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sigsuspend.html
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<!-- Creator : groff version 1.22.4 -->
<!-- CreationDate: Wed Jan 29 11:26:59 2020 -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta name="generator" content="groff -Thtml, see www.gnu.org">
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<meta name="Content-Style" content="text/css">
<style type="text/css">
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<title>SIGSUSPEND</title>
</head>
<body>
<h1 align="center">SIGSUSPEND</h1>
<a href="#NAME">NAME</a><br>
<a href="#SYNOPSIS">SYNOPSIS</a><br>
<a href="#DESCRIPTION">DESCRIPTION</a><br>
<a href="#RETURN VALUE">RETURN VALUE</a><br>
<a href="#ERRORS">ERRORS</a><br>
<a href="#CONFORMING TO">CONFORMING TO</a><br>
<a href="#NOTES">NOTES</a><br>
<a href="#SEE ALSO">SEE ALSO</a><br>
<a href="#COLOPHON">COLOPHON</a><br>
<hr>
<h2>NAME
<a name="NAME"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">sigsuspend,
rt_sigsuspend - wait for a signal</p>
<h2>SYNOPSIS
<a name="SYNOPSIS"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>#include
<signal.h></b></p>
<p style="margin-left:11%; margin-top: 1em"><b>int
sigsuspend(const sigset_t *</b><i>mask</i><b>);</b></p>
<p style="margin-left:5%; margin-top: 1em">Feature Test
Macro Requirements for glibc (see
<b>feature_test_macros</b>(7)):</p>
<p style="margin-left:11%; margin-top: 1em"><b>sigsuspend</b>():
_POSIX_C_SOURCE</p>
<h2>DESCRIPTION
<a name="DESCRIPTION"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>sigsuspend</b>()
temporarily replaces the signal mask of the calling thread
with the mask given by <i>mask</i> and then suspends the
thread until delivery of a signal whose action is to invoke
a signal handler or to terminate a process.</p>
<p style="margin-left:11%; margin-top: 1em">If the signal
terminates the process, then <b>sigsuspend</b>() does not
return. If the signal is caught, then <b>sigsuspend</b>()
returns after the signal handler returns, and the signal
mask is restored to the state before the call to
<b>sigsuspend</b>().</p>
<p style="margin-left:11%; margin-top: 1em">It is not
possible to block <b>SIGKILL</b> or <b>SIGSTOP</b>;
specifying these signals in <i>mask</i>, has no effect on
the thread’s signal mask.</p>
<h2>RETURN VALUE
<a name="RETURN VALUE"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>sigsuspend</b>()
always returns -1, with <i>errno</i> set to indicate the
error (normally, <b>EINTR</b>).</p>
<h2>ERRORS
<a name="ERRORS"></a>
</h2>
<table width="100%" border="0" rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p style="margin-top: 1em"><b>EFAULT</b></p></td>
<td width="2%"></td>
<td width="78%">
<p style="margin-top: 1em"><i>mask</i> points to memory
which is not a valid part of the process address space.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>EINTR</b></p></td>
<td width="2%"></td>
<td width="78%">
<p>The call was interrupted by a signal;
<b>signal</b>(7).</p> </td></tr>
</table>
<h2>CONFORMING TO
<a name="CONFORMING TO"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">POSIX.1-2001,
POSIX.1-2008.</p>
<h2>NOTES
<a name="NOTES"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">Normally,
<b>sigsuspend</b>() is used in conjunction with
<b>sigprocmask</b>(2) in order to prevent delivery of a
signal during the execution of a critical code section. The
caller first blocks the signals with <b>sigprocmask</b>(2).
When the critical code has completed, the caller then waits
for the signals by calling <b>sigsuspend</b>() with the
signal mask that was returned by <b>sigprocmask</b>(2) (in
the <i>oldset</i> argument).</p>
<p style="margin-left:11%; margin-top: 1em">See
<b>sigsetops</b>(3) for details on manipulating signal
sets.</p>
<p style="margin-left:11%; margin-top: 1em"><b>C
library/kernel differences</b> <br>
The original Linux system call was named
<b>sigsuspend</b>(). However, with the addition of real-time
signals in Linux 2.2, the fixed-size, 32-bit <i>sigset_t</i>
type supported by that system call was no longer fit for
purpose. Consequently, a new system call,
<b>rt_sigsuspend</b>(), was added to support an enlarged
<i>sigset_t</i> type. The new system call takes a second
argument, <i>size_t sigsetsize</i>, which specifies the size
in bytes of the signal set in <i>mask</i>. This argument is
currently required to have the value <i>sizeof(sigset_t)</i>
(or the error <b>EINVAL</b> results). The glibc
<b>sigsuspend</b>() wrapper function hides these details
from us, transparently calling <b>rt_sigsuspend</b>() when
the kernel provides it.</p>
<h2>SEE ALSO
<a name="SEE ALSO"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>kill</b>(2),
<b>pause</b>(2), <b>sigaction</b>(2), <b>signal</b>(2),
<b>sigprocmask</b>(2), <b>sigwaitinfo</b>(2),
<b>sigsetops</b>(3), <b>sigwait</b>(3), <b>signal</b>(7)</p>
<h2>COLOPHON
<a name="COLOPHON"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">This page is
part of release 5.02 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
https://www.kernel.org/doc/man-pages/.</p>
<hr>
</body>
</html>