Can anyone explain this paragraph of the current C++0x standard draft?

Can anyone explain this statement from ISO N3242 §3.2, 4th point

The added part of n3242 when compare to ISO Standard 2003 :


    4  Exactly one definition of a class is required in a translation unit if the 
       class is used in a way that requires theclass type to be complete.
        A class type T must be complete if:
         - a non-static class data member of type T is declared (9.2), or
         - T is used as the object type or array element type in a new-expression 
         - the type T is the subject of an alignof expression (5.3.6), or
         - an exception-declaration has type T, reference to T, or pointer to T 

Can anyone explain this paragraph of the current C++0x standard draft?

What is the actual meaning of adding this in these statement?

Can any one explain this with the help of an example/program?
Can anyone explain this paragraph of the current C++0x standard draft?
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Can anyone explain this statement from ISO N3242 §3.2, 4th point

The added part of n3242 when compare to ISO Standard 2003 :


    4  Exactly one definition of a class is required in a translation unit if the 
       class is used in a way that requires theclass type to be complete.
        A class type T must be complete if:
         - a non-static class data member of type T is declared (9.2), or
         - T is used as the object type or array element type in a new-expression 
         - the type T is the subject of an alignof expression (5.3.6), or
         - an exception-declaration has type T, reference to T, or pointer to T 

Can anyone explain this paragraph of the current C++0x standard draft?

What is the actual meaning of adding this in these statement?

Can any one explain this with the help of an example/program?