[Development] Qt6: Adding UTF-8 storage support to QString

[Thiago Macieira]

On Friday, 18 January 2019 07:26:51 PST Tor Arne Vestbø wrote:
> If we plan to standardise on our Qt source code being UTF8, can we please
> allow QString(“Tor Arne Vestbø") without going through
> QLatin1Literal/QStringLiteral/QLatin1String/etc etc?

I think we now can. The last problem we had was MSVC pre-2015 update 2, which 
added the /utf-8 switch. Without that option, any non-ASCII character in the 
source code, even in comments, could cause compilation errors by causing a 
decoding error in whichever codepage the user used in his/her OS.

I think all our builds now use /utf-8, which means UTF-8 is permitted 
everywhere now. You can use it in comments ("Copyright Klarälvdalens ...", for 
example) and in strings. Please don't use it in identifiers.

As for strings, the QString constructor takes UTF-8 input, but however fast 
the decoder is, it's still slightly slower than the Latin1 decoder. So if your 
string is purely US-ASCII, using QLatin1String is recommended.

PS: we don't need SG16's char8_t, but we'll need to add support for it.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center