man-pages/man3/opendir.3.html
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<H1>OPENDIR</H1>
Section: Linux Programmer's Manual (3)<BR>Updated: 2017-09-15<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>
opendir, fdopendir - open a directory
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<PRE>
<B>#include &lt;<A HREF="file:///usr/include/sys/types.h">sys/types.h</A>&gt;</B>
<B>#include &lt;<A HREF="file:///usr/include/dirent.h">dirent.h</A>&gt;</B>
<B>DIR *opendir(const char *</B><I>name</I><B>);</B>
<B>DIR *fdopendir(int </B><I>fd</I><B>);</B>
</PRE>
<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>fdopendir</B>():
<DL COMPACT><DT id="1"><DD>
<DL COMPACT>
<DT id="2">Since glibc 2.10:<DD>
_POSIX_C_SOURCE&nbsp;&gt;=&nbsp;200809L
<DT id="3">Before glibc 2.10:<DD>
_GNU_SOURCE
</DL>
</DL>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
The
<B>opendir</B>()
function opens a directory stream corresponding to the
directory <I>name</I>, and returns a pointer to the directory stream.
The stream is positioned at the first entry in the directory.
<P>
The
<B>fdopendir</B>()
function
is like
<B>opendir</B>(),
but returns a directory stream for the directory referred
to by the open file descriptor
<I>fd</I>.
After a successful call to
<B>fdopendir</B>(),
<I>fd</I>
is used internally by the implementation,
and should not otherwise be used by the application.
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
The
<B>opendir</B>()
and
<B>fdopendir</B>()
functions return a pointer to the directory stream.
On error, NULL is returned, and
<I>errno</I>
is set appropriately.
<A NAME="lbAF">&nbsp;</A>
<H2>ERRORS</H2>
<DL COMPACT>
<DT id="4"><B>EACCES</B>
<DD>
Permission denied.
<DT id="5"><B>EBADF</B>
<DD>
<I>fd</I>
is not a valid file descriptor opened for reading.
<DT id="6"><B>EMFILE</B>
<DD>
The per-process limit on the number of open file descriptors has been reached.
<DT id="7"><B>ENFILE</B>
<DD>
The system-wide limit on the total number of open files has been reached.
<DT id="8"><B>ENOENT</B>
<DD>
Directory does not exist, or <I>name</I> is an empty string.
<DT id="9"><B>ENOMEM</B>
<DD>
Insufficient memory to complete the operation.
<DT id="10"><B>ENOTDIR</B>
<DD>
<I>name</I> is not a directory.
</DL>
<A NAME="lbAG">&nbsp;</A>
<H2>VERSIONS</H2>
<B>fdopendir</B>()
is available in glibc since version 2.4.
<A NAME="lbAH">&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>opendir</B>(),
<B>fdopendir</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
</TABLE>
<A NAME="lbAI">&nbsp;</A>
<H2>CONFORMING TO</H2>
<B>opendir</B>()
is present on SVr4, 4.3BSD, and specified in POSIX.1-2001.
<B>fdopendir</B>()
is specified in POSIX.1-2008.
<A NAME="lbAJ">&nbsp;</A>
<H2>NOTES</H2>
Filename entries can be read from a directory stream using
<B><A HREF="/cgi-bin/man/man2html?3+readdir">readdir</A></B>(3).
<P>
The underlying file descriptor of the directory stream can be obtained using
<B><A HREF="/cgi-bin/man/man2html?3+dirfd">dirfd</A></B>(3).
<P>
The
<B>opendir</B>()
function sets the close-on-exec flag for the file descriptor underlying the
<I>DIR *</I>.
The
<B>fdopendir</B>()
function leaves the setting of the close-on-exec
flag unchanged for the file descriptor,
<I>fd</I>.
POSIX.1-200x leaves it unspecified whether a successful call to
<B>fdopendir</B>()
will set the close-on-exec flag for the file descriptor,
<I>fd</I>.
<A NAME="lbAK">&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+dirfd">dirfd</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="lbAL">&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="11"><A HREF="#lbAB">NAME</A><DD>
<DT id="12"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="13"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="14"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DT id="15"><A HREF="#lbAF">ERRORS</A><DD>
<DT id="16"><A HREF="#lbAG">VERSIONS</A><DD>
<DT id="17"><A HREF="#lbAH">ATTRIBUTES</A><DD>
<DT id="18"><A HREF="#lbAI">CONFORMING TO</A><DD>
<DT id="19"><A HREF="#lbAJ">NOTES</A><DD>
<DT id="20"><A HREF="#lbAK">SEE ALSO</A><DD>
<DT id="21"><A HREF="#lbAL">COLOPHON</A><DD>
</DL>
<HR>
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Time: 00:05:49 GMT, March 31, 2021
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