Re: [boost] Re: Re: Threads & Exceptions

From: Victor A. Wagner, Jr. (vawjr_at_[hidden])
Date: 2002-08-12 23:37:06

At Monday 2002/08/12 11:48, you wrote:
>----- Original Message -----
>From: "Victor A. Wagner, Jr." <vawjr_at_[hidden]>
> > At Monday 2002/08/12 09:44, you wrote:
> > >From: "Victor A. Wagner, Jr." <vawjr_at_[hidden]>
> > > > I assert that using an "underlying library" to cause main to be
>executed
> > > > again is NO different than calling it directly!
> > >
> > >I never asserted that the "underlying library" caused main to be executed
> > >_again_.  In fact, that's not at all what occurs.
> >
> > I was referring to your example which you claimed couldn't be done
> > portably... as I recall it made a thread and pointed the execution address
> > &main
>
>Uhmmm... you recall incorrectly then.  I would never have done that, as it's
>illegal.  The example I posted didn't do this.

you are, of course, correct
In my haste, I didn't recognize your use of the name main (in function 
main) where it should be _obvious_ (sarcasm intended) that it couldn't 
possibly be mistaken for the address of a function.

"
>>   boost::thread* main = new thread();
>>   boost::thread thrd(boost::bind(&my_thread, main));
"
I have no idea why you (in your admitted haste) even considered such an 
abomination.

> > > > If the standard is silent on a subject (and apparently it's exactly
>like
> > > > the tar baby with respect to threads) we should be able to choose a
> > > > behavior that isn't wildly at odds with the rest of the standard (i.e.
> > > > causes no real surprises).
> > >
> > >Only if the non-standard threading extensions explicitly allow it.
> >
> > I'm suggesting as strongly as possible that they SHOULD allow it.
>
>But they _don't_.  That's the point.  They are mute on the subject, mostly
>because they are C APIs.  This puts C++ developers in very murky waters, and
>they have to be very careful that what they do doesn't violate the rules for
>either the standard, or the library, and then hope (with reasonable
>assurances that it will) that things work the way they expect. That's why
>Boost.Threads came into being... to explore the dark corners, provide
>reasonable solutions today, and find which such solutions would be better
>implemented differently with language support.

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.

as an aside, I _detest_ coding to the "lowest common denominator" which we 
appear to "have" to do.

> > > > >>You certainly bandy about the old standard when it suits your
>purpose
> > >and
> > > > >>I believe you have mis-read it miserably in an attempt to justify a
>poor
> > > > >>decision on your part (not allowing exceptions to be passed back).
> > > > >
> > > > >Where have I misread it?
> > > >
> > > > I have no idea where you misread it.
> > >
> > >Then stop making baseless accusations.
> >
> > it's not baseless. you've come to what I believe to be an erroneous
> > conclusion from somewhere!
>
>If you can define what's erroneous, let alone how it's erroneous, then the
>accusation is baseless.  Believing I'm wrong is not the same thing as
>proving I'm wrong.

no kidding.... OJ isn't in jail.

>   You could reword what you just said as an opinion, and I
>wouldn't object (though I'd still ask you to do the leg work to prove me
>wrong), but as it is you're not stating opinions but accusing me of
>something you can't prove.  That's a baseless accusation.

Ok, it is my opinion that there is nothing in the standard (that has been 
presented thus far) that would preclude implementing the separation of call 
and return to/from a function via a thread mechanism, and that furthermore 
exceptions _could_ be passed back when the return from the function was 
instantiated.

> > > > You seem to think that some clause about uncaught exceptions in main()
> > > > applies to uncaught exceptions in another thread.
> > >
> > >I never made that claim.  Better calm down and go back and read what I
>*did*
> > >say.
> >
> > I can see we're both getting somewhat exasperated by this... a more useful
> > response would have been
> > "Better calm down and re-evaluate what 'blah blah (what you *did* say)'
> > means".
> > I'll go re-read the thread and see where I've misunderstood you.
>
>Sorry, I did get a little carried away myself here, but I was backed into a
>corner by the baseless accusations.  Still should have kept myself in check
>though.
>
>Bill Kempf
>_______________________________________________
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Victor A. Wagner Jr.      http://rudbek.com
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