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POC++: how to get the actual time with time and localtime?
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  1. POC++: how to get the actual time with time and localtime?
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    copied!<p>I'm looking for a way to save the time in a HH::MM::SS fashion in C++. I saw here that they are many solutions and after a little research I opted for <code>time</code> and <code>localtime</code>. However, it seems like the <code>localtime</code> function is a little tricky, since it <a href="http://rabbit.eng.miami.edu/info/functions/time.html#localtime">says</a>: </p> <blockquote> <p>All calls to localtime and gmtime use the same static structure, so each call overwrites the results of the previous call.</p> </blockquote> <p>The problem that this causes is shown in the next snippet of code:</p> <pre><code>#include &lt;ctime&gt; #include &lt;iostream&gt; using namespace std; int main() { time_t t1 = time(0); // get time now struct tm * now = localtime( &amp; t1 ); std::cout &lt;&lt; t1 &lt;&lt; std::endl; sleep(2); time_t t2 = time(0); // get time now struct tm * now2 = localtime( &amp; t2 ); std::cout &lt;&lt; t2 &lt;&lt; std::endl; cout &lt;&lt; (now-&gt;tm_year + 1900) &lt;&lt; '-' &lt;&lt; (now-&gt;tm_mon + 1) &lt;&lt; '-' &lt;&lt; now-&gt;tm_mday &lt;&lt; ", " &lt;&lt; now-&gt;tm_hour &lt;&lt; ":" &lt;&lt; now-&gt;tm_min &lt;&lt; ":" &lt;&lt; now-&gt;tm_sec &lt;&lt; endl; cout &lt;&lt; (now2-&gt;tm_year + 1900) &lt;&lt; '-' &lt;&lt; (now2-&gt;tm_mon + 1) &lt;&lt; '-' &lt;&lt; now2-&gt;tm_mday &lt;&lt; ", " &lt;&lt; now2-&gt;tm_hour &lt;&lt; ":" &lt;&lt; now2-&gt;tm_min &lt;&lt; ":" &lt;&lt; now2-&gt;tm_sec &lt;&lt; endl; } </code></pre> <p>A typical output for this is: </p> <pre><code>1320655946 1320655948 2011-11-7, 9:52:28 2011-11-7, 9:52:28 </code></pre> <p>So as you can see, the <code>time_t</code> timestamps are correct, but the localtime messes everything up. </p> <p>My question is: how do I convert a timestamp ot type <code>time_t</code> into a human-readable time?</p>
 

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