Re: [PATCH V2] sparse: Allow override of sizeof(bool) warning

[H. Peter Anvin]

Keep in mind, too, that for the kernel we don't care about the full C standard but a subset.  We rely on extrastandard behavior all over the place.  For all ABIs supported by the kernel, sizeof(_Book) == 1 and so everything is sane.


On February 27, 2014 12:25:29 AM PST, Borislav Petkov <bp@xxxxxxxxx> wrote:
>On Wed, Feb 26, 2014 at 07:42:37PM -0800, H. Peter Anvin wrote:
>> sizeof(_Bool), like for many other types, is ABI-dependent, but that
>> doesn't mean it is illegitimate.
>>
>> I don't think C99 says that it is invalid (which means C99 doesn't
>> permit is to be a packed bitmap.)
>
>Ok, but what can be said about the __pcpu_size_call() use case where we
>do sizeof(bool)? We have there accessors for sizes 1,2,4 and 8. Can we
>simply assume that the ABI will give us a size of bool which is one of
>those?
>
>What if sizeof(bool) is 3?
>
>Or, are we saying that sizeof(bool) will always be of some natural,
>native size like byte, short, int or long so we're good there?
>
>Thanks.

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