Google's Go & Exceptions

[Andrei Alexandrescu]

Nick Sabalausky wrote:
> Nick Sabalausky wrote:
>>> ""J?r?me M. Berger"" <jeberger at free.fr> wrote in message
>>> news:hjnrhv$1l0k$1 at digitalmars.com...
>>>> Throwing exception inside constructors should be avoided because
>>>> then the destructor is never called and you risk leaking like crazy.
>>> That's a risk outside of constructors too. Hence:
>>>
>>> scope(failure) {}
>>>
>> - This doesn't exist in C++;
> 
> Well, I was really only talking about D. I guess the answer to "Should 
> throwing exceptions in a constructor be avoided?" is "Depends on the 
> language." For C++, constructors have historically had a number of tricky 
> edge cases (though I couldn't really remember what), so I'm not surprised 
> that throwing exceptions is one of them. For D though, I'm not sure I see 
> that there's a problem.

The edge cases involve member initialization that throws. The root of 
the matter is that in C++ you can't have a type with a guaranteed 
nothrow constructor. That makes a lot of things very difficult when it 
comes to object composition.

I've aired a number of times the idea that the parameterless constructor 
should not throw. That would simplify many issues, but there are still 
cases when that doesn't work (nonull!!!)


Andrei