[cfe-dev] gcc quirk not implemented

[Chris Lattner]

On Oct 21, 2008, at 9:00 AM, Eli Friedman wrote:

> On Tue, Oct 21, 2008 at 6:36 AM, Roman Divacky  
> <rdivacky at freebsd.org> wrote:
>> hi
>>
>> gcc accepts this code:
>>
>> int
>> __xuname(int namesize, void *namebuf)
>> {
>>       struct xutsname {
>>               char    sysname[namesize];      /* Name of this OS. */
>>       } *name;
>> }
>>
>> which clang refuses with:
>>
>> const.c:5:25: error: arrays with static storage duration must have  
>> constant integer length
>>               char    sysname[namesize];      /* Name of this OS. */
>>                                       ^~~~~~~
>>
>> note that this violates C99 but obviously it's used (for example in  
>> freebsd libc code)
>> so I believe it should get implemented.
>
> Thanks for the report; please file in Bugzilla so it doesn't get lost.
> Looks like a serious pain to implement (structs with multiple
> variable-sized members, anyone?), but I guess that's gcc compat.

Yeah, GCC allows stuff after VLAs as well in structs (which is  
exposing an Ada feature through to C).  I personally have no interest  
in implementing this sort of thing in Clang, but if someone else  
wanted to work on it, I wouldn't object :)

-Chris