Thread: Testing if a macro is defined to a value?

Say I have something lke

Code:

#define FOO BAR

#if FOO == BAR
  doX();
#else
  doY();
#endif

This causes doX(); to be executed. But the intent is to have doY(); be run. I'm guessing this is because BAR is undefined and therefore blank, so blank equals blank. Is there some way to compare the symbol FOO was set to instead of its value, BAR?