How can I determine which C++ compiler is used if I only can alter the C++ code and inspect console output?

Suppose there's a system like codepad.org - a black box t开发者_开发问答hat can accept C++ code, compile it, run it and present the console output. How could I determine what C++ compiler such system uses?

You could have an ifdef fest to detect what the compiler is, using all the information compiled in this page.