Greg Colvin wrote: > std::exception used to have a why() member that returned the list of > exceptions leading to the one caught. Is that part of what you want?
Not exactly. I'm not too bothered about the history of the exceptions, I'm simply concerned with formatting useful error messages for users. In order to describe an error usefully/accurately you need as much context as possible, so such messages are most usefully described/formatted as the exception propogates. If you defer all message-formatting until some outer catch block you need to also leak sufficient implementation detail and knowledge to form that message. In the ideal library, such context information is only accumulated during exception propogation, and would not interfere with the exception handling system at all (no catch blocks, some sort of RAII/ScopeGuard-like object) To that extent, all that is really needed is a known stringstream per thread of execution, and some way to defer diagnostic generation unless an exiting the block due to exception propogation. To an extent, rather than missing why() I am looking for a replacement for what() as well!! Among other things I hear that can cause problems for localising error messages (something else this scheme should address) although I am lucky enough not to have to deal with such problems myself. -- AlisdairM _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
