title: Why can't I use <experimental/filesystem> with g++ 4.9.2?
body: <p>I am trying to use <a href="http://en.cppreference.com/w/cpp/experimental/fs/path" rel="noreferrer">filesystem</a>. I have <code>-std=c++11 -std=c++1y</code> in my <code>CMakeLists.txt</code>. GCC version is <code>4.9.2</code>. However, I have got an error:</p>
  
  <pre><code>/home/loom/MyProject/src/main.cpp:5:35: fatal error: experimental/filesystem: No such file or directory
   #include &lt;experimental/filesystem&gt;
                                     ^
  compilation terminated.
  </code></pre>
  
  <p>What is the right way to use <code>std::experimental::filesystem</code>?</p>