title: Export function to DLL without class
body: <p>Is there a way to export only a function to DLL cos in tutorials they always export classes with something like: </p>
  
  <pre><code> static __declspec(dllexport) double Add(double a, double b);
  </code></pre>
  
  <p>Inside a class the statement above does not cause any problem, but without a class it gives: </p>
  
  <pre><code> dllexport/dllimport requires external linkage
  </code></pre>