title: Doxygen: multiple \mainpage blocks in a C++ project
body: <p>I wasn't able to determine what the behavior of doxygen is regarding the <code>\mainpage</code> section, in two cases:</p>
  
  <ol>
  <li>If you specify no <code>\mainpage</code> section, does it use any other page instead and if so how is this picked?</li>
  <li>What if two files both specify a <code>\mainpage</code> section?</li>
  </ol>