title: Visual Studio 2015 include paths
body: <p>I seem to fail to understand how VS 2015 handles include paths. I have put the folders I need VS to scan for included files in the following places in the "Properties" pane of my project :</p>
  
  <p>Configuration Properties > VC++ Directories > Include Directories</p>
  
  <p>Configuration Properties > C/C++ > General > Additional Include Directories</p>
  
  <p>But when I ask for a build I get :</p>
  
  <pre><code>fatal error C1083: Cannot open include file: 'xyz.h': No such file or directory
  </code></pre>
  
  <p>The spelling has been double-checked. I tried it with a dummy project which I can send, same behavior. I have tried with both slash and anti-slash. Actually some folders are subfolders of the project folders and do not require any slash or anti-slash in their path description (simply the folder name). Those also fail to be scanned and their contents remains unfound by the compiler.</p>
  
  <p>I also tried specifying the path manually in the include directive, this works.</p>
  
  <p>I also opened a project where everything is working and I added a new include directive to a newly created file in a folder which I added to the include path. This project now fails to compile.</p>
  
  <p>Better yet, still using that old project that was compiling fine, if I remove one (or even all) folders from the Additional Include Directories filed in C/C++ > General <strong>it still compiles !</strong> So this must be the wrong place to specify include dirs !</p>
  
  <p>What do I not know here ? Thanks in advance !</p>