[Issue 23186] wchar/dchar do not have their endianess defined

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23186

--- Comment #3 from Dennis <dkorpel at live.nl> ---
(In reply to Richard Cattermole from comment #2)
> No, this isn't an ABI thing, it's about encodings.

I don't follow, do you have a reference for me? I'm looking at:

https://en.wikipedia.org/wiki/UTF-16

"Each Unicode code point is encoded either as one or two 16-bit code units. How
these 16-bit codes are stored as bytes then depends on the 'endianness' of the
text file or communication protocol."

The `wchar` type is an integer, the 16-bit code. No integral operations on a
`wchar` reveal the endianness, only once you reinterpret cast 'the text file'
(a `ubyte[]`) will endianness come up, but at that point I think it's no
different than casting a `ubyte[]` to a `ushort[]`. We don't have BE and LE
`short` types either.

> However, it can be kept pretty simple something like `Unicode 8-bit code
> point with matching target endian`.

There's no endian difference for 8-bit code points, or are we talking about bit
order instead of byte order?

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