keagchon@mehta.anu.edu.au (Geoff Keating 9205156) writes:

>The draft WP says that [section class.cdtor:3]

>  When  a  virtual function is called directly or indirectly from a con-
>  structor (including from its ctor-initializer) or from  a  destructor,
>  and the object to which the call applies is the object under construc-
>  tion or destruction, the function called is the  one  defined  in  the
>  constructor  or destructor's own class or in one of its bases, but not
>  a function overriding it in a class derived from  the  constructor  or
>  destructor's  class, or overriding it in one of the other base classes
>  of the complete object (_intro.object_).

>Why allow this, rather than refusing calls to virtual functions at
>all? It would be nice to say that `if I override this function, then
>the old version will _never_ be called on objects of this type'.

In general the compiler CANNOT diagnose a call to a virtual function
from a constructor or destructor - the call might very well come from
a non-virtual function in a separate compilation unit.

In view of this, the specification in the standard that the virtual
function call be treated as if the actual object were of the type of
the constructor or desctructor currently being executed is certainly
within reason.
--
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The draft WP says that [section class.cdtor:3]

  When  a  virtual function is called directly or indirectly from a con-
  structor (including from its ctor-initializer) or from  a  destructor,
  and the object to which the call applies is the object under construc-
  tion or destruction, the function called is the  one  defined  in  the
  constructor  or destructor's own class or in one of its bases, but not
  a function overriding it in a class derived from  the  constructor  or
  destructor's  class, or overriding it in one of the other base classes
  of the complete object (_intro.object_).

Why allow this, rather than refusing calls to virtual functions at
all? It would be nice to say that `if I override this function, then
the old version will _never_ be called on objects of this type'.

--
-Geoff Keating (keagchon@mehta.anu.edu.au)

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