Hi, I've already replied in an earlier private email conversation, but for the benefit of the list...

I'm trying to use boost::asio, and I find that there isn't a built-in timeout parameter in any async operation. I think it's a very important function when writing real life programs, and I have done some walk around work, how can I try to contribute?

There isn't a way to implement timeouts on the individual async operations both efficiently and portably. E.g. the async I/O functions on windows (like AcceptEx etc) don't support timeouts. Instead, the intended approach is to use a deadline_timer object and start a timer when you start the operation. The examples under example/timeouts illustrate this. In my experience timeouts can often apply at a coarser granularity than the socket's send and receive operations. For example you might develop a high level function that receives a complex message (such as an HTTP reply) and want to set a timeout for receiving the entire message. However the implementation of this high level read function wouldn't need to be aware that a deadline_timer is being used. Cheers, Chris