title: How can I ignore some directories in Doxygen?
body: <p>I tried Doxygen to see how it documents a code.<br />
  The big problem I encountered is that it scans all the subdirectories, however I need to <strong>avoid some of them because not needed</strong> in the final documentation (they are also inappropriate because not direct parts of my work).<br />
  I think it's possible from the Expert tab of the Doxygen's wizard, but I'm a newbie and I don't understand how to set them.<br />
  Finally, what happens to the references to the directories excluded (i.e. references to functions, variables, etc...)?</p>