C++: How do I know what exception in catch with ellipsis

Question

On Linux environment using g++ 4.9.2 compiler, in a C++ code, I have try .. catch block, as below:

try {
// some code
}
catch (ExceptionCode &ex) 
{
  // ExceptionCode type of exception
}
catch (...) {
  // how do I know which exception code so that I may check who did throw
}

Clue?