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

From: Eric Woodruff (Eric.Woodruff_at_[hidden])
Date: 2002-08-13 08:24:12

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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