man-pages/man3/dirfd.3.html
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<H1>DIRFD</H1>
Section: Linux Programmer's Manual (3)<BR>Updated: 2016-03-15<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>
dirfd - get directory stream file descriptor
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<B>#include &lt;<A HREF="file:///usr/include/sys/types.h">sys/types.h</A>&gt;</B>
<BR>
<B>#include &lt;<A HREF="file:///usr/include/dirent.h">dirent.h</A>&gt;</B>
<P>
<B>int dirfd(DIR *</B><I>dirp</I><B>);</B>
<P>
Feature Test Macro Requirements for glibc (see
<B><A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</A></B>(7)):
<P>
<B>dirfd</B>():
<BR>
<DL COMPACT><DT id="1"><DD>
/* Since glibc 2.10: */ _POSIX_C_SOURCE&nbsp;&gt;=&nbsp;200809L
<BR>&nbsp;&nbsp;&nbsp;&nbsp;||&nbsp;/*&nbsp;Glibc&nbsp;versions&nbsp;&lt;=&nbsp;2.19:&nbsp;*/&nbsp;_BSD_SOURCE&nbsp;||&nbsp;_SVID_SOURCE
</DL>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
The function
<B>dirfd</B>()
returns the file descriptor associated with the directory stream
<I>dirp</I>.
<P>
This file descriptor is the one used internally by the directory stream.
As a result, it is useful only for functions which do not depend on
or alter the file position, such as
<B><A HREF="/cgi-bin/man/man2html?2+fstat">fstat</A></B>(2)
and
<B><A HREF="/cgi-bin/man/man2html?2+fchdir">fchdir</A></B>(2).
It will be automatically closed when
<B><A HREF="/cgi-bin/man/man2html?3+closedir">closedir</A></B>(3)
is called.
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
On success, a nonnegative file descriptor is returned.
On error, -1 is returned, and
<I>errno</I>
is set to indicate the cause of the error.
<A NAME="lbAF">&nbsp;</A>
<H2>ERRORS</H2>
POSIX.1-2008 specifies two errors,
neither of which is returned by the current
implementation.
<DL COMPACT>
<DT id="2"><B>EINVAL</B>
<DD>
<I>dirp</I>
does not refer to a valid directory stream.
<DT id="3"><B>ENOTSUP</B>
<DD>
The implementation does not support the association of a file
descriptor with a directory.
</DL>
<A NAME="lbAG">&nbsp;</A>
<H2>ATTRIBUTES</H2>
For an explanation of the terms used in this section, see
<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
<TABLE BORDER>
<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
<TR VALIGN=top><TD>
<B>dirfd</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
</TABLE>
<A NAME="lbAH">&nbsp;</A>
<H2>CONFORMING TO</H2>
POSIX.1-2008.
This function was a BSD extension, present in 4.3BSD-Reno, not in 4.2BSD.
<A NAME="lbAI">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?2+open">open</A></B>(2),
<B><A HREF="/cgi-bin/man/man2html?3+closedir">closedir</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+opendir">opendir</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+readdir">readdir</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+rewinddir">rewinddir</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+scandir">scandir</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+seekdir">seekdir</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+telldir">telldir</A></B>(3)
<A NAME="lbAJ">&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="4"><A HREF="#lbAB">NAME</A><DD>
<DT id="5"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="6"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="7"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DT id="8"><A HREF="#lbAF">ERRORS</A><DD>
<DT id="9"><A HREF="#lbAG">ATTRIBUTES</A><DD>
<DT id="10"><A HREF="#lbAH">CONFORMING TO</A><DD>
<DT id="11"><A HREF="#lbAI">SEE ALSO</A><DD>
<DT id="12"><A HREF="#lbAJ">COLOPHON</A><DD>
</DL>
<HR>
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Time: 00:05:38 GMT, March 31, 2021
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