206 lines
5.9 KiB
HTML
206 lines
5.9 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>pthread_testcancel()--Create Cancellation Point</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 ========================================== -->
|
|
<!-- NETMG2 SCRIPT A converted by B2H R4.1 (346) (CMS) by HOLTJM at -->
|
|
<!-- RCHVMW2 on 29 Jan 1999 at 10:01:37 -->
|
|
<!--File Edited November 2001 -->
|
|
<!--End Header Records -->
|
|
<link rel="stylesheet" type="text/css" href="../rzahg/ic.css">
|
|
</head>
|
|
<body>
|
|
|
|
<!-- Java sync-link -->
|
|
<script language="Javascript" src="../rzahg/synch.js" type="text/javascript">
|
|
</script>
|
|
|
|
<a name="Top_Of_Page"></a>
|
|
|
|
<h2>pthread_testcancel()--Create Cancellation Point</h2>
|
|
|
|
<div class="box" style="width: 50%;">
|
|
<br>
|
|
Syntax:
|
|
|
|
<pre>
|
|
#include <pthread.h>
|
|
void pthread_testcancel(void);
|
|
</pre>
|
|
Service Program Name: QP0WPTHR<br>
|
|
<!-- iddvc RMBR -->
|
|
<br>
|
|
Default Public Authority: *USE <br>
|
|
<!-- iddvc RMBR -->
|
|
<br>
|
|
Threadsafe: Yes<br>
|
|
<!-- iddvc RMBR -->
|
|
<br>
|
|
Signal Safe: No<br>
|
|
<!-- iddvc RMBR -->
|
|
<br>
|
|
</div>
|
|
|
|
<p>The <strong>pthread_testcancel</strong>() function creates a cancellation
|
|
point in the calling thread. If cancelability is currently disabled, this
|
|
function has no effect. For more information on cancelability, see <a href=
|
|
"users_38.htm">Thread cancellation APIs</a>.</p>
|
|
|
|
<p>When cancelability is disabled, all cancels are held pending in the target
|
|
thread until the thread changes the cancelability. When cancelability is
|
|
deferred, all cancels are held pending in the target thread until the thread
|
|
changes the cancelability, calls a function that is a cancellation point, or
|
|
calls <strong>pthread_testcancel</strong>(), thus creating a cancellation
|
|
point. When cancelability is asynchronous, all cancels are acted upon
|
|
immediately, interrupting the thread with its processing.</p>
|
|
|
|
<p><strong>Note:</strong> You should not use asynchronous thread cancellation
|
|
through the <strong>PTHREAD_CANCEL_ASYNCHRONOUS</strong> option of <strong>
|
|
pthread_setcanceltype</strong>(). See the common user errors section of this
|
|
document for more information.</p>
|
|
|
|
<br>
|
|
<h3>Authorities and Locks</h3>
|
|
|
|
<p>None.</p>
|
|
|
|
<br>
|
|
<h3>Parameters</h3>
|
|
|
|
<p>None.</p>
|
|
|
|
<br>
|
|
<h3>Return Value</h3>
|
|
|
|
<p>None.</p>
|
|
|
|
<br>
|
|
<h3>Error Conditions</h3>
|
|
|
|
<p>None.</p>
|
|
|
|
<br>
|
|
<h3>Related Information</h3>
|
|
|
|
<ul>
|
|
<li>The <<strong>pthread.h</strong>> header file. See <a href=
|
|
"rzah4hed.htm">Header files for Pthread functions</a>.<br><br></li>
|
|
|
|
<li><a href="users_39.htm">pthread_cancel()</a>--Cancel Thread<br><br></li>
|
|
|
|
<li><a href="users_44.htm">pthread_setcancelstate()</a>--Set Cancel State<br><br></li>
|
|
|
|
<li><a href="users_45.htm">pthread_setcanceltype()</a>--Set Cancel Type</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>
|
|
<pre>
|
|
#define _MULTI_THREADED
|
|
#include <pthread.h>
|
|
#include <stdio.h>
|
|
#include "check.h"
|
|
|
|
void cleanupHandler(void *parm) {
|
|
printf("Inside cancellation cleanup handler\n");
|
|
}
|
|
|
|
void *threadfunc(void *parm)
|
|
{
|
|
unsigned int i=0;
|
|
int rc=0, oldState=0;
|
|
printf("Entered secondary thread\n");
|
|
pthread_cleanup_push(cleanupHandler, NULL);
|
|
rc = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState);
|
|
checkResults("pthread_setcancelstate()\n", rc);
|
|
/* Allow cancel to be pending on this thread */
|
|
sleep(2);
|
|
while (1) {
|
|
printf("Secondary thread is now looping\n");
|
|
++i;
|
|
sleep(1);
|
|
/* pthread_testcancel() has no effect until cancelability is enabled.*/
|
|
/* At that time, a call to pthread_testcancel() should result in the */
|
|
/* pending cancel being acted upon */
|
|
pthread_testcancel();
|
|
if (i == 5) {
|
|
printf("Cancel state set to ENABLE\n");
|
|
rc = pthread_setcancelstate(PTHREAD_CANCEL_ENABLE,&oldState);
|
|
checkResults("pthread_setcancelstate(2)\n", rc);
|
|
/* Now, cancellation points will allow pending cancels
|
|
to get through to this thread */
|
|
}
|
|
} /* infinite */
|
|
pthread_cleanup_pop(0);
|
|
return NULL;
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
pthread_t thread;
|
|
int rc=0;
|
|
void *status=NULL;
|
|
|
|
printf("Enter Testcase - %s\n", argv[0]);
|
|
|
|
/* Create a thread using default attributes */
|
|
printf("Create thread using the NULL attributes\n");
|
|
rc = pthread_create(&thread, NULL, threadfunc, NULL);
|
|
checkResults("pthread_create(NULL)\n", rc);
|
|
|
|
sleep(1);
|
|
printf("Cancel the thread\n");
|
|
rc = pthread_cancel(thread);
|
|
checkResults("pthread_cancel()\n", rc);
|
|
|
|
rc = pthread_join(thread, &status);
|
|
if (status != PTHREAD_CANCELED) {
|
|
printf("Thread returned unexpected result!\n");
|
|
exit(1);
|
|
}
|
|
printf("Main completed\n");
|
|
return 0;
|
|
}
|
|
</pre>
|
|
|
|
<p><strong>Output:</strong></p>
|
|
|
|
<pre>
|
|
Enter Testcase - QP0WTEST/TPTESTC0
|
|
Create thread using the NULL attributes
|
|
Entered secondary thread
|
|
Cancel the thread
|
|
Secondary thread is now looping
|
|
Secondary thread is now looping
|
|
Secondary thread is now looping
|
|
Secondary thread is now looping
|
|
Secondary thread is now looping
|
|
Cancel state set to ENABLE
|
|
Secondary thread is now looping
|
|
Inside cancellation cleanup handler
|
|
Main completed
|
|
</pre>
|
|
<hr>
|
|
API introduced: V4R3
|
|
<hr>
|
|
<center>
|
|
<table cellpadding="2" cellspacing="2">
|
|
<tr align="center">
|
|
<td valign="middle" align="center"><a href="#Top_Of_Page">Top</a> | <a href=
|
|
"rzah4mst.htm">Pthread APIs</a> | <a href="aplist.htm">APIs by
|
|
category</a></td>
|
|
</tr>
|
|
</table>
|
|
</center>
|
|
</body>
|
|
</html>
|
|
|