Why don't we use the CRT functions under Windows?

[IGotD-]

On Saturday, 22 May 2021 at 16:25:08 UTC, Andrei Alexandrescu 
wrote:
> While working with the dmd codebase 
> (https://github.com/dlang/dmd/pull/12560) I noticed that it 
> systematically shuns C runtime calls to functions such as 
> unlink, rename etc. Instead the code uses native Windows API 
> calls (DeleteFile, MoveFile).
>
> Spoke to Walter about it, he said the reason is mostly 
> historical and for the most part forgotten and probably 
> obsolete - at least in the past, Windows implementations of CRT 
> was poorly done, had subtle differences, and bugs.
>
> Is that still the case? If not, we could reduce the complexity 
> of source code considerably by unifying version(Posix) and 
> version(Windows) code.

Instead of trying to unify the code, OS dependent implementations 
should be moved to separate files. Also, should D rely on the C 
library? I would say the D should go the other way and rely on 
the C library a little as possible.

Another thing I have noticed that languages that use the 
C-library just creates a native copy of the interface (which just 
add another layer), instead of defining an own cross platform API