Re: Memory leakage

[Robert Dewar <robert_dewar@my-deja.com>]

In article <3A0230E5.E666B9B8@telepath.com>,
  Ted Dennison <dennison@telepath.com> wrote:
> You cut the original question, which to me is quite clear that
> it is talking about the possibility of having memory leaks in
> an Ada95 program.

I think you miss my point. It is of course possible to write
a program that uses more and more memory and never returns it.
Indeed it is hard to imagine ANY reasonably expressive language
that does not have this property -- note that it is perfectly
possible to create such a program in Java.

If one creates such a program, is it a memory leak? Well from
a purely semantic point of view, one cannot say, since it
depends on whether the programmer intended that the program
behave in this manner.

So there are two questions one can ask:

1) Is the language+implementation free of *inherent* leaks
i.e. leaks that do not relate to specific programmed use of
memory, but are incidental to the implementation. An example
would be a poor implementation of unbounded strings that did
not satisfy the RM requirement of automatic reclamation of
this data, or a tasking implementation that left some storage
behind each time a task terminated or ...

It the intention of the Ada 95 design that a correct
implementation of Ada 95 be free of such leaks.

2) Is the language designed in such a manner that the creation
of programs that constantly increase their memory usage but do
not intend to do so is unlikely?

Well this is of course a far more subjective issue, and most
certainly I do not consider that the original question can
possibly be asking this question, since it talked of such
leaks being impossible, which is of course the wrong kind of
language to use when discussing point 2). One can only talk
of more or less likely.

This is a very important distinction, so I trust it is clear!


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