Re: compiler standards (and/or min gcc version) supported with installedheaders ?

[Carlos O'Donell <carlos at systemhalted dot org>]

On 01/03/2013 11:29 AM, Andreas Jaeger wrote:
> On 01/03/2013 05:25 PM, Carlos O'Donell wrote:
>> On 01/03/2013 10:58 AM, Joseph S. Myers wrote:
>>> On Thu, 3 Jan 2013, Andreas Jaeger wrote:
>>>
>>>>> Thus for example we could get rid of the GCC 2.91 check for __builtin_memset
>>>>> in sysdeps/unix/sysv/linux/bits/sched.h and clean that up.
>>>>
>>>> That raises a separate question - shall we assume that non-GCC compilers have
>>>> __builtin_memset as well?
>>>>
>>>> Otherwise the cleanup would be to change the got to use
>>>> GLIBC_HAVE_BUILTIN_MEMSET - and define that for GCC.
>>>
>>> Defining __GLIBC_HAVE_BUILTIN_MEMSET seems logically right.  (You can't
>>> just define __builtin_memset to memset because string.h may not be
>>> included.  So you don't really clean much up in this case because you
>>> still have both cases in the code - and given that there's still a GCC
>>> conditional somewhere, there doesn't really seem to be much advantage in
>>> the test being __GNUC__ instead of __GNUC_PREREQ (2, 91).)
>>
>> Good question about alternative compilers.
>>
>> I have no objection to the cleanup that makes this a feature.
>>
>> I guess the next step then is to enumerate supported compilers
>> and then decide if the feature is to be assumed or not, and then
>> follow that up with further cleanup.
> 
> right now, I would only mention GCC as supported compiler - and add
> others only if somebody steps up that is using that compiler and will
> take care of the support on glibc. nevertheless, I would be
> conservate and handle GCC extensions as extensions - something we
> need to test for before using it.

Well in that case then the GLIBC_HAVE_BUILTIN_MEMSET is *assumed*
since we support only GCC, and versions 2.91 or newer always
have that builtin, so the code can be cleaned up?

Did I understand that correctly?

Cheers,
Carlos.