Boost logo

Boost :

From: Beman Dawes (bdawes_at_[hidden])
Date: 2002-10-12 08:01:13

At 03:05 AM 10/12/2002, Ross Smith wrote:
>On Saturday, 12 October 2002 18:28, Joel de Guzman wrote:
>> From: "Carl Daniel" <cpdaniel_at_[hidden]>
>> > Exception classes thrown by Spirit (parser_error<>,
>> > illegal_backtracking) don't derive from std::exception - shouldn't
>> > they?
>> I'm not sure. Should it? What will be the benefits in doing so?
>> The truth is, I'm not quite happy with the standard C++ exceptions.
>> For one, it's hard coded the what() to be a string.
>The big advantage of requiring all exceptions to be derived from
>std::exception, as I see it, is that you can write your main function
>like this...
> int main() {
> try {
> // code goes here
> return 0;
> }
> catch (const std::exception& ex) {
> std::cerr << "*** " << ex.what() << "\n";
> return EXIT_FAILURE;
> }
> }
>...and be confident of getting an error message instead of a crash if
>anything gets thrown that you haven't explicitly caught.

Yes, and that idiom is so useful that Boost.Test provides library code to
handle the details.

> You can do the
>same thing in other functions that you don't want anything to escape
>from (e.g. destructors, extern "C" functions that will be used as
>callbacks, etc). If you can't rely on everything having std::exception
>in its family tree, you have to either use catch (...), which denies
>you the chance of logging any meaningful error message, or write a
>whole stack of catch clauses for every exception you can think of.
>I'd like to suggest (to the Boost readership in general) that this
>should be made a requirement for all Boost libraries.

I agree, unless there is some application specific reason why another
approach is better.


Boost list run by bdawes at, gregod at, cpdaniel at, john at