Pointers-to-data members

[Mark Mitchell]

We haven't specified a way to represent a NULL pointer to data member.
All we have is:

  A pointer to data member is an offset from the base address of the
  class object containing it, represented as a ptrdiff_t. It has the
  size and alignment attributes of a ptrdiff_t.

G++ presently adds one to the offset, allowing zero to serve as the
NULL pointer to member.

--
Mark Mitchell                   mark at codesourcery.com
CodeSourcery, LLC               http://www.codesourcery.com