229 lines
5.6 KiB
HTML
229 lines
5.6 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<meta name="Copyright" content="Copyright (c) 2006 by IBM Corporation">
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<title>gettimeofday()--Get Current UTC Time</title>
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<!-- Begin Header records -->
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<!-- Change History: -->
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<link rel="stylesheet" type="text/css" href="../rzahg/ic.css">
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</head>
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<body>
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<!--End Header Records ================================================ -->
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<!-- Java sync-link =================================================== -->
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<script type="text/javascript" language="Javascript" src="../rzahg/synch.js">
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</script>
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<a name="Top_Of_Page"></a>
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<h2>gettimeofday()--Get Current UTC Time</h2>
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<div class="box" style="width: 60%;">
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<br>
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Syntax<br>
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<pre>
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#include <sys/time.h>
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int gettimeofday (struct timeval *<var>tp</var>,
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struct timezone *<var>tzp</var>);
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</pre>
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<br>
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Service Program Name:QWCTZUTC<br>
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<!-- iddvc RMBR -->
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<br>
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Default Public Authority: *USE<br>
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<!-- iddvc RMBR -->
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<br>
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Threadsafe: Yes<br>
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<!-- iddvc RMBR -->
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<br>
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</div>
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<p>The <strong>gettimeofday()</strong> function retrieves the
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current Coordinated Universal Time (UTC) and places it in the timeval structure pointed
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to by <var>tp</var>. If <var>tzp</var> is not NULL, the time zone information
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is returned in the time zone structure pointed to by <var>tzp</var>.</p>
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<br>
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<h3>Parameters</h3>
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<dl>
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<dt><strong>tp</strong></dt>
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<dd>(Output) A pointer to a timeval structure that contains the time in seconds
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and microseconds since 1 January 1970, 00:00:00 UTC (epoch-1970).<br>
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<br>
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</dd>
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<dt><strong>tzp</strong></dt>
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<dd>(Output) A pointer to a time zone structure that contains the local time
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zone (measured in minutes west of Greenwich) and a flag that, if
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nonzero, indicates Daylight Saving Time applies locally during the appropriate
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part of the year.</dd>
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</dl>
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<br>
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<h3>Authorities and Locks</h3>
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<p>None</p>
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<br>
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<h3>Return Value</h3>
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<table cellpadding="5">
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<!-- cols="5 95" -->
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<tr>
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<td align="left" valign="top"><em>0</em></td>
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<td align="left" valign="top"><strong>gettimeofday()</strong> was
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successful.<br>
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<br>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>-1</em></td>
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<td align="left" valign="top"><strong>gettimeofday()</strong> was not
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successful. The <var>errno</var> variable is set to indicate the error.</td>
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</tr>
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</table>
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<br>
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<br>
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<h3>Error Conditions</h3>
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<p>If <strong>gettimeofday()</strong> is not successful, <var>errno</var>
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usually indicates one of the following errors. Under some conditions,
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<var>errno</var> could indicate an error other than those listed here.</p>
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<table cellpadding="5">
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<!-- cols="15 85" -->
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<tr>
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<td align="left" valign="top"><em>[EINVAL]</em></td>
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<td align="left" valign="top">An invalid parameter was found.
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<p>A parameter passed to this function is not valid.</p>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[EFAULT]</em></td>
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<td align="left" valign="top">The address used for an argument is not correct.
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<p>In attempting to use an argument in a call, the system detected an address
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that is not valid.</p>
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<p>While attempting to access a parameter passed to this function, the system
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detected an address that is not valid.</p>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[EUNKNOWN]</em></td>
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<td align="left" valign="top">Unknown system state.
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<p>The operation failed because of an unknown system state. See any messages in the job log and correct any errors that are indicated, then retry the operation.</p>
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</td>
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</tr>
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</table>
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<br>
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<br>
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<h3>Error Messages</h3>
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<p>None.</p>
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<br>
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<h3>Usage Notes</h3>
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<ul>
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<li>For the best performance, specify NULL for the <var>tzp</var> parameter.</li>
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</ul>
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<br>
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<h3>Related Information</h3>
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<ul>
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<li>The <<strong>sys/time.h</strong>> file (see <a href=
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"unix13.htm">Header Files for UNIX-Type Functions</a>)<br>
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<br>
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</li>
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<li><a href="adjtime.htm">adjtime()--Adjust System Clock</a><br>
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<br>
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</li>
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<li><a href="ftime.htm">ftime()--Get Date and Time</a><br>
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<br>
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</li>
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<li><a href="cvttomit.htm">Qp0zCvtToMITime()--Convert Timeval Structure to _MI_ Time</a><br>
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<br>
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</li>
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<li><a href="settod.htm">settimeofday()--Set System Clock</a></li>
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</ul>
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<br>
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<h3>Example</h3>
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<p>See <a href="../apiref/aboutapis.htm#codedisclaimer">Code disclaimer information</a>
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for information pertaining to code examples.</p>
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<p>The following example gets the current UTC time:</p>
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<pre>
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#include <sys/time.h>
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#include <stdio.h>
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#include <errno.h>
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int main(int argc, char *argv[])
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{
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struct timeval now;
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int rc;
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rc=gettimeofday(&now, NULL);
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if(rc==0) {
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printf("gettimeofday() successful.\n");
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printf("time = %u.%06u\n",
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now.tv_sec, now.tv_usec);
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}
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else {
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printf("gettimeofday() failed, errno = %d\n",
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errno);
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return -1;
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}
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return 0;
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}
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</pre>
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<strong>Example Output:</strong>
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<pre>
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gettimeofday() successful.
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time = 866208142.290944
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</pre>
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<br>
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<hr>
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API introduced: V4R2
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<hr>
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<center>
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<table cellpadding="2" cellspacing="2">
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<tr align="center">
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<td valign="middle" align="center"><a href="#Top_Of_Page">Top</a> | <a href=
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"unix.htm">UNIX-Type APIs</a> | <a href="aplist.htm">APIs by category</a></td>
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</tr>
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</table>
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</center>
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</body>
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</html>
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