161 lines
3.9 KiB
HTML
161 lines
3.9 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML><HEAD><TITLE>Man page of GET_NPROCS</TITLE>
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</HEAD><BODY>
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<H1>GET_NPROCS</H1>
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Section: Linux Programmer's Manual (3)<BR>Updated: 2019-03-06<BR><A HREF="#index">Index</A>
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<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
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<A NAME="lbAB"> </A>
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<H2>NAME</H2>
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get_nprocs, get_nprocs_conf - get number of processors
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<B>#include <<A HREF="file:///usr/include/sys/sysinfo.h">sys/sysinfo.h</A>></B>
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<P>
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<B>int get_nprocs(void);</B>
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<BR>
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<B>int get_nprocs_conf(void);</B>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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The function
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<B>get_nprocs_conf</B>()
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returns the number of processors configured by the operating system.
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<P>
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The function
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<B>get_nprocs</B>()
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returns the number of processors currently available in the system.
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This may be less than the number returned by
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<B>get_nprocs_conf</B>()
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because processors may be offline (e.g., on hotpluggable systems).
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<A NAME="lbAE"> </A>
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<H2>RETURN VALUE</H2>
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As given in DESCRIPTION.
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<A NAME="lbAF"> </A>
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<H2>ATTRIBUTES</H2>
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For an explanation of the terms used in this section, see
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<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
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<TABLE BORDER>
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<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
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<TR VALIGN=top><TD>
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<B>get_nprocs</B>(),
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<BR>
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<B>get_nprocs_conf</B>()
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</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
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</TABLE>
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<P>
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<A NAME="lbAG"> </A>
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<H2>CONFORMING TO</H2>
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These functions are GNU extensions.
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<A NAME="lbAH"> </A>
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<H2>NOTES</H2>
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The current
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implementation of these functions is rather expensive,
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since they open and parse files in the
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<I>/sys</I>
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filesystem each time they are called.
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<P>
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The following
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<B><A HREF="/cgi-bin/man/man2html?3+sysconf">sysconf</A></B>(3)
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calls make use of the functions documented on this page
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to return the same information.
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<P>
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np = sysconf(_SC_NPROCESSORS_CONF); /* processors configured */
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np = sysconf(_SC_NPROCESSORS_ONLN); /* processors available */
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<A NAME="lbAI"> </A>
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<H2>EXAMPLE</H2>
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The following example shows how
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<B>get_nprocs</B>()
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and
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<B>get_nprocs_conf</B>()
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can be used.
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<P>
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#include <<A HREF="file:///usr/include/stdlib.h">stdlib.h</A>>
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#include <<A HREF="file:///usr/include/stdio.h">stdio.h</A>>
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#include <<A HREF="file:///usr/include/sys/sysinfo.h">sys/sysinfo.h</A>>
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<P>
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int
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main(int argc, char *argv[])
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{
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<BR> printf("This system has %d processors configured and "
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<BR> "%d processors available.\n",
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<BR> get_nprocs_conf(), get_nprocs());
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<BR> exit(EXIT_SUCCESS);
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}
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<A NAME="lbAJ"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?1+nproc">nproc</A></B>(1)
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<A NAME="lbAK"> </A>
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<H2>COLOPHON</H2>
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This page is part of release 5.05 of the Linux
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<I>man-pages</I>
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project.
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A description of the project,
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information about reporting bugs,
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and the latest version of this page,
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can be found at
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<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
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<P>
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<HR>
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<A NAME="index"> </A><H2>Index</H2>
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<DL>
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<DT id="1"><A HREF="#lbAB">NAME</A><DD>
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<DT id="2"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="3"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="4"><A HREF="#lbAE">RETURN VALUE</A><DD>
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<DT id="5"><A HREF="#lbAF">ATTRIBUTES</A><DD>
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<DT id="6"><A HREF="#lbAG">CONFORMING TO</A><DD>
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<DT id="7"><A HREF="#lbAH">NOTES</A><DD>
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<DT id="8"><A HREF="#lbAI">EXAMPLE</A><DD>
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<DT id="9"><A HREF="#lbAJ">SEE ALSO</A><DD>
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<DT id="10"><A HREF="#lbAK">COLOPHON</A><DD>
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</DL>
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<HR>
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This document was created by
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<A HREF="/cgi-bin/man/man2html">man2html</A>,
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using the manual pages.<BR>
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Time: 00:05:44 GMT, March 31, 2021
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</BODY>
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</HTML>
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