code: conform to c++23 #184
Conversation
This patch still builds with c++17.
| @@ -100,7 +100,7 @@ namespace casual | |||
| if( transcode::utf8::exist( "ISO-8859-15")) | |||
| { | |||
| const std::string source = { static_cast<std::string::value_type>(0xA4)}; | |||
| const std::string expect( u8"€"); | |||
| const std::string expect( "€"); | |||
| const std::string result = transcode::utf8::encode( source, "ISO-8859-15"); | |||
There was a problem hiding this comment.
Är detta bra? Bygger väl på att Eurosymbolen i expect råkar vara en UTF-8 encoded variant av symbolen. Dvs att källkoden editerats i en omgivning som har locale utf-8, och att kompilatorn accepterar denna byte-ström i den locale som gäller vid bygget. Borde man använda "hex-notation" i expected? Har inte läst på om det nya utf-8 stödet i C++20/23 ännu, men antar att det är det som gör at koden behövde ändras för at fungera med både C++17 och C++23... Har köpt Josuttis "C++20 The complete Guide" (700 sidor om C++20, version daterad 2022-11-14) och ser att det finns ett avsnitt i den om ändringarna i utf-8 stödet.
There was a problem hiding this comment.
This is not that great... But u8 prefix creates a std::u8string, witch we don't have any knowledge off in our code base, yet. The source code encoding is in utf8, hence the euro-sign will be a utf8 encoded string, as far as I can understand. The whole u8 prefix is rather confusing, at least to me: https://stackoverflow.com/questions/23471935/how-are-u8-literals-supposed-to-work
It makes more sense now when it creates std::u8string.
There was a problem hiding this comment.
http://wg21.link/p1423 can be of interest.
According to the man page for c++ the g++ compiler takes the default input character set (-finput-charset=charset) from the "locale". If not available there it is assumed to be UTF-8. But it can be specified/overridden on the command line....
For the execution character set (-fexec-charset=charset) the default is UTF-8.
What happens if the input charset is UTF-8 but actual input is "illegal" UTF-8 (e.g. it really is 8859-1 with non-ascii characters) is probably "implementation dependent". According to the stack overflow discussion Clang gives a warning, but g++ just "preserves" the input bytes in this case.
This patch still builds with c++17.