From: Victor A. Wagner, Jr. (vawjr_at_[hidden])
Date: 2002-08-13 16:01:46
At Tuesday 2002/08/13 12:37, you wrote:
>From: "Victor A. Wagner, Jr." <vawjr_at_[hidden]>
> > At Tuesday 2002/08/13 08:02, you wrote:
> > >From: "Victor A. Wagner, Jr." <vawjr_at_[hidden]>
> > > > At Monday 2002/08/12 11:48, you wrote:
> > >[deleted]
> > > > I'm not sure that language support is all that's needed. Tho I really
> > >wish
> > > > _some_ HLL would get around to having a swap operator (declaring it
> > >needing
> > > > to be atomic would be ++good) it might even be sufficient.
> > >
> > >I don't follow your thinking here, but I get the feeling you don't
> > >comprehend the issue.
> > The only language deficiency I see (and it's a show stopper) is the lack
> > a way to specify an atomic set/test.
> > Since an atomic set/test is necessary for synchronization, and an atomic
> > swap can be used as a set/test, I was just commenting that its inclusion
> > may suffice to solve the problem.
>Again, I don't understand your thinking. I don't see how the issue at hand
>(unhandled exceptions in the main thread resulting in terminate() being
>called, possibly with out thread unwinding) can be solved by a set/test,
>atomic or not. I also don't see how synchronization plays a part here
The ONLY complaint I've heard you voice is "race condition"... later you
mentioned "without language support"
This may not directly bear on something _I_ never considered a problem in
the first place...attempting to propagate an exception out of the "main
program". I thought it bore on your worries about polling and "race
> > > > as an aside, I _detest_ coding to the "lowest common denominator"
> > > > appear to "have" to do.
> > >
> > >It's not a "lowest common denominator" issue. The problem at hand here
> > >undefined by ALL the APIs, as well as the C++ standard.
> > And we're refraining from defining something because we fear that the
> > "Gazorninplatz IV" compiler/library won't be able to what we specify. For
> > reasons I don't understand, "lowest common denominator" seems to be the
> > idiom when in fact we should be saying "greatest common denominator".
>I believe a large majority of compilers will prevent us from solving the
>issue, regardless of what's defined or undefined behavior. That aside,
>though, I still don't think you can claim this to be a "lowest common
>denominator" idiom, since it's undefined behavior on ALL platforms.
I infer that "it's" means un handled exceptions in the main thread (I say
again, something that I've not been considering)
> > >And this is what I think clinches that you don't understand the issue at
> > >hand. I never claimed there was anything that precluded the separation
> > >call and return to/from a function via a thread mechanism. Or that
> > >exceptions could be passed back when the return from the function was
> > >instantiated. I claimed that the concept could not be applied _to the
> > >thread_, because that results in an explicit call to terminate(),
> > >with out stack unwinding, no less.
> > Since it is _illegal_ for a user to "call" main() (thanks for pointing
> > out, tho I'm puzzled at the committee's thinking here), I don't see why
> > this is relevant.
>Because of the defined behavior of thread_exit().
ok, this sounds like another giant misunderstanding.
if an exception is thrown in the "main thread" and it is uncaught, do
whatever you wish.
I don't care.
I've never cared (well, formatting my primary drive would irk me a lot).
That never was the point of the discussion (from MY pov anyway... another
misunderstanding we appeared to have).
The only reason I got into the discussion was I perceived you to say that
an "uncaught exception" from ANY thread was best handled by termination of
the program (again, probably something I mis-inferred).
That's all I want to stop.
What I want to _continue_ is an agreement that _some_ mechanism for
allowing exceptions to be passed (via join() if that's how one retrieves
status about a thread) in addition to (instead of?) some "return value".
It would disappoint me if I had to alter a function in order to implement a
"delayed call" or whatever term we're going to use to describe this feature.
It's also obvious (to me) that we canNOT possibly pass all possible
exceptions, I suggested a set, and volunteered to assist in writing the code.
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Victor A. Wagner Jr. http://rudbek.com
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