Not initialized out argument error

[Iain Buclaw via Digitalmars-d]

On 17 June 2014 10:24, Walter Bright via Digitalmars-d
<digitalmars-d at puremagic.com> wrote:
> On 6/17/2014 1:55 AM, bearophile wrote:
>>
>> Walter Bright:
>>
>>> But it is not uninitialized. All out parameters are default initialized
>>> to
>>> their .init value.<
>>> I don't agree with this opinion, as they *are* initialized.<
>>
>>
>> The documentation of Microsoft SAL2, several discussions, and some other
>> things
>> I've read tell me that if you want your compiler to catch some of your
>> bugs
>> statically (and optimize well) it needs to be strict.
>
>
> Microsoft SAL2 is not about D, and D's 'out' has nothing to do with
> strictness. Frankly, I think D's parameter classes and array slices are far
> simpler and more effective than SAL2.
>
>
>
>> How much often do I need to write a function like foo?
>> I think it's uncommon.
>
>
> I suspect that is a guess.
>
>
>
>> If this little breaking change is introduced in D, I am then forced to
>> write foo
>> like this:
>>
>> void foo2(out int x) { x = 0; }
>>
>> Is this a price small enough to pay for that increase in strictness?
>
>
> I see it as annoying and nothing to do with 'strictness'. D default
> initializes all variables that don't have an explicit initializer. This is
> normal for D, and is a nice convenience. There's no reason that 'out' should
> behave differently.
>
> It's also a correctness feature - the default initializer is NOT always 0,
> and if you're writing generic code you'd be making a mistake to use 0. You'd
> have to initialize it to 'typeof(x).init', which is a good way of punishing
> users :-)
>

Floats are a better example of punishing users at runtime.

void foo3(out float x) { }