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Date: Fri, 15 Mar 2002 11:00:01 -0500
From: Hyman Rosen <hyrosen@mail.com>
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Newsgroups: comp.lang.ada
Subject: Re: memory leakages with Ada?
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Date: 2002-03-15T11:00:01-05:00
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John McCabe wrote:
> One of the things I've found recently, since starting to use C++ more,
> is that Ada.UncheckedDeallocation is so much nicer than 'delete' as it
> returns you a nice, null pointer! 'delete' in C++ appears to remove
> the allocated block, but leave your pointer pointing to where it used
> to be!

If I'm not mistaken (not really knowing Ada), Ada.UncheckedDeallocation
is a generic procedure which must be instantiated for each access type
you are interested in freeing. So if you want that behavior in C++, you
should have no qualms about adding your own procedure in the same way.

template<typename T>
void unchecked_deallocation(T *&p) { delete p; p = 0; }

The counter argument is that dangling pointers are a problem where they
have been copied into other data structures, so nulling one particular
variable which is holding the pointer isn't all that useful. Also,
freeing memory tends to happen as part of the process of cleaning up a
data structure which is itself about to disappear, so again nulling the
pointer isn't going to accomplish much.