title: comparison between signed and unsigned integer expressions warning while make install?
body: <p>I am running my below code which checks whether <code>data_timestamp</code> is more than two weeks old or not. If it is more than two weeks old, then print <code>hello</code> otherwise prints <code>world</code>. </p>
  
  <pre><code>#include &lt;boost/chrono/chrono.hpp&gt;
  #include &lt;iostream&gt;
  
  int main()
  {
      uint64_t data_timestamp = 1406066507000;
  
      const boost::chrono::system_clock::time_point now = boost::chrono::system_clock::now();
      boost::chrono::hours twoWeeks = boost::chrono::hours(24 * 14);
      boost::chrono::system_clock::time_point lastTwoWeeks = now - twoWeeks;
  
      boost::int_least64_t millis = boost::chrono::duration_cast&lt;boost::chrono::milliseconds&gt;(lastTwoWeeks.time_since_epoch()).count();
  
      std::cout &lt;&lt; "Time stamp in milliseconds since UNIX epoch start: "&lt;&lt; millis &lt;&lt; std::endl;
  
      if (data_timestamp &lt; millis) {
          std::cout &lt;&lt; "Hello";
      } else {
          std::cout &lt;&lt; "World";
      }
  
      return 0;
  }
  </code></pre>
  
  <p>And my above code is working fine but there is one warning on this if statement comparison -</p>
  
  <pre><code>if (data_timestamp &lt; millis) {
  </code></pre>
  
  <p>And the warning I am seeing is -    </p>
  
  <pre><code>warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  </code></pre>
  
  <p>How do I remove this warning? I would like to keep <code>data_timestamp</code> as <code>uint64_t</code> since in the actual code it is being used like that in other places as well.</p>