float init 0 request

[Richard (Rikki) Andrew Cattermole]

On 14/08/2026 8:19 PM, ABrightLight wrote:
> On Friday, 14 August 2026 at 06:38:02 UTC, Walter Bright wrote:
>> Floats are default initialized to NaN so people will be coerced to 
>> explicitly code what they want the initialized value to be.
>>
>> I've seen enough code where the programmer forgot to initialize a 
>> float, it was defaulted to 0, and the wrong result was not detected.
>>
>> ```d
>> float f;     // code reviewer: did the programmer intend it to be 0?
>> float g = 0; // code reviewer: yes, the programmer likely meant to 
>> initialize it to 0
>> ```
>>
>> It's similar to pointers being default initialized to null. Trying to 
>> use a null pointer will result in a seg fault.
>>
>> Most people decry this, but it's actually a great feature. If there's 
>> a bug in the code, it's better to find it sooner rather than after you 
>> ship.
> 
> Hi Walter, I really appreciate the response, however I think that all 
> the points I wrote were unaddressed (I mentioned the comparison with 
> null pointers and why it is my opinion that it is a false equivalence as 
> well).

Unfortunately this is a good example of Walter leaving out the analysis, 
and skipping to the conclusion. I spend a good chunk of my time figuring 
out what the analysis was lol.

NaN's come in two flavors, signaling and non-signaling.

Originally D default initialized floats to signal, but that was changed 
as it was producing an inconsistency that was a problem (I wasn't 
involved with this).

If you try to do math on a signaling NaN it will throw a hardware 
exception, just like doing a null dereference does.

A non-signaling NaN is good, because you can at least detect when 
something has gone wrong, just not the source.

Silent corruption is always worse than detectable corruption.

> Nevertheless, the topic is relatively low importance to me and I'm okay 
> with just using a linter to remind myself to explicitly initialize the 
> floats. I just figured the change would be an easy QOL improvement for 
> most users.

https://forum.dlang.org/thread/tcfqveygmebplsgmexgr@forum.dlang.org