Re: Does memory leak?

[RTOAL@lmumail.lmu.edu (Ray Toal)]

In article <3ls2ku$qls@hacgate2.hac.com> jbaker@thor.tu.hac.com (John Baker) writes:


>Henry Baker (hbaker@netcom.com) wrote:
>: In article <3l6gf6$h05@theopolis.orl.mmc.com>, Theodore Dennison
>: <dennison@escmail.orl.mmc.com> wrote:

>: > Perhaps I'm missing something here...what exactly is wrong with using 
>: > UNCHECKED_DEALLOCATION?
>: > 
>: > I mean, if you don't deallocate what you allocate, your program will
>: > leak memory no matter what language it is written in. This isn't an Ada
>: > issue, it's an issue of sloppy coding.

>: Not necessarily true.  I've written lots and lots of Lisp programs, and
>: I think that I forgot to deallocate in almost all of them.  They worked
>: just fine.

>: (Of course I'm being facetious.  Lisp doesn't have a deallocate primitive,
>: because it has an automatic garbage collector, just like Modula and Eiffel.
>: Furthermore, garbage collection can't collect stuff that is still linked
>: to live objects, so you can still get a 'leak' this way.)

>The Lisp i programmed in (symbolics) had a really nice feature --
>allocation to *named* areas of memory.  You could allocate
>objects with differing life spans in different areas and then
>(at the appropriate time), wipe a whole named area and start over
>without having to destroy the objects individually.  Very fast
>and easy to control.  I'd like to see a feature like that in C++
>and ADA.

>JB

Certainly they exist, but you have to write them yourself.  In C++
you can overload the 'new' operator to allocate to your own arenas.
Ada suggests that implementations manage the "heap" as a collection
of pools that "belong to" specific access types; since this is only
implementation advice you may have to simulate this yourself if your
compiler supports neither automatic garbage collection or pools.
You can in any modern language define a particular array to use for
allocation of certain objects and write an allocation procedure.
In fact, it is a good idea because a memory pool in which all objects
are of the same size is not subject to fragmentation and allocation/
deallocation is O(1).

Ray Toal