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

[Pedro Giffuni]

On 02.01.2014 16:48, David Chisnall wrote:
> 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.

Thank you for the hint. Is there some way to have this happen
only for our GCC-4.2.1 but not for clang or newer gcc?

I am getting ready to commit the blocks support [1] but we can
leave the macro magic for later, while there is some consensus
on the dark arts involved ;).

Pedro.

[1] I ran buildworld and rebuilt boost and some ports with the modified
compiler ... so far, so good. I don't think an exp-run is necessary 
since the blocks stuff is not yet being used for any port.