There are several features in C++ which moc does not support. CopperSpice was written to maintain the advantages and power of Signals and Slots, without the limitations moc introduced. The new functionality added to C++11 was required in order to redesign moc.

The following is a list of what is lost in C++ when using moc. Except where noted CopperSpice does not have any of these restrictions.

Class templates can not contain Signals or Slots
Nested classes can not have Signals or Slots
A macro can not be used to declare a Signal or a Slot
Macros can not be used to define a base class for a QObject
Macros can not be used to define the data type for Signal and Slot parameters
Multiple inheritance requires QObject to be the first parent
- With multiple inheritance, moc assumes the first inherited class is a subclass of QObject
- CopperSpice allows QObject inheritance in any position
Virtual inheritance with QObject is not supported
Signal or Slot parameters can not use function or method pointers
Enums and Typedefs must be fully qualified for Signal and Slot parameters
- When checking the signatures of Signals and Slots, QObject::connect() compares the data types as strings. For example, double and qreal are treated as different types even though qreal is a typedef for double.
- CopperSpice removes this limitation when using method pointers for the Signal and Slot parameters in QObject::connect()