unicode character cannot be converted to cp1252 - qt

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:
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.
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");

Answer 2

Here is my advice to get everithing work fine:
There is only one encoding type UTF-8! Use it everywhere if possible. So, in QtCreator settings set default codepage for sources UTF-8.
You can convert your source code in QtCreator: edit -> choose encoding and there reload in codepage. If it can't be done, use linux console application iconv this way:
iconv -f cp1252 -t utf-8 your_source_in_cp1251.cpp > your_source_in_utf8.cpp
I use this code snippet for C-strings in my source codes: in main.cpp add #include <QTextCodec>, and then do:
// For correct encoding
QTextCodec *codec = QTextCodec::codecForName("UTF-8");
QTextCodec::setCodecForCStrings(codec);