168 lines
4.0 KiB
HTML
168 lines
4.0 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML><HEAD><TITLE>Man page of SYSV_SIGNAL</TITLE>
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</HEAD><BODY>
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<H1>SYSV_SIGNAL</H1>
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Section: Linux Programmer's Manual (3)<BR>Updated: 2017-09-15<BR><A HREF="#index">Index</A>
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<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
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<A NAME="lbAB"> </A>
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<H2>NAME</H2>
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sysv_signal - signal handling with System V semantics
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<B>#define _GNU_SOURCE</B> /* See <A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</A>(7) */
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<BR>
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<B>#include <<A HREF="file:///usr/include/signal.h">signal.h</A>></B>
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<P>
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<B>typedef void (*sighandler_t)(int);</B>
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<P>
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<B>sighandler_t sysv_signal(int </B><I>signum</I><B>, sighandler_t </B><I>handler</I><B>);</B>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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The
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<B>sysv_signal</B>()
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function takes the same arguments, and performs the same task, as
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<B><A HREF="/cgi-bin/man/man2html?2+signal">signal</A></B>(2).
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<P>
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However
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<B>sysv_signal</B>()
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provides the System V unreliable signal semantics, that is:
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a) the disposition of the signal is reset to the default
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when the handler is invoked;
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b) delivery of further instances of the signal is not blocked while
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the signal handler is executing; and
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c) if the handler interrupts (certain) blocking system calls,
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then the system call is not automatically restarted.
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<A NAME="lbAE"> </A>
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<H2>RETURN VALUE</H2>
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The
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<B>sysv_signal</B>()
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function returns the previous value of the signal handler, or
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<B>SIG_ERR</B>
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on error.
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<A NAME="lbAF"> </A>
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<H2>ERRORS</H2>
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As for
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<B><A HREF="/cgi-bin/man/man2html?2+signal">signal</A></B>(2).
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<A NAME="lbAG"> </A>
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<H2>ATTRIBUTES</H2>
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For an explanation of the terms used in this section, see
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<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
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<TABLE BORDER>
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<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
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<TR VALIGN=top><TD>
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<B>sysv_signal</B>()
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</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
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</TABLE>
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<A NAME="lbAH"> </A>
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<H2>CONFORMING TO</H2>
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This function is nonstandard.
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<A NAME="lbAI"> </A>
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<H2>NOTES</H2>
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Use of
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<B>sysv_signal</B>()
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should be avoided; use
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<B><A HREF="/cgi-bin/man/man2html?2+sigaction">sigaction</A></B>(2)
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instead.
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<P>
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On older Linux systems,
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<B>sysv_signal</B>()
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and
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<B><A HREF="/cgi-bin/man/man2html?2+signal">signal</A></B>(2)
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were equivalent.
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But on newer systems,
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<B><A HREF="/cgi-bin/man/man2html?2+signal">signal</A></B>(2)
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provides reliable signal semantics; see
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<B><A HREF="/cgi-bin/man/man2html?2+signal">signal</A></B>(2)
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for details.
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<P>
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The use of
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<I>sighandler_t</I>
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is a GNU extension;
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this type is defined only if
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the
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<B>_GNU_SOURCE</B>
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feature test macro is defined.
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<A NAME="lbAJ"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?2+sigaction">sigaction</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?2+signal">signal</A></B>(2),
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<B><A HREF="/cgi-bin/man/man2html?3+bsd_signal">bsd_signal</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?7+signal">signal</A></B>(7)
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<A NAME="lbAK"> </A>
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<H2>COLOPHON</H2>
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This page is part of release 5.05 of the Linux
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<I>man-pages</I>
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project.
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A description of the project,
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information about reporting bugs,
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and the latest version of this page,
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can be found at
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<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
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<P>
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<HR>
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<A NAME="index"> </A><H2>Index</H2>
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<DL>
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<DT id="1"><A HREF="#lbAB">NAME</A><DD>
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<DT id="2"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="3"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="4"><A HREF="#lbAE">RETURN VALUE</A><DD>
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<DT id="5"><A HREF="#lbAF">ERRORS</A><DD>
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<DT id="6"><A HREF="#lbAG">ATTRIBUTES</A><DD>
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<DT id="7"><A HREF="#lbAH">CONFORMING TO</A><DD>
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<DT id="8"><A HREF="#lbAI">NOTES</A><DD>
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<DT id="9"><A HREF="#lbAJ">SEE ALSO</A><DD>
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<DT id="10"><A HREF="#lbAK">COLOPHON</A><DD>
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</DL>
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<HR>
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This document was created by
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<A HREF="/cgi-bin/man/man2html">man2html</A>,
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using the manual pages.<BR>
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Time: 00:05:58 GMT, March 31, 2021
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