Functions Manual get_phys_pages(3)

get_phys_pages, get_avphys_pages - get total and available physical page counts

Standard C library (libc, -lc)

#include <sys/sysinfo.h>
long get_phys_pages(void);
long get_avphys_pages(void);

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.

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

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


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).

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 */

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>

printf("This system has %ld pages of physical memory and "
"%ld pages of physical memory available.\n",
get_phys_pages(), get_avphys_pages());


2023-10-31 Linux man-pages 6.06