On Sat, Jun 23, 2012 at 10:40 PM, Robert Ramey <ramey@rrsd.com> wrote:
If this is invoked at the exception site it works. If it is invoked anywhere else - like a rethrow it doesn't. It's totally non-intuitive and a trap for users. There is no mention of this in the documentation.
The danger of slicing in C++ is beyond the scope of any Boost library documentation. That said, Boost Exception does protect the user from slicing boost::exception objects.
And I believe that a solution could have been crafted to avoid the issues that I've raised but that Emil doesn't agree that these concerns are legimate. I know steve doesn't agree with me on this either.
The concerns are legitimate, the disagreement is over the conclusion you've reached. You're yet to back your beliefs with facts.
So now I would have to provide a counter example which means basically re-doing the original work in the right way as I see it.
A lot of time got wasted in this discussion explaining why your ideas don't work. Producing a working piece of code would be a welcome change, I think.
I may be misunderstanding, but IIUC, the "problem" that he "fixed" was that his change caused already-unsupported misuses of boost::throw_exception to stop compiling. It's arguable that those misuses *should* be flagged with compiler errors.
the original boost::throw_exception was defined as:
#ifdef BOOST_NO_EXCEPTIONS void throw_exception( std::exception const & e ); // user defined #else template<class E> void throw_exception(E const & e){ throw(e); } #endif
it's hard to see how one could even define "misuse" of this - much less detect it.
You should try to see it though. Several people have pointed it out. Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode