165 lines
3.7 KiB
HTML
165 lines
3.7 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 GETDTABLESIZE</TITLE>
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</HEAD><BODY>
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<H1>GETDTABLESIZE</H1>
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Section: Linux Programmer's Manual (3)<BR>Updated: 2016-03-15<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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getdtablesize - get file descriptor table size
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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/unistd.h">unistd.h</A>></B>
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<P>
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<B>int getdtablesize(void);</B>
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<P>
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Feature Test Macro Requirements for glibc (see
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<B><A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</A></B>(7)):
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<P>
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<B>getdtablesize</B>():
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<DL COMPACT><DT id="1"><DD>
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<DL COMPACT>
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<DT id="2">Since glibc 2.12:<DD>
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<PRE>
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/* Glibc since 2.19: */ _DEFAULT_SOURCE
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|| /* Glibc versions <= 2.19: */ _BSD_SOURCE
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|| ! (_POSIX_C_SOURCE >= 200112L)
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<DT id="3"></PRE>
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<DD>
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Before glibc 2.12:
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_BSD_SOURCE || _XOPEN_SOURCE >= 500
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</DL>
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</DL>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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<B>getdtablesize</B>()
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returns the maximum number of files a process can have open,
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one more than the largest possible value for a file descriptor.
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<A NAME="lbAE"> </A>
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<H2>RETURN VALUE</H2>
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The current limit on the number of open files per process.
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<A NAME="lbAF"> </A>
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<H2>ERRORS</H2>
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On Linux,
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<B>getdtablesize</B>()
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can return any of the errors described for
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<B><A HREF="/cgi-bin/man/man2html?2+getrlimit">getrlimit</A></B>(2);
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see NOTES below.
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<A NAME="lbAG"> </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>getdtablesize</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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<A NAME="lbAH"> </A>
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<H2>CONFORMING TO</H2>
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SVr4, 4.4BSD (the
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<B>getdtablesize</B>()
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function first appeared in 4.2BSD).
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It is not specified in POSIX.1;
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portable applications should employ
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<I>sysconf(_SC_OPEN_MAX)</I>
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instead of this call.
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<A NAME="lbAI"> </A>
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<H2>NOTES</H2>
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<B>getdtablesize</B>()
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is implemented as a libc library function.
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The glibc version calls
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<B><A HREF="/cgi-bin/man/man2html?2+getrlimit">getrlimit</A></B>(2)
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and returns the current
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<B>RLIMIT_NOFILE</B>
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limit, or
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<B>OPEN_MAX</B>
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when that fails.
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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?2+close">close</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+dup">dup</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+getrlimit">getrlimit</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+open">open</A></B>(2)
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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="4"><A HREF="#lbAB">NAME</A><DD>
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<DT id="5"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="6"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="7"><A HREF="#lbAE">RETURN VALUE</A><DD>
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<DT id="8"><A HREF="#lbAF">ERRORS</A><DD>
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<DT id="9"><A HREF="#lbAG">ATTRIBUTES</A><DD>
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<DT id="10"><A HREF="#lbAH">CONFORMING TO</A><DD>
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<DT id="11"><A HREF="#lbAI">NOTES</A><DD>
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<DT id="12"><A HREF="#lbAJ">SEE ALSO</A><DD>
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<DT id="13"><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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