1<html lang="en"> 2<head> 3<title>mktime - Untitled</title> 4<meta http-equiv="Content-Type" content="text/html"> 5<meta name="description" content="Untitled"> 6<meta name="generator" content="makeinfo 4.13"> 7<link title="Top" rel="start" href="index.html#Top"> 8<link rel="up" href="Timefns.html#Timefns" title="Timefns"> 9<link rel="prev" href="localtime.html#localtime" title="localtime"> 10<link rel="next" href="strftime.html#strftime" title="strftime"> 11<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> 12<meta http-equiv="Content-Style-Type" content="text/css"> 13<style type="text/css"><!-- 14 pre.display { font-family:inherit } 15 pre.format { font-family:inherit } 16 pre.smalldisplay { font-family:inherit; font-size:smaller } 17 pre.smallformat { font-family:inherit; font-size:smaller } 18 pre.smallexample { font-size:smaller } 19 pre.smalllisp { font-size:smaller } 20 span.sc { font-variant:small-caps } 21 span.roman { font-family:serif; font-weight:normal; } 22 span.sansserif { font-family:sans-serif; font-weight:normal; } 23--></style> 24<link rel="stylesheet" type="text/css" href="../cs.css"> 25</head> 26<body> 27<div class="node"> 28<a name="mktime"></a> 29<p> 30Next: <a rel="next" accesskey="n" href="strftime.html#strftime">strftime</a>, 31Previous: <a rel="previous" accesskey="p" href="localtime.html#localtime">localtime</a>, 32Up: <a rel="up" accesskey="u" href="Timefns.html#Timefns">Timefns</a> 33<hr> 34</div> 35 36<h3 class="section">8.7 <code>mktime</code>—convert time to arithmetic representation</h3> 37 38<p><a name="index-mktime-438"></a><strong>Synopsis</strong> 39<pre class="example"> #include <time.h> 40 time_t mktime(struct tm *<var>timp</var>); 41 42</pre> 43 <p><strong>Description</strong><br> 44<code>mktime</code> assumes the time at <var>timp</var> is a local time, and converts 45its representation from the traditional representation defined by 46<code>struct tm</code> into a representation suitable for arithmetic. 47 48 <p><code>localtime</code> is the inverse of <code>mktime</code>. 49 50 <p><br> 51<strong>Returns</strong><br> 52If the contents of the structure at <var>timp</var> do not form a valid 53calendar time representation, the result is <code>-1</code>. Otherwise, the 54result is the time, converted to a <code>time_t</code> value. 55 56 <p><br> 57<strong>Portability</strong><br> 58ANSI C requires <code>mktime</code>. 59 60 <p><code>mktime</code> requires no supporting OS subroutines. 61 62 <p><br> 63 64 </body></html> 65 66