On Wednesday, 16 July 2025 at 13:29:01 UTC, z wrote:
I also see this in the language documentation :
```
A void array cannot be indexed.
```
But i can slice it just fine in DMD 2.111...
You can _slice_ it, meaning, getting a subarray out of it.
However, _indexing_ means getting a single element, which would
be of type `void` if it was allowed.
By extension what the differences between `void`, `ubyte`,
`void[]`, `ubyte[]` really?
`void[]` is supposed to be an array pointing to data of unknown
type. `ubyte[]` is supposed to be pointing to array of data
bytes. The latter might also be used to point to other data
arrays, such as `wchar` arrays, but they are never intended for
pointing to anything that can't safely hold any binary value.
So, if you have pointers, class references, classes, active
reference counters or anything of that sort, it needs `void[]`.
The language-level differences that come to mind:
- You can read individual bytes of `ubyte[]` and change them.
With `void[]` you cannot, unless you cast it to some other array
type first.
- The garbage collector, or the compiler, does not have to treat
data pointed to by `ubyte[]` as potential pointers. With
`void[]`, the type isn't known so any optimisations or garbage
collections have to assume the data might be pointers.
- You won't be able to do much anything with `void[]` in `@safe`
code. `ubyte[]` is very `@safe` friendly though, since it is
assumed there is no danger of overwriting pointers or other type
safety critical data.
