Encoding issue.

[Adam D. Ruppe]

On Saturday, 4 July 2020 at 15:16:22 UTC, Jowei Dei wrote:
> Is there any good way to convert my console input to the
> internal string of D?

The best thing to do is to use the wide-char versions of the 
Windows API

http://dpldocs.info/this-week-in-d/Blog.Posted_2019_11_25.html#tip-of-the-week

Notice the ReadConsoleW and WideCharToMultiByte function calls. 
ReadConsoleW reads input from the windows console as utf-16 wide 
chars. You can use those directly in D as the type `wstring` or 
you can convert them to plain utf-8 string via the 
WideCharToMultiByte function as seen in the example code in my 
blog.


You could also do some conversions like changing the console code 
page (I do NOT recommend this) or converting from the current 
code page to UTF8. The other answer suggested SetConsoleOutputCP; 
this is for output, and since you need input, the function is 
SetConsoleCP. 
https://docs.microsoft.com/en-us/windows/console/setconsolecp

Just while that looks like the easiest way, it changes a global 
setting in the console that remains after your program returns 
and is subtly buggy with regard to font selection, copy/paste and 
other issues.


To convert input yourself, use this function to get the current 
console code page:

https://docs.microsoft.com/en-us/windows/console/getconsolecp

And pass that as the CodePage argument to MultiByteToWideChar

https://docs.microsoft.com/en-us/windows/win32/api/stringapiset/nf-stringapiset-multibytetowidechar


This gives you a `wstring`.


But really better to just let Windows do this for you by calling 
ReadConsoleW to get the input in the first place. This works in 
all console cases and avoids the bug. Only worry here is it does 
NOT work if the user pipes data to your program

other_program | your_program.exe

will fail on ReadConsoleW. So you will have to check that in an 
if statement and change back to readln or whatever. My first blog 
discusses this in more detail.