[boost] [Asio] How do i code a resource clean server shutdown?

From: Rod Morison (rod_at_[hidden])
Date: 2006-08-17 19:41:12

I'm studying the async daytime server example, Daytime.3 (0.3.7  
flavor):  
http://asio.sourceforge.net/boost_asio_0_3_7/libs/asio/doc/tutorial/tutdaytime3src.html
(I'm doing an Asio proof/concept for an app that has to dynamically  
change it's service ports.)

I'm trying to think through how to perform a clean shutdown in this  
example. There could be a number of pending async_write()'s, each with  
their own socket and uncalled handler. There is probably also a socket  
waiting on the async_accept() with an an uncalled handler.

Questions:

- With the work pending, io_service will need to call it's interrupt()  
function (from another thread) to stop processing, correct?

- If io_service is destroyed, what happens to the otherwise pending  
work, i.e., the async_write's and async_accepts that it controls? What  
about the socket resources?

- I can close the tcp::acceptor in tcp_server, but what about the  
socket that's listening on it?

- If Asio doesn't release system handles, e.g., sockets, how do I get  
at the resources to clean up?

- Is there an example of a resource clean shutdown? I skimmed the  
example apps and didn't see one first pass.

Thanks,

Rod

-
If the io_service is destroyed, what

Is there a way to do this with the io_service?

In a watchdog thread...
-call io_service.interrupt() to stop processing
-tell the tcp_server to

The io_service.run() won't exit until all services and handlers are  
finished. Let me take a stab at a shutdown design and perhaps Asio  
vets would be willing to tear it apart/fix it?

This assumes the Daytime.3 server code at  
http://asio.sourceforge.net/boost_asio_0_3_7/libs/asio/doc/tutorial/tutdaytime3src.html
(I noticed the 0.3.6 example is somewhat different.)

in tcp_server
-------------

- add a cleanup() method that calls acceptor_.close()

in main()
---------
- add a watchdog thread that will shutdown the server's io_service
- if shutdown time then

How do I notify handlers
io_service.dispatch() or io_service.post() to wake up handlers