Wouldn't this be better with bitfields?

[Mike Parker]

On Tuesday, 9 July 2024 at 10:57:02 UTC, claptrap wrote:

>
> You have completely missed the point. Struct layout doesn't 
> change, it's fixed, it doesn't depend on what C compiler is 
> attached.

The layout is fixed, but alignment and padding are implementation 
specific.

>
> It's not C-compatibility, but letting the under specification 
> of C bitfields basically infect D. Its the tail wagging the 
> dog. Or leaky implementation. If I have a D program that links 
> a dll or static lib also written in D, they could have 
> incompatible bitfield layouts.
>
> You could fix this by specifying the layout for D bitfields, 
> and using extern(C) when compatibility with the relevant C 
> compiler is required. D already does that for classes and 
> functions...

`extern(C)` does not affect the layout of anything, as far as I 
know. It only impacts name mangling and calling convention. Using 
it to change layout would be a new feature.

When I worked on Derelict and BindBC, I would have loved to have 
had bitfields in D. And I would have expected them to line up 
with the associated C compiler out of the box, because that's 
what already happens with structs.