> Yeah, but it’s a shame that those compilers define __GNUC__ without > supporting 100% of the GNU C extensions. With this approach, you would > also need to add !defined for Clang, PGI, and probably others.
Having worked on the other side for a while -- for a vendor whose compiler supported many but not all of GCC's extensions -- I claim that the problem is with the many examples of code out there that blindly test for __GNUC__ instead of testing for individual extensions. From the other vendor's point of view, it's nearly useless to support any of the GCC extensions if you don't also define __GNUC__, because most code out there will simply test for that macro. By defining the macro even if you don't support, for example, nested functions, you can still compile 99% of the code that uses the extensions. -cary
