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<H1>TCGETPGRP</H1>
Section: Linux Programmer's Manual (3)<BR>Updated: 2015-08-08<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>
tcgetpgrp, tcsetpgrp - get and set terminal foreground process group
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<B>#include &lt;<A HREF="file:///usr/include/unistd.h">unistd.h</A>&gt;</B>
<P>
<B>pid_t tcgetpgrp(int </B><I>fd</I><B>);</B>
<P>
<B>int tcsetpgrp(int </B><I>fd</I><B>, pid_t </B><I>pgrp</I><B>);</B>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
The function
<B>tcgetpgrp</B>()
returns the process group ID of the foreground process group on the
terminal associated to
<I>fd</I>,
which must be the controlling terminal of the calling process.
<P>
The function
<B>tcsetpgrp</B>()
makes the process group with process group ID
<I>pgrp</I>
the foreground process group on the terminal associated to
<I>fd</I>,
which must be the controlling terminal of the calling process,
and still be associated with its session.
Moreover,
<I>pgrp</I>
must be a (nonempty) process group belonging to
the same session as the calling process.
<P>
If
<B>tcsetpgrp</B>()
is called by a member of a background process group in its session,
and the calling process is not blocking or ignoring
<B>SIGTTOU</B>,
a
<B>SIGTTOU</B>
signal is sent to all members of this background process group.
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
When
<I>fd</I>
refers to the controlling terminal of the calling process,
the function
<B>tcgetpgrp</B>()
will return the foreground process group ID of that terminal
if there is one, and some value larger than 1 that is not
presently a process group ID otherwise.
When
<I>fd</I>
does not refer to the controlling terminal of the calling process,
-1 is returned, and
<I>errno</I>
is set appropriately.
<P>
When successful,
<B>tcsetpgrp</B>()
returns 0.
Otherwise, it returns -1, and
<I>errno</I>
is set appropriately.
<A NAME="lbAF">&nbsp;</A>
<H2>ERRORS</H2>
<DL COMPACT>
<DT id="1"><B>EBADF</B>
<DD>
<I>fd</I>
is not a valid file descriptor.
<DT id="2"><B>EINVAL</B>
<DD>
<I>pgrp</I>
has an unsupported value.
<DT id="3"><B>ENOTTY</B>
<DD>
The calling process does not have a controlling terminal, or
it has one but it is not described by
<I>fd</I>,
or, for
<B>tcsetpgrp</B>(),
this controlling terminal is no longer associated with the session
of the calling process.
<DT id="4"><B>EPERM</B>
<DD>
<I>pgrp</I>
has a supported value, but is not the process group ID of a
process in the same session as the calling process.
</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>tcgetpgrp</B>(),
<B>tcsetpgrp</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
</TABLE>
<A NAME="lbAH">&nbsp;</A>
<H2>CONFORMING TO</H2>
POSIX.1-2001, POSIX.1-2008.
<A NAME="lbAI">&nbsp;</A>
<H2>NOTES</H2>
These functions are implemented via the
<B>TIOCGPGRP</B>
and
<B>TIOCSPGRP</B>
ioctls.
<A NAME="lbAJ">&nbsp;</A>
<H3>History</H3>
The ioctls appeared in 4.2BSD.
The functions are POSIX inventions.
<A NAME="lbAK">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?2+setpgid">setpgid</A></B>(2),
<B><A HREF="/cgi-bin/man/man2html?2+setsid">setsid</A></B>(2),
<B><A HREF="/cgi-bin/man/man2html?7+credentials">credentials</A></B>(7)
<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="5"><A HREF="#lbAB">NAME</A><DD>
<DT id="6"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="7"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="8"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DT id="9"><A HREF="#lbAF">ERRORS</A><DD>
<DT id="10"><A HREF="#lbAG">ATTRIBUTES</A><DD>
<DT id="11"><A HREF="#lbAH">CONFORMING TO</A><DD>
<DT id="12"><A HREF="#lbAI">NOTES</A><DD>
<DL>
<DT id="13"><A HREF="#lbAJ">History</A><DD>
</DL>
<DT id="14"><A HREF="#lbAK">SEE ALSO</A><DD>
<DT id="15"><A HREF="#lbAL">COLOPHON</A><DD>
</DL>
<HR>
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