Zero-length static array spec

[Iain Buclaw via Digitalmars-d]

On 6 February 2015 at 23:42, David Nadlinger via Digitalmars-d
<digitalmars-d at puremagic.com> wrote:
> On Friday, 6 February 2015 at 23:37:30 UTC, Iain Buclaw wrote:
>>
>> Simple, you implement it by allocating no memory. :)
>
>
> Let me put it a different way. Imagine you have this in your program:
>
> ---
> void foo() {
>   int[0] a0;
>   int[0] a1;
>   ...
>   int[0] a99;
>
>   // Do something with them.
> }
> ---
>
> How do you choose the addresses for a0 through a99 so that they are
> distinct, but you don't end up allocating 100 bytes of stack memory?
>
> David

There are no addresses for them, you can't do *anything* with them at runtime.

Some cod scenarios:
1. Comparisons of == fold into 'false'  (unless comparing to self)
2. Comparisons of != fold into 'true'  (unless comparing to self)
3. Conversion to dynamic arrays is { .length=0, .ptr=&arr0 }

You cannot assign memory/address to them directly, but you can assign
it indirectly.  This 'indirect assignment' can only really work if it
were the last member of a struct.  Example usage -
http://goo.gl/uAbxKN - something like a pointer-based dynamic array.

Labels probably do best describe their exact behaviour.

Iain.