I am learning C++ and was reading copy constructor from the C++: The Complete Reference. The books says that

It is permissible for a copy constructor to have additional parameters as long 
as they have default arguments defined for them. However, in all cases the first
parameter must be a reference to the object doing the initializing.

But I am confused that how we are going to pass those additional parameters? I am sure there should be some way which is not given in the book and which I am unable to figure out. Can anyone help me out?

EDIT: Also is it possible to pass these extra parameters in all three cases i.e.

¦ When one object explicitly initializes another, such as in a declaration
¦ When a copy of an object is made to be passed to a function
¦ When a temporary object is generated (most commonly, as a return value)