Guido van Rossum <guido@CNRI.Reston.VA.US>:

Rant aside, what compiler is going to support different datatype sizes for stuff declared extern "C" than for native C++ types? Get real.

My understanding is that the issue usually isn't datatype sizes, it's the calling convention. The ABI for C++ functions may be different than for C functions. extern "C" gives that the C++ compiler that clue. Clueless compilers require extension keywords, such as __cdecl, for similar effects. Greg Couch gregc@cgl.ucsf.edu (c++-sig digest reader)