The class must have been derived from MObject in some way. Everything enclosed in the brackets will be passed to the constructor of this class. Constructors which create objects generally use only one argument of the type ConstructArg . We now want to instantiate an object of class C . To examine the construction process we will have a look at the constructor of class C .
P still contains the same text here.
We now go back to the constructor of C . The first three lines should be clear. BuildObject is a member of the class MObject . The BuildObject method will build an object of class A in the same manner as we originally started building our object of class C . The template argument is the class which shall be constructed and the other argument is the ConstructArg of the calling constructor.