Oliver.Kowalke@qimonda.com wrote:
throw my_exception() << throw_info<tag_errno>(errno) << throw_info<tag_function>(BOOST_CURRENT_FUNCTION);
<snip>
Any strong preferences?
What about upcoming boost::system::error_code and boost::system::system_error (used to report os errors)?
My example (above) was derived from http://www.revergestudios.com/boost-exception/boost-exception.htm#basic_usag..., and it was only intended to visualize what that example would look like if exception_info is renamed to throw_info due to the name clash with the exception_info macro defined in windows.h (but see Minh's responce in which he proposes the name error_info, which I think is what I'm going with now.) If I read you correctly, what you're saying is that if boost::exception is accepted, we need to think about integration with the rest of boost. For example, if boost::system::system_error derives from std::runtime_error (as it does now) and also from boost::exception, (someone correct me if I'm missing something) the definition of boost::system_error could be reduced to: struct tag_system_error_code: exception_info_value<error_code> { }; struct tag_sytem_error_msg: exception_info_value<std::string> { }; struct tag_system_error_action: exception_info_value<message_action> { }; struct tag_system_error_category: exception_info_value<error_category> { }; class system_error: public std::runtime_error, public boost::exception { public: char const * what() const throw() //resolve ambiguity. { return boost::exception::what(); } }; Then, when throwing, we can write: throw system_error() << exception_info<tag_system_error_code>(ec) << exception_info<tag_system_error_msg>(msg) << ... ; depending on what information is available to us. This also allows contexts that are higher in the call stack to catch( boost::exception & ), encode additional information available to them and rethrow. The rationale for this is discussed here: http://www.revergestudios.com/boost-exception/boost-exception.htm#Q_why_both.... It is also possible to keep the current definition of class system_error, and simply change throw statements to: throw enable_exception_info(system_error(....)); This also enables contexts that are higher in the call stack to catch( boost::exception & ), add more values and rethrow, without interfering with code unaware of boost::exception. --Emil Dotchevski