Re: Free'ing extended types

[Laurent.Guerby@enst-bretagne.fr (Laurent Guerby)]

Robert Dewar writes
: Jonas said
  ^^^^^ 

   Jonas posted my email  ;-).
: "   So there's nothing that could lead  to an erroneous execution
: (note
: the X.all'access, the libc then does what's needed)."
:
: You seem to have the wrong idea of what erroneous is about. An erroneous
: execution is one whose semantics is not specified by the reference
: manual. You seem to think this means that it wlil blow up or do 
: something wrong. Not at all! It *may* blow up but it does not have to!
: 
: You can look at the execution of a particular impementation and conclude
: that a particular erroneous execution will have no ill effect on that
: implementation, but that does not mean that the exeution is not erroneous!

   I think you missed my answer, I was just saying that, in this case,
the "erroneous execution" was implementation dependant :
 
"  I *think*  that  it   (erroneous/not erroneous)  is  implementation
dependant, because   for each access   type  the Storage_Pool  (if not
user-specified) is  choosen "in an implementation-defined manner", see
13.11(17)."

   And I was pointing out the GNAT sources showing  (I'm not 100% sure
of my interpretation here) the use of one Storage_Pool (coded from the
C  library)  for    all  these types.  My   conclusion   was  that the
construction was not erroneous for the GNAT compiler.

   If another Ada  compiler use different  pools for the  types in the
example, as permitted by the  RM 13.11(17), then  the execution of the
construct is erroneous. Then, of course, it can just work, don't work,
crash your disk or nicely dies with Program_Error ;-).
 
-- 
--  Laurent Guerby, student at Telecom Bretagne (France), Team Ada.
--  "Use the Source, Luke. The Source will be with you, always (GPL)."
--  http://www-eleves.enst-bretagne.fr/~guerby/ (GATO Project).
--  Try GNAT, the GNU Ada 95 compiler (ftp://cs.nyu.edu/pub/gnat).