Apple's GCC 42 enhancements (was Re: [CFT] Experimental gcc update).

[David Chisnall]

On 2 Jan 2014, at 20:22, Pedro Giffuni <pfg at FreeBSD.org> wrote:

> The behaviour is consistent with llvm-gcc though, as explained here:
> 
> https://bugs.launchpad.net/ubuntu/+source/llvm-gcc-4.2/+bug/483679
> 
> " looking at the LLVM/Clang documentation (http://clang.llvm.org/doxygen/InitPreprocessor_8cpp-source.html) shows that __block is not actually a keyword, but a macro that is defined to be __attribute__((__blocks__(byref)))."
> 
> Not sure what to do about it, I had added a #define for it in Block.h since you have to link with -lBlocksRuntime anyways, but not everything includes Block.h (surely not the libdispatch tests).

Probably the best solution is to put this in cdefs.h:

#if defined(__BLOCKS__) && !defined(__block)
#	define __block __attribute__((__blocks__(byref)))
#endif

(With the indentation changed to make it harder to read, as per style(9)).  I believe __BLOCKS__ is supported by clang, although testing for it is discouraged in favour of the __has_{feature,extension} mechanism.  

David