Question

I am writing a QT5 application (with QT Creator) which uses special characters like zodiac signs. This code works perfectly fine on Linux Mint 14:

QString s = QString::fromUtf8(“\u2648”);

But when I compile it on Windows XP SP3 get a compiler warning which says that the current codepage is cp1252 and the character \u2648 cannot be converted. When I run the program this character is displayed as a question mark.

According to my system settings UTF8(codepage 65001) is installed on my Windows.

Answer 1

(Note, I have not tried this, and I don’t know which compiler you are using, and am completely unfamiliar with QT, so I could be wrong. The following is based on general knowledge about Unicode on Windows.)

On Windows, 8-bit strings are generally assumed to be in the current codepage of the system (also called the “ANSI” codepage). This is never UTF-8. On your system, it’s apparently cp1252. So there are actually two things going wrong:

1. You are specifying a Unicode character, which the compiler tries to covert to the correct codepage. On Windows, this results in a compile time error, because cp1252 doesn’t have a code point to represent u+2648.
2. But assuming that the code would compile, it would still not work. You pass this string, which would be in in cp1251 to fromUtf8, which wants a UTF-8 string. As the string is not valid UTF-8, this would likely result in a runtime error.

On your Linux system, both works “by accident”, because it uses UTF-8 for 8-bit strings.

To get this right, specify the 8-bit string in UTF-8 right away:

QString s = QString::fromUtf8("\xE2\x99\x88");