Re: memory management and productivity

["Robert I. Eachus" <rieachus@comcast.net>]

Hyman Rosen wrote:

> I believe, but I'm not sure, that in Ada if a pointer *type* (not
> a pointer object) goes out of scope, then all objects of that type
> are deallocated.

Hmmm, a better description is that if a type goes out of scope, all 
objects of that type are deallocated.  If a storage pool goes out of 
scope, all objects in the pool are deallocated. If an access type goes 
out of scope though, nothing special happens.

It is easiest to see this by thinking about:

declare
   type Foo is private;
   Foob: Foo;

   procedure Fubar(F: in Foo) is
     type Bar is access all Foo
     B: Bar := F'access;
   begin null end;
begin
   Fubar(Foob);
end;

Obviously you don't want Foob to be deallocated when Bar goes out of 
scope.  B will be deallocated when Fubar returns, but that is because B 
goes out of scope, not Bar.


-- 

                                           Robert I. Eachus

"Reason and experience both forbid us to expect that national morality 
can prevail in exclusion of religious principles." -- George Washington