man-pages/man3/gsignal.3.html
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<H1>GSIGNAL</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>
gsignal, ssignal - software signal facility
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<PRE>
<B>#include &lt;<A HREF="file:///usr/include/signal.h">signal.h</A>&gt;</B>
<B>typedef void (*sighandler_t)(int);</B>
<B>int gsignal(int </B><I>signum</I><B>);</B>
<B>sighandler_t ssignal(int </B><I>signum</I><B>, sighandler_t </B><I>action</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>gsignal</B>(),
<B>ssignal</B>():
<BR>&nbsp;&nbsp;&nbsp;&nbsp;Since&nbsp;glibc&nbsp;2.19:
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;_DEFAULT_SOURCE
<BR>&nbsp;&nbsp;&nbsp;&nbsp;Glibc&nbsp;2.19&nbsp;and&nbsp;earlier:
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;_SVID_SOURCE
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
Don't use these functions under Linux.
Due to a historical mistake, under Linux these functions are
aliases for
<B><A HREF="/cgi-bin/man/man2html?3+raise">raise</A></B>(3)
and
<B><A HREF="/cgi-bin/man/man2html?2+signal">signal</A></B>(2),
respectively.
<P>
Elsewhere, on System V-like systems, these functions implement
software signaling, entirely independent of the classical
<B><A HREF="/cgi-bin/man/man2html?2+signal">signal</A></B>(2)
and
<B><A HREF="/cgi-bin/man/man2html?2+kill">kill</A></B>(2)
functions.
The function
<B>ssignal</B>()
defines the action to take when the software signal with
number
<I>signum</I>
is raised using the function
<B>gsignal</B>(),
and returns the previous such action or
<B>SIG_DFL</B>.
The function
<B>gsignal</B>()
does the following: if no action (or the action
<B>SIG_DFL</B>)
was
specified for
<I>signum</I>,
then it does nothing and returns 0.
If the action
<B>SIG_IGN</B>
was specified for
<I>signum</I>,
then it does nothing and returns 1.
Otherwise, it resets the action to
<B>SIG_DFL</B>
and calls
the action function with argument
<I>signum</I>,
and returns the value returned by that function.
The range of possible values
<I>signum</I>
varies (often 1-15 or 1-17).
<A NAME="lbAE">&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>gsignal</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
<TR VALIGN=top><TD>
<B>ssignal</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe sigintr<BR></TD></TR>
</TABLE>
<P>
<A NAME="lbAF">&nbsp;</A>
<H2>CONFORMING TO</H2>
These functions are available under AIX, DG/UX, HP-UX, SCO, Solaris, Tru64.
They are called obsolete under most of these systems, and are
broken under Linux libc and glibc.
Some systems also have
<B>gsignal_r</B>()
and
<B>ssignal_r</B>().
<A NAME="lbAG">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?2+kill">kill</A></B>(2),
<B><A HREF="/cgi-bin/man/man2html?2+signal">signal</A></B>(2),
<B><A HREF="/cgi-bin/man/man2html?3+raise">raise</A></B>(3)
<A NAME="lbAH">&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">ATTRIBUTES</A><DD>
<DT id="5"><A HREF="#lbAF">CONFORMING TO</A><DD>
<DT id="6"><A HREF="#lbAG">SEE ALSO</A><DD>
<DT id="7"><A HREF="#lbAH">COLOPHON</A><DD>
</DL>
<HR>
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