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| .TH GET_PHYS_PAGES 3 2021-03-22 "GNU" "Linux Programmer's Manual" |
| .SH NAME |
| get_phys_pages, get_avphys_pages \- get total and available physical |
| page counts |
| .SH SYNOPSIS |
| .nf |
| .B "#include <sys/sysinfo.h>" |
| .PP |
| .B long get_phys_pages(void); |
| .B long get_avphys_pages(void); |
| .fi |
| .SH DESCRIPTION |
| The function |
| .BR get_phys_pages () |
| returns the total number of physical pages of memory available on the system. |
| .PP |
| The function |
| .BR get_avphys_pages () |
| returns the number of currently available physical pages of memory on the |
| system. |
| .SH RETURN VALUE |
| On success, |
| these functions return a nonnegative value as given in DESCRIPTION. |
| On failure, they return \-1 and set |
| .I errno |
| to indicate the error. |
| .SH ERRORS |
| .TP |
| .B ENOSYS |
| The system could not provide the required information |
| (possibly because the |
| .I /proc |
| filesystem was not mounted). |
| .SH CONFORMING TO |
| These functions are GNU extensions. |
| .SH NOTES |
| Before glibc 2.23, |
| these functions obtained the required information by scanning the |
| .I MemTotal |
| and |
| .I MemFree |
| fields of |
| .IR /proc/meminfo . |
| Since glibc 2.23, |
| these functions obtain the required information by calling |
| .BR sysinfo (2). |
| .PP |
| The following |
| .BR sysconf (3) |
| calls provide a portable means of obtaining the same information as the |
| functions described on this page. |
| .PP |
| .in +4n |
| .EX |
| total_pages = sysconf(_SC_PHYS_PAGES); /* total pages */ |
| avl_pages = sysconf(_SC_AVPHYS_PAGES); /* available pages */ |
| .EE |
| .in |
| .SH EXAMPLES |
| The following example shows how |
| .BR get_phys_pages () |
| and |
| .BR get_avphys_pages () |
| can be used. |
| .PP |
| .EX |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <sys/sysinfo.h> |
| |
| int |
| main(int argc, char *argv[]) |
| { |
| printf("This system has %ld pages of physical memory and " |
| "%ld pages of physical memory available.\en", |
| get_phys_pages(), get_avphys_pages()); |
| exit(EXIT_SUCCESS); |
| } |
| .EE |
| .SH SEE ALSO |
| .BR sysconf (3) |