get_phys_pages(3)

1GET_PHYS_PAGES(3)          Linux Programmer's Manual         GET_PHYS_PAGES(3)
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NAME

6       get_phys_pages,  get_avphys_pages  -  get  total and available physical
7       page counts
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SYNOPSIS

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

16       The function get_phys_pages() returns  the  total  number  of  physical
17       pages of memory available on the system.
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19       The  function get_avphys_pages() returns the number of currently avail‐
20       able physical pages of memory on the system.
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RETURN VALUE

23       On success, these functions return a nonnegative value as given in  DE‐
24       SCRIPTION.   On  failure,  they return -1 and set errno to indicate the
25       error.
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ERRORS

28       ENOSYS The system could not provide the required information  (possibly
29              because the /proc filesystem was not mounted).
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CONFORMING TO

32       These functions are GNU extensions.
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NOTES

35       Before glibc 2.23, these functions obtained the required information by
36       scanning the MemTotal and MemFree fields of /proc/meminfo.  Since glibc
37       2.23,  these  functions obtain the required information by calling sys‐
38       info(2).
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40       The following sysconf(3) calls provide a portable  means  of  obtaining
41       the same information as the functions described on this page.
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43           total_pages = sysconf(_SC_PHYS_PAGES);    /* total pages */
44           avl_pages = sysconf(_SC_AVPHYS_PAGES);    /* available pages */
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EXAMPLES

47       The following example shows how get_phys_pages() and get_avphys_pages()
48       can be used.
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50       #include <stdio.h>
51       #include <stdlib.h>
52       #include <sys/sysinfo.h>
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54       int
55       main(int argc, char *argv[])
56       {
57           printf("This system has %ld pages of physical memory and "
58                   "%ld pages of physical memory available.\n",
59                   get_phys_pages(), get_avphys_pages());
60           exit(EXIT_SUCCESS);
61       }
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COLOPHON

67       This page is part of release 5.13 of the Linux  man-pages  project.   A
68       description  of  the project, information about reporting bugs, and the
69       latest    version    of    this    page,    can     be     found     at
70       https://www.kernel.org/doc/man-pages/.
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74GNU                               2021-03-22                 GET_PHYS_PAGES(3)