308 lines
8.0 KiB
HTML
308 lines
8.0 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
|
<meta name="Copyright" content="Copyright (c) 2006 by IBM Corporation">
|
|
<title>Qp0sEnableSignals()--Enable Process for Signals</title>
|
|
<!-- All rights reserved. Licensed Materials Property of IBM -->
|
|
<!-- US Government Users Restricted Rights -->
|
|
<!-- Use, duplication or disclosure restricted by -->
|
|
<!-- GSA ADP Schedule Contract with IBM Corp. -->
|
|
<!-- Begin Header Records ========================================== -->
|
|
<!-- UNIX5 SCRIPT J converted by B2H R4.1 (346) (CMS) by V2KEA304 -->
|
|
<!-- at RCHVMW2 on 17 Feb 1999 at 11:05:09 -->
|
|
<!-- Edited by Kersten Feb 02 -->
|
|
<!--End Header Records -->
|
|
<link rel="stylesheet" type="text/css" href="../rzahg/ic.css">
|
|
</head>
|
|
<body>
|
|
<a name="Top_Of_Page"></a>
|
|
<!-- Java sync-link -->
|
|
<script type="text/javascript" language="Javascript" src="../rzahg/synch.js">
|
|
</script>
|
|
|
|
<h2>Qp0sEnableSignals()--Enable Process for Signals</h2>
|
|
|
|
<div class="box" style="width: 60%;">
|
|
<br>
|
|
Syntax<br>
|
|
<pre>
|
|
#include <signal.h>
|
|
|
|
int Qp0sEnableSignals( void );
|
|
</pre>
|
|
|
|
<br>
|
|
Service Program Name: QPOSSRV1<br>
|
|
<!-- iddvc RMBR -->
|
|
<br>
|
|
Default Public Authority: *USE<br>
|
|
<!-- iddvc RMBR -->
|
|
<br>
|
|
Threadsafe: Yes<br>
|
|
<!-- iddvc RMBR -->
|
|
<br>
|
|
</div>
|
|
|
|
<p>The <strong>Qp0sEnableSignals()</strong> function enables the process to
|
|
receive signals.</p>
|
|
|
|
<p>The <strong>Qp0sEnableSignals()</strong> function causes the process signal
|
|
vector to be initialized for the set of supported signals. The signal handling
|
|
action for each supported signal is set to the default action, as defined by
|
|
<strong>sigaction()</strong> (see <a href="sigactn.htm">sigaction()--Examine
|
|
and Change Signal Action</a>). The signal blocking mask of the calling thread
|
|
is set to the empty signal set (see <a href="sigeset.htm">
|
|
sigemptyset()--Initialize and Empty Signal Set</a>).</p>
|
|
|
|
<p>If the process is currently enabled for signals, a call to the <strong>
|
|
Qp0sEnableSignals()</strong> has no effect. That is, the process signal vector
|
|
and the signal blocking mask of the calling thread are unchanged and an
|
|
[EALREADY] error is returned.</p>
|
|
|
|
<br>
|
|
<!-- Please NOTE: DO NOT DELETE THIS SECTION if this API has no authorities and locks. -->
|
|
<!-- Instead, use the commented out coding below to indicate NONE. -->
|
|
<h3>Authorities and Locks</h3>
|
|
|
|
<!-- Use this if there are no authorities and locks. -->
|
|
<p>None.</p>
|
|
|
|
<br>
|
|
<h3>Parameters</h3>
|
|
|
|
<p>None</p>
|
|
|
|
<br>
|
|
<h3>Return Value</h3>
|
|
|
|
<table cellpadding="5">
|
|
<!-- cols="5 95" -->
|
|
<tr>
|
|
<td align="left" valign="top"><em>0</em></td>
|
|
<td align="left" valign="top"><strong>Qp0sEnableSignals()</strong> was
|
|
successful.</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>-1</em></td>
|
|
<td align="left" valign="top"><strong>Qp0sEnableSignals()</strong> was not
|
|
successful. The <em>errno</em> variable is set to indicate the error.</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<br>
|
|
<br>
|
|
<h3>Error Conditions</h3>
|
|
|
|
<p>If <strong>Qp0sEnableSignals()</strong> is not successful, <em>errno</em>
|
|
usually indicates one of the following errors. Under some conditions, <em>
|
|
errno</em> could indicate an error other than those listed here.</p>
|
|
|
|
<dl>
|
|
<dt><em>[EALREADY]</em></dt>
|
|
|
|
<dd>
|
|
<p>Operation already in progress.</p>
|
|
|
|
<p>The calling process is currently enabled for signals.</p>
|
|
</dd>
|
|
|
|
<dt><em>[ENOTSIGINIT]</em></dt>
|
|
|
|
<dd>
|
|
<p>Process not enabled for signals.</p>
|
|
|
|
<p>An attempt was made to call a signal function under one of the following
|
|
conditions:</p>
|
|
|
|
<ul>
|
|
<li>The signal function is being called for a process that is not enabled for
|
|
asynchronous signals.</li>
|
|
|
|
<li>The signal function is being called when the system signal controls have
|
|
not been initialized.</li>
|
|
|
|
<li style="list-style: none"><br>
|
|
</li>
|
|
</ul>
|
|
</dd>
|
|
</dl>
|
|
|
|
<br>
|
|
<h3>Usage Notes</h3>
|
|
|
|
<ol>
|
|
<li>Processes, by default, are not eligible to receive signals from other
|
|
processes or the system. The <strong>Qp0sEnableSignals</strong>() function
|
|
allows the calling process to receive signals from other processes or the
|
|
system without having to call other signal functions that enable the process
|
|
for signals.
|
|
|
|
<p>Use of the following functions enable a process for signals:</p>
|
|
|
|
<ul>
|
|
<li>alarm()</li>
|
|
|
|
<li>getpgrp()</li>
|
|
|
|
<li>getpid()</li>
|
|
|
|
<li>kill()</li>
|
|
|
|
<li>pause()</li>
|
|
|
|
<li>Qp0wGetPgrp()</li>
|
|
|
|
<li>Qp0wGetPid()</li>
|
|
|
|
<li>setitimer()</li>
|
|
|
|
<li>sigaction()</li>
|
|
|
|
<li>sigprocmask()</li>
|
|
|
|
<li>sigsuspend()</li>
|
|
|
|
<li>sigtimedwait()</li>
|
|
|
|
<li>sigwait()</li>
|
|
|
|
<li>sigwaitinfo()</li>
|
|
|
|
<li>sleep()</li>
|
|
</ul>
|
|
|
|
<p>Any of the Pthread APIs. See <a href="rzah4mst.htm">Pthread APIs</a> for
|
|
more information.</p>
|
|
</li>
|
|
|
|
<li>Once a process has been enabled for signals, it remains eligible to receive
|
|
signals until either it ends or some user action is taken to prevent the
|
|
delivery of signals. The user of signals can prevent the signals from being
|
|
delivered by calling the <strong>sigprocmask()</strong> function. The user can
|
|
also ignore the signal by calling the <strong>sigaction()</strong> function.
|
|
However, not all signals can be blocked or ignored. For details, see <a href=
|
|
"sigactn.htm">sigaction()--Examine and Change Signal Action</a> and <a href=
|
|
"sigpmsk.htm">sigprocmask()--Examine and Change Blocked Signals</a>.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>If a process has not been enabled for signals, the signal blocking mask for
|
|
any thread created in the process will be set to the empty set.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>If a process with multiple threads is disabled for signals by calling
|
|
<strong>Qp0sDisableSignals()</strong> and then later re-enabled for signals,
|
|
only the thread that causes signals to be enabled will have its signal blocking
|
|
mask changed. The signal blocking mask for all other threads will be the value
|
|
last used to set the signal blocking mask for those threads.</li>
|
|
</ol>
|
|
|
|
<br>
|
|
<h3>Related Information</h3>
|
|
|
|
<ul>
|
|
<li>The <<strong>signal.h</strong>> file (see <a href="unix13.htm">Header
|
|
Files for UNIX-Type Functions</a>)<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sigalarm.htm">alarm()</a>--Set Schedule for Alarm Signal<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sigkill.htm">kill()</a>--Send Signal to Process or Group of
|
|
Processes<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sigpause.htm">pause()</a>--Suspend Process Until Signal
|
|
Received<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sigdsig.htm">Qp0sDisableSignals()</a>--Disable Process for
|
|
Signals<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="setitime.htm">setitimer()</a>--Set Value for Interval Timer<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sigactn.htm">sigaction()</a>--Examine and Change Signal Action<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sigpmsk.htm">sigprocmask()</a>--Examine and Change Blocked
|
|
Signals<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sigsusp.htm">sigsuspend()</a>--Wait for Signal<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sigtwait.htm">sigtimedwait()</a>--Synchronously Accept a Signal
|
|
for Interval of Time<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sigwait.htm">sigwait()</a>--Synchronously Accept a Signal<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sigwaiti.htm">sigwaitinfo()</a>--Synchronously Accept a Signal and
|
|
Signal Data<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sigsleep.htm">sleep()</a>--Suspend Processing for Interval of
|
|
Time</li>
|
|
</ul>
|
|
|
|
<br>
|
|
<h3>Example</h3>
|
|
|
|
<p>See <a href="../apiref/aboutapis.htm#codedisclaimer">Code disclaimer information</a>
|
|
for information pertaining to code examples.</p>
|
|
|
|
<p>The following example shows how a process can reset its signal vector and
|
|
signal blocking mask:</p>
|
|
|
|
<pre>
|
|
#include <signal.h>
|
|
#include <errno.h>
|
|
|
|
int resetSignals( void ) {
|
|
|
|
int return_value;
|
|
|
|
return_value = Qp0sEnableSignals();
|
|
if( return_value == -1 ) {
|
|
Qp0sDisableSignals();
|
|
return_value = Qp0sEnableSignals();
|
|
}
|
|
return( return_value );
|
|
}
|
|
</pre>
|
|
|
|
<br>
|
|
<hr>
|
|
API introduced: V3R6
|
|
|
|
<hr>
|
|
<center>
|
|
<table cellpadding="2" cellspacing="2">
|
|
<tr align="center">
|
|
<td valign="middle" align="center"><a href="#Top_Of_Page">Top</a> | <a href=
|
|
"unix.htm">UNIX-Type APIs</a> | <a href="aplist.htm">APIs by category</a></td>
|
|
</tr>
|
|
</table>
|
|
</center>
|
|
</body>
|
|
</html>
|
|
|