Wrong. Apple's C is C99 (as implemented by both gcc and clang). If you wish to take advantage of something like Grand Central Dispatch, they recommend that you

Wrong. Apple's C is C99 (as implemented by both gcc and clang). If you wish to take advantage of something like Grand Central Dispatch, they recommend that you do so with their completely optional syntax for blocks (which, aside from being closures AFAIK, are essentially anonymous functions in situ instead of defining a function externally). You can still use GCD without the new block syntax by using function pointers, leaving you with bog standard C99. Frankly, gcc implements a lot more non-standard stuff on its own than Apple's blocks have introduced.