Article

From:
To:
Raoul De Kezel
Subject:
Re: Exceptions vs Error codes
Newsgroup:
borland.public.delphi.objectpascal

Re: Exceptions vs Error codes

In article <✉forums.inprise.com>
	Raoul De Kezel <✉hotmail.com> wrote:

> > If the programmer is worth their salt and aware of exception safety,
> > they should be able to do it without much difficulty.
> 
> Barry, please dont take it bad, but I think this is a pretty naive
> sentence. 

It's pretty easy. Expect exceptions everywhere. Any time you do
anything, think what will happen if an exception occurs right now; most
of the time, nothing much bad will happen.

It's when you have states/modes (like databases; your insert/edit/post etc.) that it gets tricky. Thankfully, I don't do much database programming; Delphi's database architecture almost makes me weep in despair, any time I have to deal with it.
Essentially, all you have to do is write in a transactional style, where every action is either committed or rolled-back based on what exceptions get thrown up by lower layers.
If stuff gets committed, then the typical transaction looks like:
try   // stuff finally   // commit end;
If stuff gets rolled-back if an error occurs, it looks like:
try   // stuff except   // roll back   raise; end;
However, the roll-back mechanism isn't needed often because most of the time the architecture is designed in such a way as to make it implicit:
try   // stuff   // commit here finally   // free stuff; implicitly rolls back if commit was never reached end;
> > Specification of anticipated exceptions is a misguided dead-end.
> 
> That's a very bold statement :-)  

It's a personal opinion, and I feel it very strongly. It goes against my
religion of "expect exceptions everywhere", because it implies that you
only have to expect some exceptions somewhere; to my way of thinking,
that's completely misguided.

-- Barry
--   If you're not part of the solution, you're part of the precipitate. Team JEDI: http://www.delphi-jedi.org NNQ - Quoting Style in Newsgroup Postings   http://web.infoave.net/~dcalhoun/nnq/nquote.html
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Originally created by
Tamarack Associates
Tue, 07 Feb 2023 05:14:12 UTC
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