[bug-gnulib] Re: [bug-grep] Re: length of dec. representation of a number

[Paul Jarc]

Stepan Kasal <address@hidden> wrote:
>> #define TYPE_MAXIMUM(t) \
>>   ((t) (! TYPE_SIGNED (t) \
>>      ? (t) -1 \
>>      : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
>
> For unsigned types on signed magnitude hosts, ((t) -1) is wrong.

No, the standard explicitly says it's correct, for any representation.
Conversion of an out-of-range value to an unsigned type works by
reducing the value module <type>_MAX+1, so (type)-1==<type>_MAX.


paul