Re: [c++-pthreads] Re: thread-safety definition

[Ross Smith <r-smith@xxxxxxxxxx>]

On Tuesday 13 January 2004 02:41, Dave Butenhof wrote:
>
> I think I disagree, at least philsophically, with the
> characterization of the model as "fragile". But I think I also
> understand what you mean; and the problem isn't with the model, but
> rather with the effect of that model on existing code that
> all-too-casually and agressively eats exceptions it doesn't
> understand. I think there are vanishingly few circumstances where a
> blind catch(...) without an unconditional re-throw should be
> considered "legitimate".

I'm beginning to get the same worried feeling Wil Evers expressed a few 
messages back. It sounds as though a lot of people are seriously 
considering the idea of allowing exceptions to escape from destructors.

Dave, while I have the greatest respect for your knowledge and 
understanding of threads, I think the above shows that you don't really 
understand C++. Please try to understand that it is _absolutely vital_ 
that destructors never be allowed to throw under any circumstances. If 
a destructor calls a function that may throw some unknown exception (a 
very common case, especially in template classes whose destructors will 
often call member functions of some arbitrary user-supplied type), the 
call _must_ be wrapped in a catch-and-discard-all block. At most you 
can log the error somewhere.

Any attempt to standardise a solution that doesn't take "Destructors 
Must Not Throw" as axiomatic is simply going to be a non-starter as far 
as C++ programmers are concerned. I'd really like to see this list 
explicitly address this issue rather than continuing to casually talk 
about uncatchable exceptions and similar horrors.

-- 
Ross Smith ......... r-smith@xxxxxxxxxx ......... Auckland, New Zealand

    "This world is like a burnt steak: small, tough, and the chips
    are always stacked against you." -- Mike