DIP33: A standard exception hierarchy

[John Colvin]

On Monday, 1 April 2013 at 12:12:56 UTC, Lars T. Kyllingstad 
wrote:

> But if all cleanup code is bypassed, what is the point in using 
> the exception mechanism in the first place?  Why not just 
> abort() and be done with it?
>
> I can think of two reasons for throwing an Error rather than 
> aborting directly:
> 1. You want a kind of "graceful" shutdown, in which destructors 
> *are* called and make their best attempt at cleaning things up.
> 2. You want to catch it at some point, and perform some manual 
> cleanup.
>
> But if (1) does not happen, can you even hope to do something 
> useful with (2)?  Your program is in the worst possible state 
> it can be!

I'm no expert on these things, but:

Any chance of being in an invalid state - > undefined behaviour

Undefined behaviour - > your destructors/cleanup routine could in 
theory do anything.

Therefore, you're better off not trying to cleanup if program 
state could be invalid.


Anything that doesn't signal a possible invalid state should be 
sensibly catchable and run destructors etc. , anything that does 
should cut through the program like a knife and is catchable at 
your own risk.