On 12/12/05, Christopher Kohlhoff <chris@kohlhoff.com> wrote:
Hi Felipe,
--- Felipe Magno de Almeida <felipe.m.almeida@gmail.com> wrote: <snip>
[snip]
This could be done by composing a new function object to be passed as the handler, e.g.:
async_read(s, buffers, combine_handlers(handler1, handler2));
Boost.Lambda may also be of some use here.
However I am not convinced that this approach would be widely applicable. There are many cases in networking where an error for an individual operation is not an error for the application.
What I mean is to be able to have like two member functions in a class, one for handling an error in the read operation, and other for handling the correct case.
I also see the current "exactly-once" semantics of invoking handlers as important in aiding correct program design, so I'd be wary of using anything that changed that.
Didnt understood what you meant... You think every functor should be executed exactly-once for correct program design? Wouldnt this still be safe? class handler { void fail(asio::error err) { // handle the error case, and probably delete this handle, or reuse it for retrying } void success(int size) { // do something, or continue reading or delete this } // member variables public: handler() { async_read(s, buffers, combine_handlers( boost::bind(boost::mem_fn(&handler::success), this) , boost::bind(boost::mem_fn(&handler::fail), this) )); } };
Cheers, Chris
Thanks, -- Felipe Magno de Almeida