• Convert str to the corresponding return type.
• str might be a string of type string or wstring.
• Skip leading whitespace.
• If idxRet!=nullptr, it returns the index of the first character not processed for the conversion.
• base allows you to specify a base number.
• Might throw std::invalid_argument if no conversion is possible and std::out_of_range
if the converted value is outside the range of representable values for the return type.