[erlang-questions] Problem in file:rawopen/2

[Kostis Sagonas]

Matthias Lang wrote:
> Sumith Gamage writes:
> 
>  > I use following code segment to copy directory in Linux.
> 
>  >     {ok, OutFd} = file:rawopen(Dest, {binary, write}),
> 
>  > I used the same code in Windows it fails with the same even with the same
>  > Erlang version (I tried with 5.5.5 & 5.6 both).
> 
>  > Kindly suggest me a workaround for this.
> 
> file:rawopen/2 isn't documented.
> 
> Looking at the library source, there's a comment above rawopen:
> 
> %% Obsolete, undocumented, local node only, don't use!

Matt is of course right in pointing out these, but this really begs the 
questions:

  - Since this function is obsolete, why does it survive across multiple
    OTP releases?

  - Assuming the previous question has a good answer, why aren't such
    functions marked as obsolete so that at least the compiler warns
    for its uses?

Kostis