title: Instance abstract class that is implemented elsewhere?
body: <p>I'm making a plugin DLL for 3dsmax. The SDK includes one particular class full of pure virtual functions that the documentation says are implemented by max itself. I know these functions are implemented, because class instances are sometimes passed to my plugin through functions in my plugin that max calls from its core api. </p>
  
  <p>However, if I try to instance that class within my code, I cannot since all of its functions are pure virtual in the 3dsmax SDK. </p>
  
  <p>Is there any way to tell the c++ compiler that even though the functions it sees are pure virtual, they are implemented somewhere else (in another .dll visible to the program)? The declarations of the functions in question are not in any of the 3dsmax .libs or includes...so it's 100% certain that they're outside the scope of my code....but they <em>are</em> out there.</p>
  
  <p>I'm new to c++ so I apologize if this is a dumb question.</p>