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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: A suggestion for resource management
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Date: Sun, 22 Aug 2010 08:40:35 +0200
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Date: 2010-08-22T08:40:34+02:00
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On Sat, 21 Aug 2010 23:09:38 +0200, Florian Weimer wrote:

> * Dmitry A. Kazakov:
> 
>> BTW, file handle File_Type should not be opened, it should be
>> constructed. There should be no invalid File_Type,
> 
> There are cases where you need the explicit Close operation, so you
> still end up with an invalid state.

It is difficult to construct such cases. One I can remember is the socket
closed from outside to break blocking recv. 

> How would you handle an exception raised by construction, without
> extending the handler to cover undue regions of code?

Roll back everything elaborated above and propagate.

>>> There are some cases where the destructor solution doesn't really
>>> apply.  For instance, the cleanup operation might need two parameters,
>>> one denoting the object, and a second one decribing where to put it.
>>
>> I would use mix-in in such rare cases. However, I try to avoid clean-ups.
>> It is a bad pattern.
> 
> And you suggest to use Finalize procedures instead?  Hmm.

Yes, it requires a bit more up front work, but it always pays off. It is
much simpler to maintain.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de