Does memory leak?

[sands@clipper.ens.fr (Duncan Sands)]

Does Ada leak memory?  I would like to believe it doesn't, but
how does it manage not to (without having to use unchecked
deallocation)?

For example, if I have a pointer to a block of memory, and I set
that pointer to null, in simple cases I am ready to believe that
the compiler knows I'm finished with the block... but if the
pointer is to a complicated self-referential structure, some sort
of black magic seems needed to work out whether I'm really
finished with that structure or not.  Can this truly be done
efficiently?

You can see that I know nothing about how garbage collection works,
and precious little about what Ada requires for memory management.
I suspect I'm not the only one.  If someone could demystify all this
for me, I would be very grateful...

Thanks a lot,

Duncan Sands.