QString, std::wstring and built-in wchar_t
Qt advises to build your Qt based software without wchar_t as built-in type, just like the Qt libraries themselves. In some cases this is not desired by the environment or not possible because other libraries have been built with the built-in wchar_t type. This will cause obscure linker errors when using std::wstrings, and QString::toStdWString() [qt.io] and QString::fromStdWString() [qt.io].
Windows uses utf-16 for its character encoding, as does Qt. Using this information we can use the following code to work around the issue:
Note that for other platforms the std::wstring may be implemented using uint32 (for ucs-4/utf-32) instead.