title: Why do some functions/variables have the character "_" in front of them , in C++ ?
body: <p>I've seen quite a lot lately, in games or other applications that class data members, or methods or other stuff have "_" in front of the name.
  For example taken fro DXUT.cpp (Directx) <code>_Acquires_lock_(g_cs)</code> or <code>_Releases_lock_(g_cs)</code> or <code>_tmain</code> . There are numerous examples like this in game programming like there (Taken from GameFromScratch Tutorial) </p>
  
  <pre><code>  static GameState _gameState;
    static sf::RenderWindow _mainWindow;
  </code></pre>
  
  <p>These are just some data members of some type.</p>
  
  <p>Is there any reason behind the _ char? Is if specifically for something?</p>