title: Using a static std::map<int,MyClass*> inside MyClass causes unresolve external symbol
body: <p>I want to keep track of the instance of <code>MyClass</code>, so I have add a private static variable <code>std::map&lt;int,MyClass*&gt;</code> inside MyClass. The problem now is it causes unresolved external symbol, which I don't know how to debug. How can I resolve this?</p>
  
  <p>Note: I'm a seasoned Java programmer and novice C++ programmer, and also I'll be using this as a <code>JNI</code> <code>dll</code>, that is why I need to keep track the instances of <code>MyClass</code>.</p>