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Subject: RE: [RFC] vsprintf: compile error on %09pK
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From:   Jaewon Kim <jaewon31.kim@samsung.com>
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        Jaewon Kim <jaewon31.kim@gmail.com>
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Date:   Tue, 04 Apr 2023 19:16:06 +0900
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>[..]
>> 
>> Okay, then we can't use %09pK. I've just wondered because %9pK works.
>
>This is not per printk / kernel, Wformat warnings come from the
>compiler.
>
>Per C11 (7.21.6 6):
> 0  For d, i, o, u, x, X, a, A, e, E, f, F, g, and G conversions, leading zeros
>    (following any indication of sign or base) are used to pad to the field width
>    rather than performing space padding
>    ...
>    For other conversions, the behavior is undefined.
>
>So using 0 for p should trigger an undefined behavior as far as the
>standard C concerned. Unless I'm missing something.

Thank your for the information about the leading 0 case. By the way do you know
if there is policy for none 0 digit like %9pK?

Jaewon Kim