How to ensure string compatibility In D？

[FrankLike]

On Tuesday, 22 January 2019 at 21:49:00 UTC, bauss wrote:
> On Tuesday, 22 January 2019 at 19:14:43 UTC, Jonathan M Davis

> Is there a reason we cannot implement toStringz like:
>
> immutable(TChar)* toStringz(TChar = char)(scope const(TChar)[] 
> s) @trusted pure nothrow;
> // Couldn't find a way to get the char type of a string, so
"core.sys.windows.windows.winbase"，it's implementation is a good 
choice.
> couldn't make the following generic:
> immutable(char)* toStringz(return scope string s) @trusted pure 
> nothrow;
> immutable(wchar)* toStringz(return scope wstring s) @trusted 
> pure nothrow;
> immutable(dchar)* toStringz(return scope dstring s) @trusted 
> pure nothrow;


For example:
/////////////////////////////////START//////////////////////////////////////
import core.sys.windows.windows;
import std.stdio;
import std.string;
import std.conv;

void main()
{
	auto	strA_Z ="CD"w;
	auto type = GetDriveType((to!wstring(strA_Z[0])~":\\"w).tos);
	writeln(to!wstring(strA_Z[0])~" is ",type);
}

private auto tos(wstring str)
{
  version (ANSI)
  {
	writeln("ANSI");
	return cast(const(char)*)(str);
  }
  else
  {
	writeln("Unicode");
	return cast(const(wchar)*)(str);
	
  }
}
private auto tos(string str)
{
  version (ANSI)
  {
	writeln("ANSI");
	return cast(const(char)*)(str);
  }
  else
  {
	writeln("Unicode");
	return cast(const(wchar)*)(str);
  }
}
/////////////////////////////////END//////////////////////////////////

It's work ok.