[PATCH] D12747: Implement [depr.c.headers]

[Richard Smith via cfe-commits]

On Thu, Oct 8, 2015 at 11:50 AM, Marshall Clow <mclow.lists at gmail.com>
wrote:

> On Tue, Oct 6, 2015 at 3:57 PM, Richard Smith <richard at metafoo.co.uk>
> wrote:
>
>> <stddef.h>. This one is tricky:
>>
>> 1) There's an (undocumented) interface between the C standard library and
>> this header, where the macros __need_ptrdiff_t, __need_size_t,
>> __need_wchar_t, __need_NULL, __need_wint_t request just a piece of this
>> header rather than the whole thing. If we see any of those, just go
>> straight to the underlying header.
>>
>
> Ok, but in that case we don't get nullptr.  I suspect that's OK.
>
>
>> 2) We probably don't want <stddef.h> to include <cstddef> (for
>> consistency with other headers)
>>
>
> No, we do not! :-)
>
>
>> , but <stddef.h> must provide a ::nullptr_t (which we don't want
>> <cstddef> to provide). So neither header includes the other. Instead, both
>> include <__nullptr> for std::nullptr_t, and we duplicate the definition of
>> max_align_t between them, in the case where the compiler's <stddef.h>
>> doesn't provide it.
>>
>> If you prefer, I could make <stddef.h> include <cstddef> to avoid the
>> duplication of the max_align_t logic.
>>
>
> No; this is a minor annoyance, and layer jumping (<stdXXX.h> including
> <cstdXXX>) is a major annoyance - and I'm pretty sure that that would come
> back to bite us in the future.
>
> Looks ok to me.
>

Thanks, everything up to and including patch 09 is now committed.
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