title: Cannot auto-complete c++ in vs code
body: <p>Hey I recently started using vs code and am having a really weird issue. where my code won't auto complete. I have installed the c/c++ extension and have the "c_cpp_properties.json" file containning the following</p>
  
  <pre><code>{
      "configurations": [
          {
              "name": "Mac",
              "includePath": ["/usr/include"]
          },
          {
              "name": "Linux",
              "includePath": ["/usr/include"]
          },
          {
              "name": "Win32",
              "includePath": ["c:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/include"]
          }
      ]
  }
  </code></pre>
  
  <p>Before you ask I have copied proper include path to "/usr/include" I just did a really simple test I wrote 1 line </p>
  
  <p>"VkInstance instance;"
  It compiled and ran fine but whenever I start to type VkInstance It never comes up as auto complete. Moreover weirdly some stuff auto completes fine and other stuff doesn't for example "vkCreateInstance" shows up as i'm typing it. Perhaps I'm missing something or doing something wrong would like some feedback </p>
  
  <p>Thanks!</p>
  
  <pre><code>#include &lt;vulkan/vulkan.h&gt;
  
  int main()
  {
      VkInstance instance;
  
      return 0;
  }
  </code></pre>