Originally Posted by robatino They're allowed in C99 but not C90. Annoyingly, GCC and MSVC both allow them, so often you don't even realize you've done it.
Originally Posted by brewbuck Annoyingly, GCC and MSVC both allow them, so often you don't even realize you've done it. GCC will complain when given -ansi, so it's easy enough to just compile once with "-W -Wall -ansi -pedantic" when the code is done to purge these things.