Re: Does memory leak?

[hbaker@netcom.com (Henry Baker)]

In article <1995Mar24.123006.9471@eisner>, kilgallen@eisner.decus.org
(Larry Kilgallen, LJK Software) wrote:

> In article <hbaker-2303951759400001@192.0.2.1>, hbaker@netcom.com (Henry
Baker) writes:
> 
> > Most serious Ada compilers try pretty hard not to leak from internal leaks. 
> > However, objects that you allocate yourself with 'new' are considered your
> > problem.  Huge amounts of network, conference and newsletter bandwidth
have been
> > wasted on trying to get around the fact that Ada doesn't provide a built-in
> > solution to this problem.
> 
> From the Ada83 manual "An implementation may (but need not) reclaim the
> storage occupied by an object created by an allocator, once this object
> has become inaccessible."
> 
> The next section describes the CONTROLLED pragma to forbid implementations
> from reclaiming memory except when leaving the innermost "block statement,
> subprogram body or task body" enclosing the type declaration.
> 
> Is the complaint that Ada should force implementors to reclaim storage,
> or that when the CONTROLLED pragma is not used, implementations should
> take a less conservative approach than waiting to exit the scope of the
> type declaration?

Ada83 took a 'see no evil, hear no evil,...' approach to storage management.
Therefore, some of the vendors initially took the same (sloppy) attitude --
e.g., Rational, Telesoft, etc.

It actually takes a great deal of sophistication for a language to offer
automatic, safe, flexible, customizable memory management protocols -- this is
probably why NO language today offers such a collection of features.

From the Ada rationale and the design of Ada, it was clear that automatic
garbage collection was preferred and intended, but never implemented due
to a veto from the intended embedded user community.  Unfortunately,
this left Ada in a never-never land where it didn't have _either_ automatic
storage management _or_ not-so-automatic storage management.

This general lack of 'fit and finish' in Ada83 seems more appropriate for
consumer products from the old Soviet Union than one from the U.S.A.  Given the
nature of the process which produced Ada83, perhaps there is a lesson here??

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