[webkit-dev] Unsigned to avoid negative values

Jean-Yves Avenard jean-yves.avenard at apple.com
Tue Jan 24 02:25:12 PST 2023


I could have sworn reading a few years ago a white paper discussing signed vs unsigned discussed with Blink coding style showing that using unsigned had a performance impact. 

Of course, now I can’t find reference to it. 

But I clearly recall recommendations like you mentioned. 


Sent from my iPhone

> On 24 Jan 2023, at 9:00 pm, Myles Maxfield via webkit-dev <webkit-dev at lists.webkit.org> wrote:
> 
> Hello!
> 
> I recently learned that the C++ core guidelines recommend against using unsigned to avoid negative values. Section 4.4 on page 73 of The C++ Programming Language says unsigned types should be used for bitfields and not in an attempt to ensure values are positive. Some talks by people on the C++ standards committee (e.g., Herb Sutter) recommend against using unsigned types simply because the value is expected to by positive.
> 
> Should we be avoiding unsigneds for these purposes? WebKit uses unsigneds all over the place, and I’m assuming a fair many of them are there to indicate that negative values are avoided. The C++ recommendation goes against my intuition that the type is there for clarity, to indicate expectations about the meaning and behavior of its value. But if it’s standard practice to just use int instead, perhaps we should update the style guide?
> 
> What do you think?
> 
> —Myles
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