On 2/23/23 06:20, Paavo Helde wrote:
> 23.02.2023 12:34 Muttley@dastardlyhq.com kirjutas:
....
>> Undefined would just be returning
>> rubbish. I can't even figure out HOW it would crash since all its
>> doing is
>>
>> return (c >= '0' && c <= '9')
>
> Nope, because it's not known at the compile time which characters
> should be considered digits. It might do something like

No, isdigit() and isxdigit() are special cases. They are not
locale-dependent. Regardless of locale, which characters qualify is
defined by cross-referencing section 5.2.1.