std::string num = "0.6"; double temp = ::atof(num.c_str());
Does it for me, it is a valid C++ syntax to convert a string to a double.
You can do it with the stringstream or boost::lexical_cast but those come with a performance penalty.
Ahaha you have a Qt project …
QString winOpacity("0.6"); double temp = winOpacity.toDouble();
If the input data is a
QByteArray::toDouble will be faster.