Re: [Boost-users] [asio]How to insure async handles not be called after calling deadline_timer::cancel()?

Does this mean that async handlers may be called after calling deadline_timer::cancel()

Yes.

If yes, it seems make things unintuitive,  eg. delete the resources that associate with  handlers after cancel().

Don't delete these resources, bind them to a shared_ptr and they will be released automatically after the handler invocation is complete.