title: where is PROJECT_DIRECTORY in YCM-Generator
body: <p>I Installed YouCompleteMe on vim.</p>
  
  <p>For python it works, but not for C/C++.</p>
  
  <p>I tried to install YCM-Generator, but I don't understand where <code>PROJECT_DIRECTORY</code> is in my Linux environment.</p>
  
  <pre><code>Run ./config_gen.py PROJECT_DIRECTORY, where PROJECT_DIRECTORY is the root directory of your project's build system (i.e. the one containing the root Makefile, etc.)
  </code></pre>