RE: [RFC] vsprintf: compile error on %09pK

From: Jaewon Kim
Date: Tue Apr 04 2023 - 06:16:21 EST


>[..]
>>
>> 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