man-pages/man2/getuid.2.html
2021-03-31 01:06:50 +01:00

160 lines
3.2 KiB
HTML

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<HTML><HEAD><TITLE>Man page of GETUID</TITLE>
</HEAD><BODY>
<H1>GETUID</H1>
Section: Linux Programmer's Manual (2)<BR>Updated: 2019-03-06<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>
getuid, geteuid - get user identity
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<B>#include &lt;<A HREF="file:///usr/include/unistd.h">unistd.h</A>&gt;</B>
<BR>
<B>#include &lt;<A HREF="file:///usr/include/sys/types.h">sys/types.h</A>&gt;</B>
<P>
<B>uid_t getuid(void);</B>
<BR>
<B>uid_t geteuid(void);</B>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
<B>getuid</B>()
returns the real user ID of the calling process.
<P>
<B>geteuid</B>()
returns the effective user ID of the calling process.
<A NAME="lbAE">&nbsp;</A>
<H2>ERRORS</H2>
These functions are always successful.
<A NAME="lbAF">&nbsp;</A>
<H2>CONFORMING TO</H2>
POSIX.1-2001, POSIX.1-2008, 4.3BSD.
<A NAME="lbAG">&nbsp;</A>
<H2>NOTES</H2>
<A NAME="lbAH">&nbsp;</A>
<H3>History</H3>
In UNIX&nbsp;V6 the
<B>getuid</B>()
call returned
<I>(euid &lt;&lt; 8) + uid</I>.
UNIX&nbsp;V7 introduced separate calls
<B>getuid</B>()
and
<B>geteuid</B>().
<P>
The original Linux
<B>getuid</B>()
and
<B>geteuid</B>()
system calls supported only 16-bit user IDs.
Subsequently, Linux 2.4 added
<B>getuid32</B>()
and
<B>geteuid32</B>(),
supporting 32-bit IDs.
The glibc
<B>getuid</B>()
and
<B>geteuid</B>()
wrapper functions transparently deal with the variations across kernel versions.
<P>
On Alpha, instead of a pair of
<B>getuid</B>()
and
<B>geteuid</B>()
system calls, a single
<B>getxuid</B>()
system call is provided, which returns a pair of real and effective UIDs.
The glibc
<B>getuid</B>()
and
<B>geteuid</B>()
wrapper functions transparently deal with this.
See
<B><A HREF="/cgi-bin/man/man2html?2+syscall">syscall</A></B>(2)
for details regarding register mapping.
<A NAME="lbAI">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?2+getresuid">getresuid</A></B>(2),
<B><A HREF="/cgi-bin/man/man2html?2+setreuid">setreuid</A></B>(2),
<B><A HREF="/cgi-bin/man/man2html?2+setuid">setuid</A></B>(2),
<B><A HREF="/cgi-bin/man/man2html?7+credentials">credentials</A></B>(7)
<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">ERRORS</A><DD>
<DT id="5"><A HREF="#lbAF">CONFORMING TO</A><DD>
<DT id="6"><A HREF="#lbAG">NOTES</A><DD>
<DL>
<DT id="7"><A HREF="#lbAH">History</A><DD>
</DL>
<DT id="8"><A HREF="#lbAI">SEE ALSO</A><DD>
<DT id="9"><A HREF="#lbAJ">COLOPHON</A><DD>
</DL>
<HR>
This document was created by
<A HREF="/cgi-bin/man/man2html">man2html</A>,
using the manual pages.<BR>
Time: 00:05:32 GMT, March 31, 2021
</BODY>
</HTML>