man-pages/man3/sigpause.3.html
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<H1>SIGPAUSE</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>
sigpause - atomically release blocked signals and wait for interrupt
<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>int sigpause(int </B><I>sigmask</I><B>); /* BSD (but see NOTES) */</B>
<B>int sigpause(int </B><I>sig</I><B>); /* System V / UNIX 95 */</B>
</PRE>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
Don't use this function.
Use
<B><A HREF="/cgi-bin/man/man2html?2+sigsuspend">sigsuspend</A></B>(2)
instead.
<P>
The function
<B>sigpause</B>()
is designed to wait for some signal.
It changes the process's signal mask (set of blocked signals),
and then waits for a signal to arrive.
Upon arrival of a signal, the original signal mask is restored.
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
If
<B>sigpause</B>()
returns, it was interrupted by a signal and the return value is -1
with
<I>errno</I>
set to
<B>EINTR</B>.
<A NAME="lbAF">&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>sigpause</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
</TABLE>
<A NAME="lbAG">&nbsp;</A>
<H2>CONFORMING TO</H2>
The System V version of
<B>sigpause</B>()
is standardized in POSIX.1-2001.
It is also specified in POSIX.1-2008, where it is marked obsolete.
<A NAME="lbAH">&nbsp;</A>
<H2>NOTES</H2>
<A NAME="lbAI">&nbsp;</A>
<H3>History</H3>
The classical BSD version of this function appeared in 4.2BSD.
It sets the process's signal mask to
<I>sigmask</I>.
UNIX 95 standardized the incompatible System V version of
this function, which removes only the specified signal
<I>sig</I>
from the process's signal mask.
The unfortunate situation with two incompatible functions with the
same name was solved by the
<B><A HREF="/cgi-bin/man/man2html?2+sigsuspend">sigsuspend</A></B>(2)
function, that takes a
<I>sigset_t&nbsp;*</I>
argument (instead of an
<I>int</I>).
<A NAME="lbAJ">&nbsp;</A>
<H3>Linux notes</H3>
On Linux, this routine is a system call only on the Sparc (sparc64)
architecture.
<P>
Glibc uses the BSD version if the
<B>_BSD_SOURCE</B>
feature test macro is defined and none of
<B>_POSIX_SOURCE</B>,
<B>_POSIX_C_SOURCE</B>,
<B>_XOPEN_SOURCE</B>,
<B>_GNU_SOURCE</B>,
or
<B>_SVID_SOURCE</B>
is defined.
Otherwise, the System V version is used,
and feature test macros must be defined as follows to obtain the declaration:
<DL COMPACT>
<DT id="1">*<DD>
Since glibc 2.26:
_XOPEN_SOURCE &gt;= 500
<DT id="2">*<DD>
Glibc 2.25 and earlier: _XOPEN_SOURCE
</DL>
<P>
Since glibc 2.19, only the System V version is exposed by
<I>&lt;<A HREF="file:///usr/include/signal.h">signal.h</A>&gt;</I>;
applications that formerly used the BSD
<B>sigpause</B>()
should be amended to use
<B><A HREF="/cgi-bin/man/man2html?2+sigsuspend">sigsuspend</A></B>(2).
<A NAME="lbAK">&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+sigaction">sigaction</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),
<B><A HREF="/cgi-bin/man/man2html?3+sigblock">sigblock</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+sigvec">sigvec</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</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="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">ATTRIBUTES</A><DD>
<DT id="8"><A HREF="#lbAG">CONFORMING TO</A><DD>
<DT id="9"><A HREF="#lbAH">NOTES</A><DD>
<DL>
<DT id="10"><A HREF="#lbAI">History</A><DD>
<DT id="11"><A HREF="#lbAJ">Linux notes</A><DD>
</DL>
<DT id="12"><A HREF="#lbAK">SEE ALSO</A><DD>
<DT id="13"><A HREF="#lbAL">COLOPHON</A><DD>
</DL>
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