230 lines
7.0 KiB
HTML
230 lines
7.0 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>pthread_get_expiration_np()--Get Condition Expiration Time from Relative Time</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_get_expiration_np()--Get Condition Expiration Time from Relative Time</h2>
|
|
|
|
<div class="box" style="width: 70%;">
|
|
<br>
|
|
Syntax:
|
|
<pre> #include <pthread.h>
|
|
#include <time.h>
|
|
int pthread_get_expiration_np(const struct timespec *delta,
|
|
struct timespec *abstime); </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: Yes<br>
|
|
<!-- iddvc RMBR -->
|
|
<br>
|
|
</div>
|
|
|
|
<p>The <strong>pthread_get_expiration_np</strong>() function computes an absolute time by adding the specified relative time (<em>delta</em>) to the current system time. The resulting absolute time output in the <em>abstime</em> parameter can be used as the expiration time in a call to <strong>pthread_cond_timedwait</strong>().</p>
|
|
|
|
<p>The current system time is retrieved from the system clock.</p>
|
|
|
|
<p><strong>Note:</strong> This function is not portable.</p>
|
|
|
|
<br>
|
|
<h3>Authorities and Locks</h3>
|
|
|
|
<p>None.</p>
|
|
|
|
<br>
|
|
<h3>Parameters</h3>
|
|
|
|
<dl>
|
|
<dt><strong>delta</strong></dt>
|
|
|
|
<dd>(Input) Elapsed time to add to the current system time</dd>
|
|
|
|
<dt><strong>abstime</strong></dt>
|
|
|
|
<dd>(Output) Address of the returned value representing the expiration time</dd>
|
|
</dl>
|
|
|
|
<br>
|
|
<h3>Return Value</h3>
|
|
|
|
<dl>
|
|
<dt><strong>0</strong></dt>
|
|
|
|
<dd><strong>pthread_get_expiration_np</strong>() was successful.</dd>
|
|
|
|
<dt><strong>value</strong></dt>
|
|
|
|
<dd><strong>pthread_get_expiration_np</strong>() was not successful. <em>value</em> is set to indicate the error condition.</dd>
|
|
</dl>
|
|
|
|
<br>
|
|
<h3>Error Conditions</h3>
|
|
|
|
<p>If <strong>pthread_get_expiration_np</strong>() was not successful, the error condition returned usually indicates one of the following errors. Under some conditions, the value returned could indicate an error other than those listed here.</p>
|
|
|
|
<dl>
|
|
<dt><em>[EINVAL]</em></dt>
|
|
|
|
<dd><p>The value specified for the argument is not correct.</p></dd>
|
|
</dl>
|
|
|
|
<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_77.htm">pthread_cond_timedwait()</a>--Timed Wait for Condition</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 <stdio.h>
|
|
#include <qp0z1170.h>
|
|
#include <time.h>
|
|
#include <pthread.h>
|
|
#include "check.h"
|
|
|
|
/* For safe condition variable usage, must use a boolean predicate and */
|
|
/* a mutex with the condition. */
|
|
int workToDo = 0;
|
|
pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
|
|
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
|
|
int failStatus=99;
|
|
|
|
#define NTHREADS 2
|
|
#define WAIT_TIME_SECONDS 3
|
|
|
|
void *threadfunc(void *parm)
|
|
{
|
|
int rc;
|
|
struct timespec delta;
|
|
struct timespec abstime;
|
|
int retries = 2;
|
|
pthread_id_np_t tid;
|
|
|
|
tid = pthread_getthreadid_np();
|
|
|
|
rc = pthread_mutex_lock(&mutex);
|
|
checkResults("pthread_mutex_lock()\n", rc);
|
|
|
|
while (retries--) {
|
|
delta.tv_sec = WAIT_TIME_SECONDS;
|
|
delta.tv_nsec = 0;
|
|
rc = pthread_get_expiration_np(&delta, &abstime);
|
|
checkResults("pthread_get_expiration_np()\n", rc);
|
|
|
|
while (!workToDo) {
|
|
printf("Thread 0x%.8x %.8x blocked\n", tid);
|
|
rc = pthread_cond_timedwait(&cond, &mutex, &abstime);
|
|
if (rc != ETIMEDOUT) {
|
|
printf("pthread_cond_timedwait() - expect timeout %d\n", rc);
|
|
rc = pthread_mutex_unlock(&mutex);
|
|
checkResults("pthread_mutex_lock()\n", rc);
|
|
return __VOID(failStatus);
|
|
}
|
|
/* Since there is no code in this example to wake up any */
|
|
/* thread on the condition variable, we know we are done */
|
|
/* because we have timed out. */
|
|
break;
|
|
}
|
|
printf("Wait timed out! tid=0x%.8x %.8x\n", tid);
|
|
}
|
|
|
|
rc = pthread_mutex_unlock(&mutex);
|
|
checkResults("pthread_mutex_lock()\n", rc);
|
|
return __VOID(0);
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
int rc=0;
|
|
int i;
|
|
pthread_t threadid[NTHREADS];
|
|
void *status;
|
|
int results=0;
|
|
|
|
printf("Enter Testcase - %s\n", argv[0]);
|
|
|
|
printf("Create %d threads\n", NTHREADS);
|
|
for(i=0; i<NTHREADS; ++i) {
|
|
rc = pthread_create(&threadid[i], NULL, threadfunc, NULL);
|
|
checkResults("pthread_create()\n", rc);
|
|
}
|
|
|
|
printf("Wait for threads and cleanup\n");
|
|
for (i=0; i<NTHREADS; ++i) {
|
|
rc = pthread_join(threadid[i], &status);
|
|
checkResults("pthread_join()\n", rc);
|
|
if (__INT(status) == failStatus) {
|
|
printf("A thread failed!\n");
|
|
results++;
|
|
}
|
|
}
|
|
|
|
pthread_cond_destroy(&cond);
|
|
pthread_mutex_destroy(&mutex);
|
|
printf("Main completed\n");
|
|
return results;
|
|
}</pre>
|
|
|
|
<p><strong>Output:</strong></p>
|
|
|
|
<pre>Enter Testcase - QP0WTEST/TPGETEX0
|
|
Create 2 threads
|
|
Wait for threads and cleanup
|
|
Thread 0x00000000 000002ab blocked
|
|
Thread 0x00000000 000002ac blocked
|
|
Wait timed out! tid=0x00000000 000002ab
|
|
Thread 0x00000000 000002ab blocked
|
|
Wait timed out! tid=0x00000000 000002ac
|
|
Thread 0x00000000 000002ac blocked
|
|
Wait timed out! tid=0x00000000 000002ab
|
|
Wait timed out! tid=0x00000000 000002ac
|
|
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>
|