Re: [PATCH v2 4/5] parse-options: introduce `OPTION_UNSIGNED`

From: phillip.wood123@gmail.com <phillip.wood123@gmail.com>
Date: Apr 16, 2025, 13:31 UTC
Message-ID: <7c684f2b-ca56-4e8b-b141-0c2f6b64a44a@gmail.com>
In-Reply-To: <Z_-GKX8uFSNib5rW@pks.im>

On 16/04/2025 11:27, Patrick Steinhardt wrote:

Show 12 quoted lines

> On Tue, Apr 15, 2025 at 04:52:02PM +0100, Phillip Wood wrote:
> 
> Wait, does it? Why would `strtoul()` or any of its variants ever accept
> a string prefixed with a "-"?
> 
>      If the minus sign was part of the input sequence, the numeric value
>      calculated from the sequence of digits is negated as if by unary
>      minus in the result type, which applies unsigned integer wraparound
>      rules.
> 
> Oh dear... all these integer conversion functions are really a gift that
> keeps on giving. Gross.

Yes it's horrible behavior for a function that parses an unsigned integer. We should perhaps think about adding 64 bit versions of strtoui_i() and strtoul_ui() so we have a safer option for parsing large integers but I don't think we need to do that as part of this series.

I'll try and take a look at V3 tomorrow

Phillip

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>> This patch also needs the fix from patch 2 to detect overflows for
>> uintmax_t.
> 
> Yup, will add.
> 
> Patrick