title: MinGW creating dll.a files ? What type of library files are those?
body: <p>I am fairly familiar with Windows and Linux libraries compilation but as for today when I have seen <code>MinGW</code> on my Windows machine threw out <code>dll.a</code> and <code>.a</code>  files after OpenCV compilation I have started to seriously start thinking. </p>
  
  <p>These are my <code>\lib</code> output from OpenCV compilation : </p>
  
  <pre><code>2012-12-21  23:35         1 338 420 libopencv_core243.dll.a
  2012-12-21  23:33           224 994 libopencv_core_pch_dephelp.a
  2012-12-21  23:38           830 820 libopencv_features2d243.dll.a
  </code></pre>
  
  <p>And my <code>\bin</code> output : </p>
  
  <pre><code>2012-12-21  23:40           356 178 libopencv_perf_core.dll.a
  2012-12-21  23:45           362 702 libopencv_perf_features2d.dll.a
  2012-12-21  23:35         4 086 052 libopencv_core243.dll
  2012-12-21  23:38         2 102 896 libopencv_features2d243.dll
  </code></pre>
  
  <p>(I obviously have more binaries but there is no sense in listing it here) </p>
  
  <p>Can someone tell me if these are normal static libraries that I can link against ? and how should I link against them ?</p>