Marco van de Voort schrieb:
In our previous episode, Hans-Peter Diettrich said:
IMO Weak references should be reserved for users who accept possible
consequential problems, but should never be used in standard libraries.
At least I'd suggest to make weak references subject to an compiler
switch, so that every user has a chance to disable them in case of trouble.
IMHO weak references trade one manual memory system in for a different
manual memory system.
Weak references steer/guide *automatic* memory management.
The hard part of manual memory systems, figuring out how a complex dynamic
structure deallocates (that is usually tackled by having a bit of design and
thought go into it), remains.
And this is what the user of such a structure (standard libraries...)
does not always know. He may be unable to determine the reason for some
runtime error in his code, when an object was destroyed automagically
where it should still be alive. The user can debug (and fix) ordinary
(owner/owned) patterns, implemented in high level code, but not
table-driven (RTTI) or otherwise hidden (intrinsic) management
procedures. While the user can change the owner of an object at runtime,
he cannot change a weak reference into a strong one, without
recompilation of at least the unit containing that declaration, and
without figuring out the consequences of such an change.
DoDi
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