Known Bugs and Limitations for units::vector2D Class Library

Compiler Problems

Microsoft Visual C++ 5.0

• Does not support default arguments in template functions, so a tolerance must be provided for similar. You have the option of using the similarTo member function, which does allow a default tolerance.
• Does not support overloading functions which take instantiated template arguments. This means that all "interaction" operators are disabled. For instance, you can't do this:

        Unit2D< Length > length(MetersLength(5),
                                MetersLength(7));
  
        // Compute velocity.
        Unit2D< Speed > velocity = length / SecondsTime(2);
  

  Instead, you must compute the individual components:

        // Compute velocity.
        Unit2D< Speed > velocity(length.x() / SecondsTime(2),
                                 length.y() / SecondsTime(2));
  

Sun Pro CC 4.2

• Does not support default arguments in template functions, so a tolerance must be provided for similar. You have the option of using the similarTo member function, which does allow a default tolerance.

Missing Functionality

• There is no way to format "composite" vector units classes with a single unit subclass. For instance, the following is currently not supported:

        Unit2D< Speed > speed(KnotsSpeed(200), KnotsSpeed(-200));
  
        cout << Speed2DFormat< KnotsSpeed >(speed) << endl;  // error
  

  For now, you must do the formatting yourself:

        cout << '('  << KnotsSpeed(speed.x()).value()
             << ", " << KnotsSpeed(speed.y()).value()
             << ") " << KnotsSpeed::unitsString << endl;