+
+ \begin{describe}{msg}[obj.teardown]{int teardown();}
+ Teardown an instance which is no longer required.
+
+ The message returns an integer flag. A zero value means that the
+ instance is safe to deallocate. A nonzero value means that the instance
+ should not be deallocated, and that it is safe for the caller to simply
+ forget about it. This simple protocol may be used, for example, to
+ implement a reference-counting system.
+
+ This message uses a custom method combination which works like the
+ standard method combination except that default behaviour is invoked if
+ no primary or around method overrides.
+
+ This default behaviour is to execute each superclass's teardown
+ fragments, most specific first, and then return zero to indicate that the
+ object is ready for deallocation. Teardown fragments defined by the same
+ class are processed in the order in which they appear in the class
+ definition.
+
+ It is usual to provide complex teardown behaviour as @|before| methods.
+ Logic to decide whether to allow deallocation is usually implemented as
+ @|around| methods.
+ \end{describe}