title: Error on syntax for generating coverage data from multiple files using lcov in Windows
body: <p>I would like some help... I'm having trouble coming up with the syntax to generate coverage data from multiple files using lcov in Windows.</p>
  
  <p>I have gcov, lcov and genhtml installed on cygwin (I'm running this under Windows).  All of those files are inside cygwin/bin directory.  The coverage data I flush through I believe are perl scripts created from <a href="http://code.google.com/p/js-test-driver/wiki/CodeCoverage" rel="nofollow noreferrer">JsTestCoverage</a> and has the following format:</p>
  
  <pre><code>SF:C:/test/jquery.js
  DA:22,1
  DA:23,1
  ...
  end_of_record
  SF:C:/test/testFile.js
  DA:3,1
  DA:6,1
  ...
  end_of_record
  //rinse and repeat till no more files
  </code></pre>
  
  <p>Note I have NOT used genhtml on the coverage data yet.</p>
  
  <p>I then tried something like:</p>
  
  <pre><code>perl genhtml /../home/administrator/coverage1.dat /../home/administrator/coverage2.dat
  </code></pre>
  
  <p>But got an error saying:</p>
  
  <pre><code>genhtml: Can't use an undefined value as a HASH reference at genhtml line 1506.
  </code></pre>
  
  <p>I'm not sure whether I've got the process wrong either, being not from linux background at all.</p>
  
  <p>Thanks in advance.</p>