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<H1>SIGSETOPS</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>
sigemptyset, sigfillset, sigaddset, sigdelset, sigismember - POSIX
signal set operations
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<B>#include &lt;<A HREF="file:///usr/include/signal.h">signal.h</A>&gt;</B>
<P>
<B>int sigemptyset(sigset_t *</B><I>set</I><B>);</B>
<P>
<B>int sigfillset(sigset_t *</B><I>set</I><B>);</B>
<P>
<B>int sigaddset(sigset_t *</B><I>set</I><B>, int </B><I>signum</I><B>);</B>
<P>
<B>int sigdelset(sigset_t *</B><I>set</I><B>, int </B><I>signum</I><B>);</B>
<P>
<B>int sigismember(const sigset_t *</B><I>set</I><B>, int </B><I>signum</I><B>);</B>
<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>sigemptyset</B>(),
<B>sigfillset</B>(),
<B>sigaddset</B>(),
<B>sigdelset</B>(),
<B>sigismember</B>():
<DL COMPACT><DT id="1"><DD>
_POSIX_C_SOURCE
</DL>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
These functions allow the manipulation of POSIX signal sets.
<P>
<B>sigemptyset</B>()
initializes the signal set given by
<I>set</I>
to empty, with all signals excluded from the set.
<P>
<B>sigfillset</B>()
initializes
<I>set</I>
to full, including all signals.
<P>
<B>sigaddset</B>()
and
<B>sigdelset</B>()
add and delete respectively signal
<I>signum</I>
from
<I>set</I>.
<P>
<B>sigismember</B>()
tests whether
<I>signum</I>
is a member of
<I>set</I>.
<P>
Objects of type
<I>sigset_t</I>
must be initialized by a call to either
<B>sigemptyset</B>()
or
<B>sigfillset</B>()
before being passed to the functions
<B>sigaddset</B>(),
<B>sigdelset</B>()
and
<B>sigismember</B>()
or the additional glibc functions described below
(<B>sigisemptyset</B>(),
<B>sigandset</B>(),
and
<B>sigorset</B>()).
The results are undefined if this is not done.
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
<B>sigemptyset</B>(),
<B>sigfillset</B>(),
<B>sigaddset</B>(),
and
<B>sigdelset</B>()
return 0 on success and -1 on error.
<P>
<B>sigismember</B>()
returns 1 if
<I>signum</I>
is a member of
<I>set</I>,
0 if
<I>signum</I>
is not a member, and -1 on error.
<P>
On error, these functions set
<I>errno</I>
to indicate the cause of the error.
<A NAME="lbAF">&nbsp;</A>
<H2>ERRORS</H2>
<DL COMPACT>
<DT id="2"><B>EINVAL</B>
<DD>
<I>signum</I>
is not a valid signal.
</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>sigemptyset</B>(),
<B>sigfillset</B>(),
<BR>
<B>sigaddset</B>(),
<B>sigdelset</B>(),
<BR>
<B>sigismember</B>(),
<B>sigisemptyset</B>(),
<BR>
<B>sigorset</B>(),
<B>sigandset</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>
When creating a filled signal set, the glibc
<B>sigfillset</B>()
function does not include the two real-time signals used internally
by the NPTL threading implementation.
See
<B><A HREF="/cgi-bin/man/man2html?7+nptl">nptl</A></B>(7)
for details.
<A NAME="lbAJ">&nbsp;</A>
<H3>Glibc extensions</H3>
If the
<B>_GNU_SOURCE</B>
feature test macro is defined, then <I>&lt;<A HREF="file:///usr/include/signal.h">signal.h</A>&gt;</I>
exposes three other functions for manipulating signal
sets:
<P>
<PRE>
<B>int sigisemptyset(const sigset_t *</B><I>set</I><B>);</B>
<B>int sigorset(sigset_t *</B><I>dest</I><B>, const sigset_t *</B><I>left</I><B>,</B>
<B> const sigset_t *</B><I>right</I><B>);</B>
<B>int sigandset(sigset_t *</B><I>dest</I><B>, const sigset_t *</B><I>left</I><B>,</B>
<B> const sigset_t *</B><I>right</I><B>);</B>
</PRE>
<P>
<B>sigisemptyset</B>()
returns 1 if
<I>set</I>
contains no signals, and 0 otherwise.
<P>
<B>sigorset</B>()
places the union of the sets
<I>left</I>
and
<I>right</I>
in
<I>dest</I>.
<B>sigandset</B>()
places the intersection of the sets
<I>left</I>
and
<I>right</I>
in
<I>dest</I>.
Both functions return 0 on success, and -1 on failure.
<P>
These functions are nonstandard (a few other systems provide similar
functions) and their use should be avoided in portable applications.
<A NAME="lbAK">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?2+sigaction">sigaction</A></B>(2),
<B><A HREF="/cgi-bin/man/man2html?2+sigpending">sigpending</A></B>(2),
<B><A HREF="/cgi-bin/man/man2html?2+sigprocmask">sigprocmask</A></B>(2),
<B><A HREF="/cgi-bin/man/man2html?2+sigsuspend">sigsuspend</A></B>(2)
<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="3"><A HREF="#lbAB">NAME</A><DD>
<DT id="4"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="5"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="6"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DT id="7"><A HREF="#lbAF">ERRORS</A><DD>
<DT id="8"><A HREF="#lbAG">ATTRIBUTES</A><DD>
<DT id="9"><A HREF="#lbAH">CONFORMING TO</A><DD>
<DT id="10"><A HREF="#lbAI">NOTES</A><DD>
<DL>
<DT id="11"><A HREF="#lbAJ">Glibc extensions</A><DD>
</DL>
<DT id="12"><A HREF="#lbAK">SEE ALSO</A><DD>
<DT id="13"><A HREF="#lbAL">COLOPHON</A><DD>
</DL>
<HR>
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