Re: Is this ok to do?

=?ISO-8859-15?Q?Marcel_M=FCller?= <>
Fri, 20 Apr 2012 13:20:47 +0200
On 20.04.2012 08:17, Juha Nieminen wrote:
[delete this;]

   Personally, I would still try to avoid that kind of situation and try
to think of a better design. Even if it works, it makes understanding the
inter-class dependencies and the program flow more complicated. When
reading code, one doesn't expect that the underlying object pointed by
'this' will suddenly disappear. (Adding a comment saying so in each line
where this (might) happen is only slightly alleviating the problem, and
prone to be skipped.)

You may be right, but for self-managing objects I did not find a better
solution so far.

Think of dialog backend classes. Closing the dialog will obviously make
the backend object orphaned. So it is straight forward to delete the
backend a last action. And if public references to the backend classes
are allowed then reference counting is a suitable solution. Of course,
decrementing my own reference counter might still invoke delete this.

Any other solution requires some kind of common, static instance manager
that keeps track of all objects and has some kind of garbage collection.
This instance managers almost always involve threading issues and
sometime initialization sequence problems. Personally I prefer that the
backend class for a certain dialog has a static factory to show the
dialog. It is up to the implementation whether this is a singleton or not.


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