198 lines
8.2 KiB
HTML
198 lines
8.2 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<html>
|
|
<head>
|
|
<meta name="generator" content="HTML Tidy, see www.w3.org">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
|
|
<link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 -->
|
|
<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
|
|
<title>sighold</title>
|
|
</head>
|
|
<body bgcolor="white">
|
|
<script type="text/javascript" language="JavaScript" src="../jscript/codes.js">
|
|
</script>
|
|
|
|
<basefont size="3"> <a name="sighold"></a> <a name="tag_03_686"></a><!-- sighold -->
|
|
<!--header start-->
|
|
<center><font size="2">The Open Group Base Specifications Issue 6<br>
|
|
IEEE Std 1003.1-2001<br>
|
|
Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
|
|
|
|
<!--header end-->
|
|
<hr size="2" noshade>
|
|
<h4><a name="tag_03_686_01"></a>NAME</h4>
|
|
|
|
<blockquote>sighold, sigignore, sigpause, sigrelse, sigset - signal management</blockquote>
|
|
|
|
<h4><a name="tag_03_686_02"></a>SYNOPSIS</h4>
|
|
|
|
<blockquote class="synopsis">
|
|
<div class="box"><code><tt><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt=
|
|
"[Option Start]" border="0"> #include <<a href="../basedefs/signal.h.html">signal.h</a>><br>
|
|
<br>
|
|
int sighold(int</tt> <i>sig</i><tt>);<br>
|
|
int sigignore(int</tt> <i>sig</i><tt>);<br>
|
|
int sigpause(int</tt> <i>sig</i><tt>);<br>
|
|
int sigrelse(int</tt> <i>sig</i><tt>);<br>
|
|
void (*sigset(int</tt> <i>sig</i><tt>, void (*</tt><i>disp</i><tt>)(int)))(int); <img src="../images/opt-end.gif" alt=
|
|
"[Option End]" border="0"></tt></code></div>
|
|
|
|
<tt><br>
|
|
</tt></blockquote>
|
|
|
|
<h4><a name="tag_03_686_03"></a>DESCRIPTION</h4>
|
|
|
|
<blockquote>
|
|
<p>Use of any of these functions is unspecified in a multi-threaded process.</p>
|
|
|
|
<p>The <i>sighold</i>(), <i>sigignore</i>(), <i>sigpause</i>(), <i>sigrelse</i>(), and <i>sigset</i>() functions provide simplified
|
|
signal management.</p>
|
|
|
|
<p>The <i>sigset</i>() function shall modify signal dispositions. The <i>sig</i> argument specifies the signal, which may be any
|
|
signal except SIGKILL and SIGSTOP. The <i>disp</i> argument specifies the signal's disposition, which may be SIG_DFL, SIG_IGN, or
|
|
the address of a signal handler. If <i>sigset</i>() is used, and <i>disp</i> is the address of a signal handler, the system shall
|
|
add <i>sig</i> to the calling process' signal mask before executing the signal handler; when the signal handler returns, the system
|
|
shall restore the calling process' signal mask to its state prior to the delivery of the signal. In addition, if <i>sigset</i>() is
|
|
used, and <i>disp</i> is equal to SIG_HOLD, <i>sig</i> shall be added to the calling process' signal mask and <i>sig</i>'s
|
|
disposition shall remain unchanged. If <i>sigset</i>() is used, and <i>disp</i> is not equal to SIG_HOLD, <i>sig</i> shall be
|
|
removed from the calling process' signal mask.</p>
|
|
|
|
<p>The <i>sighold</i>() function shall add <i>sig</i> to the calling process' signal mask.</p>
|
|
|
|
<p>The <i>sigrelse</i>() function shall remove <i>sig</i> from the calling process' signal mask.</p>
|
|
|
|
<p>The <i>sigignore</i>() function shall set the disposition of <i>sig</i> to SIG_IGN.</p>
|
|
|
|
<p>The <i>sigpause</i>() function shall remove <i>sig</i> from the calling process' signal mask and suspend the calling process
|
|
until a signal is received. The <i>sigpause</i>() function shall restore the process' signal mask to its original state before
|
|
returning.</p>
|
|
|
|
<p>If the action for the SIGCHLD signal is set to SIG_IGN, child processes of the calling processes shall not be transformed into
|
|
zombie processes when they terminate. If the calling process subsequently waits for its children, and the process has no
|
|
unwaited-for children that were transformed into zombie processes, it shall block until all of its children terminate, and <a href=
|
|
"../functions/wait.html"><i>wait</i>()</a>, <a href="../functions/waitid.html"><i>waitid</i>()</a>, and <a href=
|
|
"../functions/waitpid.html"><i>waitpid</i>()</a> shall fail and set <i>errno</i> to [ECHILD].</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_686_04"></a>RETURN VALUE</h4>
|
|
|
|
<blockquote>
|
|
<p>Upon successful completion, <i>sigset</i>() shall return SIG_HOLD if the signal had been blocked and the signal's previous
|
|
disposition if it had not been blocked. Otherwise, SIG_ERR shall be returned and <i>errno</i> set to indicate the error.</p>
|
|
|
|
<p>The <i>sigpause</i>() function shall suspend execution of the thread until a signal is received, whereupon it shall return -1
|
|
and set <i>errno</i> to [EINTR].</p>
|
|
|
|
<p>For all other functions, upon successful completion, 0 shall be returned. Otherwise, -1 shall be returned and <i>errno</i> set
|
|
to indicate the error.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_686_05"></a>ERRORS</h4>
|
|
|
|
<blockquote>
|
|
<p>These functions shall fail if:</p>
|
|
|
|
<dl compact>
|
|
<dt>[EINVAL]</dt>
|
|
|
|
<dd>The <i>sig</i> argument is an illegal signal number.</dd>
|
|
</dl>
|
|
|
|
<p>The <i>sigset</i>() and <i>sigignore</i>() functions shall fail if:</p>
|
|
|
|
<dl compact>
|
|
<dt>[EINVAL]</dt>
|
|
|
|
<dd>An attempt is made to catch a signal that cannot be caught, or to ignore a signal that cannot be ignored.</dd>
|
|
</dl>
|
|
</blockquote>
|
|
|
|
<hr>
|
|
<div class="box"><em>The following sections are informative.</em></div>
|
|
|
|
<h4><a name="tag_03_686_06"></a>EXAMPLES</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_686_07"></a>APPLICATION USAGE</h4>
|
|
|
|
<blockquote>
|
|
<p>The <a href="../functions/sigaction.html"><i>sigaction</i>()</a> function provides a more comprehensive and reliable mechanism
|
|
for controlling signals; new applications should use <a href="../functions/sigaction.html"><i>sigaction</i>()</a> rather than
|
|
<i>sigset</i>().</p>
|
|
|
|
<p>The <i>sighold</i>() function, in conjunction with <i>sigrelse</i>() or <i>sigpause</i>(), may be used to establish critical
|
|
regions of code that require the delivery of a signal to be temporarily deferred.</p>
|
|
|
|
<p>The <a href="../functions/sigsuspend.html"><i>sigsuspend</i>()</a> function should be used in preference to <i>sigpause</i>()
|
|
for broader portability.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_686_08"></a>RATIONALE</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_686_09"></a>FUTURE DIRECTIONS</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_686_10"></a>SEE ALSO</h4>
|
|
|
|
<blockquote>
|
|
<p><a href="xsh_chap02_04.html#tag_02_04"><i>Signal Concepts</i></a> , <a href="exec.html"><i><a href=
|
|
"../functions/exec.html">exec</a></i>()</a> , <a href="pause.html"><i>pause</i>()</a> , <a href=
|
|
"sigaction.html"><i>sigaction</i>()</a> , <a href="signal.html"><i>signal</i>()</a> , <a href=
|
|
"sigsuspend.html"><i>sigsuspend</i>()</a> , <a href="waitid.html"><i>waitid</i>()</a> , the Base Definitions volume of
|
|
IEEE Std 1003.1-2001, <a href="../basedefs/signal.h.html"><i><signal.h></i></a></p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_686_11"></a>CHANGE HISTORY</h4>
|
|
|
|
<blockquote>
|
|
<p>First released in Issue 4, Version 2.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_686_12"></a>Issue 5</h4>
|
|
|
|
<blockquote>
|
|
<p>Moved from X/OPEN UNIX extension to BASE.</p>
|
|
|
|
<p>The DESCRIPTION is updated to indicate that the <i>sigpause</i>() function restores the process' signal mask to its original
|
|
state before returning.</p>
|
|
|
|
<p>The RETURN VALUE section is updated to indicate that the <i>sigpause</i>() function suspends execution of the process until a
|
|
signal is received, whereupon it returns -1 and sets <i>errno</i> to [EINTR].</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_03_686_13"></a>Issue 6</h4>
|
|
|
|
<blockquote>
|
|
<p>The DESCRIPTION is updated to avoid use of the term "must" for application requirements.</p>
|
|
|
|
<p>References to the <i>wait3</i>() function are removed.</p>
|
|
|
|
<p>The XSI functions are split out into their own reference page.</p>
|
|
</blockquote>
|
|
|
|
<div class="box"><em>End of informative text.</em></div>
|
|
|
|
<hr>
|
|
<hr size="2" noshade>
|
|
<center><font size="2"><!--footer start-->
|
|
UNIX ® is a registered Trademark of The Open Group.<br>
|
|
POSIX ® is a registered Trademark of The IEEE.<br>
|
|
[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href=
|
|
"../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>
|
|
]</font></center>
|
|
|
|
<!--footer end-->
|
|
<hr size="2" noshade>
|
|
</body>
|
|
</html>
|
|
|