----- Original Message ----- From: "Anthony Williams" <anthony.ajw@gmail.com> To: <boost-users@lists.boost.org> Sent: Thursday, July 17, 2008 11:21 AM Subject: Re: [Boost-users] [Boost.thread] Exception handling strategy ?
"Emil Dotchevski" <emil@revergestudios.com> writes:
Yes this should be easy, I'll do it after 1.36 ships.
Excellent!
If I understood, the MSVC-specific code allows the user to get the current exception without throwing the exception with boost::enable_current_exception(). What is the advantage if we can not profit of this mechanism with other compilers? A few months ago I proposed an intrusive way allowing the user to define which exceptions where wrapped by boost::exception_ptr. IMHO, the exception_ptr emulation (without language support) to transport exceptions between threads is not of real use if the user can not configurate the exceptions that can be thrown by 3pp as the Exception library do already for the STL exceptions. If the Exception library do not allow this, how can the Future library transport every exception between two threads? For recall, my proposal was the following: The exception library defines a macro such as: #define BOOST_EXCEPTION_CATCH_RETURN(EXCP) \ catch( EXCP & e ) { \ return exception_detail::current_exception_unknown_boost_exception(e); \ } The current_exception function has a USER_SLOT used us follows inline exception_ptr current_exception() { try { throw; } catch( exception_detail::cloning_base & e ) { exception_detail::clone_base const * c = e.clone(); BOOST_ASSERT(c!=0); return exception_ptr(c); } catch( std::invalid_argument & e ) { return exception_detail::current_exception_std_exception(e); } // ... as before #ifdef BOOST_EXCEPTION_USER_SLOT #include BOOST_EXCEPTION_USER_SLOT #endif catch( ... ) { return exception_detail::current_exception_unknown_exception(); } } The user can define BOOST_EXCEPTION_USER_SLOT to a file containing one line for each exception that must be transported: BOOST_EXCEPTION_CATCH_RETURN(3pp::exception1) BOOST_EXCEPTION_CATCH_RETURN(boost:lock_error) Of course this has a limitation: it works only if the function using the current_exception is also inlined. Best, Vicente