RE: [boost] Re: Re: Attempting resolution of Threads & Exceptions Issue

From: David Bergman (davidb_at_[hidden])
Date: 2002-08-13 11:16:49

Eric,

It might be quite hastily written, yes. It is quite hard to know where
to start with this beauty C++, so I can't blame him. It is hard to find
that thread, dealing with (1) generic programming, (2) meta programming
(as the Boost community refers to the type-based programming using
templates), (3) object-orientation (hey, did everybody forget that
methodology?), (4) the language syntax....

The Josuttis reference is certainly *not* a reference in the strict
sense of the word, but I could perhaps recommend it as a first
introduction to STL (although I would probably prefer The C++
Programming Language, 3rd Ed., by Strousrup).

I think a good introduction to the meta programming techniques that have
been so dominating the last few years in C++ is found in the Haskell or
Standard ML environments. There you have the type manipulation cleared
from other, orthogonal constructs, and strange syntax (I think only the
die hard C++ fan can view the definition part of the C++ syntax clear
and concise...).

/David

-----Original Message-----
From: boost-bounces_at_[hidden]
[mailto:boost-bounces_at_[hidden]] On Behalf Of Eric Woodruff
Sent: Tuesday, August 13, 2002 11:58 AM
To: boost_at_[hidden]
Subject: [boost] Re: Re: Attempting resolution of Threads & Exceptions
Issue

I was referring to Josuitti's STL reference. Maybe it's just the wording
/
writing style, but I can't stand it and I found some of it to be
incomplete
if it is to be used for anything besides leisure. I have to give the
book
some credit though, because the STL is quite complicated, and some
references to tend to contradict eachother.

I just seemed to make more progress with an online search engine.

----- Original Message -----
From: David Bergman
Newsgroups: gmane.comp.lib.boost.devel
Sent: Tuesday, 2002:August:13 10:59 AM
Subject: RE: Re: Attempting resolution of Threads & Exceptions Issue

Eric,

Stroustrup has had his back-and-forths regarding exceptions...

It is rather strange, although positive that he says what you state,
which is something I have also tried certain people to understand here.
Termination is the "good ol'" way of dealing with really exceptional
behavior, which should indeed be frown upon. Agree.

By the way, which reference book was you referring to? The one by
Josutti or The C++ Programming Language (third ed.?) by Strousrup?

/David

-----Original Message-----
From: boost-bounces_at_[hidden]
[mailto:boost-bounces_at_[hidden]] On Behalf Of Eric Woodruff
Sent: Tuesday, August 13, 2002 9:24 AM
To: boost
Subject: [boost] Re: Attempting resolution of Threads & Exceptions Issue

Hrm, it's interesting that Stroustrup writes "... it would be a mistake
to
assume that every exception derived from exception is a standard library
exception...", when elsewhere I believe that it is frowned upon. My
point
is, that user exceptions likely aren't derived from std::exception and
shouldn't be. It would be a big mistake for Boost.Threads to only
support
std::exceptions, especially since an already demonstrated implementation
does not preclude user defined types. (While it would be possible to
create
a throws_std_exceptions policy, it would probably be too limited for
inclusion in boost.)

Another Stroustrup quote :) "A library shouldn't unilaterally terminate
a
program. Instead, throw an exception and let a caller decide."

(I'd refer to Josuttis's book to see what you're talking about, but
since it
was a requirement in a course I co-designed, I found it to be one of the
most unreadable references available--I traded it in at a used
bookstore.)

----- Original Message -----
From: Victor A. Wagner, Jr.
Newsgroups: gmane.comp.lib.boost.devel
Sent: Tuesday, 2002:August:13 3:17 AM
Subject: Re: Re: Attempting resolution of Threads & Exceptions Issue

At Monday 2002/08/12 16:31, you wrote:
>----- Original Message -----
>From: "Eric Woodruff" <Eric.Woodruff_at_[hidden]>
> > [Un?]fortunatly, as far as I know, the end user is required to
specifiy
>the
> > exceptions they would like propagated.
>
>Are they?  If we agree to this, then the argument that others have made
>about library threads terminating is now a complete non-argument...
unless
>you expect to be able to specify the (theoretically) infinite number of
>exceptions that could occur.
>
>But I'm not sure this premise is true.  The easiest implementation
would be
>to convert all unhandled exceptions into a single thread_terminated
>exception during propogation (possibly being nice enough to duplicate
the
>what() results of std::exceptions).  Even if we go the extra mile of
>providing propogation of specified exception types as-is, we can still
>translate all other exception types as thread_terminated, or in this
case a
>better named unexpected_thread_termination.

I'd vote for (and help implement) a duplication of ALL of the
std::exceptions mentioned in Nicolai Josuttis's book (section 3.3.1) and
any others which may be in the standard (deriving from std::exception)
and
not mentioned in "The C++ Standard Library".

>Bill Kempf
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Victor A. Wagner Jr.      http://rudbek.com
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