man-pages/man3/getusershell.3.html
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<H1>GETUSERSHELL</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>
getusershell, setusershell, endusershell - get permitted user shells
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<PRE>
<B>#include &lt;<A HREF="file:///usr/include/unistd.h">unistd.h</A>&gt;</B>
<B>char *getusershell(void);</B>
<B>void setusershell(void);</B>
<B>void endusershell(void);</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>getusershell</B>(),
<B>setusershell</B>(),
<B>endusershell</B>():
<PRE>
Since glibc 2.21:
_DEFAULT_SOURCE
In glibc 2.19 and 2.20:
_DEFAULT_SOURCE || (_XOPEN_SOURCE &amp;&amp; _XOPEN_SOURCE&nbsp;&lt;&nbsp;500)
Up to and including glibc 2.19:
_BSD_SOURCE || (_XOPEN_SOURCE &amp;&amp; _XOPEN_SOURCE&nbsp;&lt;&nbsp;500)
</PRE>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
The
<B>getusershell</B>()
function returns the next line from the file
<I>/etc/shells</I>,
opening the file if necessary.
The line should contain
the pathname of a valid user shell.
If
<I>/etc/shells</I>
does not exist or
is unreadable,
<B>getusershell</B>()
behaves as if
<I>/bin/sh</I>
and
<I>/bin/csh</I>
were listed in the file.
<P>
The
<B>setusershell</B>()
function rewinds
<I>/etc/shells</I>.
<P>
The
<B>endusershell</B>()
function closes
<I>/etc/shells</I>.
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
The
<B>getusershell</B>()
function returns NULL on end-of-file.
<A NAME="lbAF">&nbsp;</A>
<H2>FILES</H2>
<PRE>
/etc/shells
</PRE>
<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>getusershell</B>(),
<B>setusershell</B>(),
<BR>
<B>endusershell</B>()
</TD><TD>Thread safety</TD><TD>MT-Unsafe<BR></TD></TR>
</TABLE>
<A NAME="lbAH">&nbsp;</A>
<H2>CONFORMING TO</H2>
4.3BSD.
<A NAME="lbAI">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?5+shells">shells</A></B>(5)
<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="1"><A HREF="#lbAB">NAME</A><DD>
<DT id="2"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="3"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="4"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DT id="5"><A HREF="#lbAF">FILES</A><DD>
<DT id="6"><A HREF="#lbAG">ATTRIBUTES</A><DD>
<DT id="7"><A HREF="#lbAH">CONFORMING TO</A><DD>
<DT id="8"><A HREF="#lbAI">SEE ALSO</A><DD>
<DT id="9"><A HREF="#lbAJ">COLOPHON</A><DD>
</DL>
<HR>
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