man-pages/man3/get_phys_pages.3.html
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<H1>GET_PHYS_PAGES</H1>
Section: Linux Programmer's Manual (3)<BR>Updated: 2019-03-06<BR><A HREF="#index">Index</A>
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>
get_phys_pages, get_avphys_pages - get total and available physical
page counts
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<PRE>
<B>#include &lt;<A HREF="file:///usr/include/sys/sysinfo.h">sys/sysinfo.h</A>&gt;</B>
<B>long int get_phys_pages(void);</B>
<B>long int get_avphys_pages(void);</B>
</PRE>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
The function
<B>get_phys_pages</B>()
returns the total number of physical pages of memory available on the system.
<P>
The function
<B>get_avphys_pages</B>()
returns the number of currently available physical pages of memory on the
system.
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
On success,
these functions return a nonnegative value as given in DESCRIPTION.
On failure, they return -1 and set
<I>errno</I>
to indicate the cause of the error.
<A NAME="lbAF">&nbsp;</A>
<H2>ERRORS</H2>
<DL COMPACT>
<DT id="1"><B>ENOSYS</B>
<DD>
The system could not provide the required information
(possibly because the
<I>/proc</I>
filesystem was not mounted).
</DL>
<A NAME="lbAG">&nbsp;</A>
<H2>CONFORMING TO</H2>
These functions are GNU extensions.
<A NAME="lbAH">&nbsp;</A>
<H2>NOTES</H2>
These functions obtain the required information by scanning the
<I>MemTotal</I>
and
<I>MemFree</I>
fields of
<I>/proc/meminfo</I>.
<P>
The following
<B><A HREF="/cgi-bin/man/man2html?3+sysconf">sysconf</A></B>(3)
calls provide a portable means of obtaining the same information as the
functions described on this page.
<P>
total_pages = sysconf(_SC_PHYS_PAGES); /* total pages */
avl_pages = sysconf(_SC_AVPHYS_PAGES); /* available pages */
<A NAME="lbAI">&nbsp;</A>
<H2>EXAMPLE</H2>
The following example shows how
<B>get_phys_pages</B>()
and
<B>get_avphys_pages</B>()
can be used.
<P>
#include &lt;<A HREF="file:///usr/include/stdio.h">stdio.h</A>&gt;
#include &lt;<A HREF="file:///usr/include/stdlib.h">stdlib.h</A>&gt;
#include &lt;<A HREF="file:///usr/include/sys/sysinfo.h">sys/sysinfo.h</A>&gt;
<P>
int
main(int argc, char *argv[])
{
<BR>&nbsp;&nbsp;&nbsp;&nbsp;printf(&quot;This&nbsp;system&nbsp;has&nbsp;%ld&nbsp;pages&nbsp;of&nbsp;physical&nbsp;memory&nbsp;and&nbsp;&quot;
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&quot;%ld&nbsp;pages&nbsp;of&nbsp;physical&nbsp;memory&nbsp;available.\n&quot;,
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;get_phys_pages(),&nbsp;get_avphys_pages());
<BR>&nbsp;&nbsp;&nbsp;&nbsp;exit(EXIT_SUCCESS);
}
<A NAME="lbAJ">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?3+sysconf">sysconf</A></B>(3)
<A NAME="lbAK">&nbsp;</A>
<H2>COLOPHON</H2>
This page is part of release 5.05 of the Linux
<I>man-pages</I>
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
<P>
<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT id="2"><A HREF="#lbAB">NAME</A><DD>
<DT id="3"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="4"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="5"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DT id="6"><A HREF="#lbAF">ERRORS</A><DD>
<DT id="7"><A HREF="#lbAG">CONFORMING TO</A><DD>
<DT id="8"><A HREF="#lbAH">NOTES</A><DD>
<DT id="9"><A HREF="#lbAI">EXAMPLE</A><DD>
<DT id="10"><A HREF="#lbAJ">SEE ALSO</A><DD>
<DT id="11"><A HREF="#lbAK">COLOPHON</A><DD>
</DL>
<HR>
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Time: 00:05:44 GMT, March 31, 2021
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