Giuseppe "Cowo" Corbelli ...

I'm an happy user of Boost libraries and recently I had to mess with QT libraries.
I didn't really like the QString-to-number conversion features of QString class because of the clumsy error checking mechanism, so I wrote a little wrapper for boost::lexical_cast.
Unfortunately boost::lexical_cast is not written with extensibility in mind so a temporary std::basic_string variable is required to perform the magic (or at least I couldn't find a better, unobtrusive way).

namespace boost { namespace detail {

#ifndef DISABLE_WIDE_CHAR_SUPPORT
inline bool operator>>(boost::detail::lexical_stream<QString, std::wstring>& in, QString& output)
{
    std::wstring tmp;
    in >> tmp;
    output = QString::fromStdWString(tmp);
    return true;
}
#endif

template<typename Source>
inline bool operator>>(boost::detail::lexical_stream<QString, Source>& in, QString& output)
{
#if defined(BOOST_NO_STRINGSTREAM)
    in << '\0';
#endif
    std::string tmp;
    in >> tmp;
    output = QString::fromStdString(tmp);
    return true;
}

}}

This allows you to write something like:

QString x("123");
int id(boost::lexical_cast<int>(x));