Re: [PATCH 3/3] reftable tests: avoid "int" overflow, use "uint64_t"

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 12, 2022, 19:02 UTC
Message-ID: <xmqqh7a8vkuq.fsf@gitster.g>
In-Reply-To: <e8e2c37d-39f1-0ae4-7894-07e85628a757@kdbg.org>

Johannes Sixt <j6t@kdbg.org> writes:

Show 20 quoted lines

> Am 11.01.22 um 21:18 schrieb Taylor Blau:
>> On Tue, Jan 11, 2022 at 09:08:46PM +0100, Johannes Sixt wrote:
>>> Am 11.01.22 um 20:41 schrieb Taylor Blau:
>>>> On Tue, Jan 11, 2022 at 08:31:47PM +0100, Han-Wen Nienhuys wrote:
>>>>> On Tue, Jan 11, 2022 at 8:28 PM Taylor Blau <me@ttaylorr.com> wrote:
>>>>>> In any case, you're only setting the lower half of `min` high. Maybe:
>>>>>>
>>>>>>     uint64_t min = ~0ul;
>>>>>
>>>>> yeah, that works.
>>>>
>>>> I'm pretty sure this is OK on 32-bit systems, too, but confirmation from
>>>> somebody more confident than I in this area would be welcome :).
>>>
>>> It does not work on Windows: unsigned long is 32 bits wide. You have to
>>> make it
>>>
>>>    uint64_t min = ~(uint64_t)0;
>> 
>> Perfect; this is exactly what I was looking for. Thanks!

That sounds perfect.

> Actually, on second thought, UINT64_MAX would be even better.

I wouldn't introduce use of UINT64_MAX, which "git grep" does not produce any hits for.

Unless it is very early in a development cycle, that is, in which case we have enough time to help platforms that are not quite POSIX.