1 Methods of handling WMConnectionDidDieNotification notification events
2 (same for WMConnectionDidTimeoutNotification)
3 ----------------------------------------------------------------------
5 Once your program got this notification (you need to install an observer for
6 it), there are some ways to handle it:
8 1. Make your observer enqueue a new notification in the ASAP queue, and the
9 observer for this new notification (it can be the same function if you
10 arrange to distinguish between the two cases), should remove the connection.
11 You can also close the connection before enqueuing the new notification to
12 the ASAP queue, but is not strictly necessarily, since it will be closed
13 when the observer for the new enqueued notification will be called and you
14 will call the close/remove function there. This is just to make sure your
15 connection will be silent, and won't generate new events until you reach
17 This is by far the best method, since it will assure you that if you
18 enqueue more than one notification to remove the same connection, they will
19 be coalesced, and called only once.
20 2. In your observer, put the died/closed connection in a bag, and destroy all
21 the connections present in the bag, in your main loop, after you call the
22 WHandleEvents()/WMHandleEvent(). Also closing the connection can be done
23 before putting the connection in the bag, but is optional as noted above.
24 In this case you need to make sure you don't put in the bag the same
25 connection more than once, in case the DieNotification is sent more that
26 once to you. This is automagically solved by method 1.
27 3. In case it's your only connection, and you plan to exit if it was closed or
28 died, then you can safely close/remove it, and exit. As long as you no
29 longer access it, there is no problem.
31 4. Make you observer remove the connection. Then make sure that after that
32 point your code no longer tries to access that connection (this usually
33 means until your code gets back to the main loop). This is almost always
34 very hard to achive and subject to hidden errors. I do not recommend this
35 way of handling the died notification. It is ugly and very complicated to
36 handle. If you use it and get plenty of SIGSEGVs then you know why.
37 This method was not presented here to be used, but to show what should
38 be avoided in dealing with the died notification, in case someone gets the
39 idea to try it this way.
42 Note: read/write operations means to use our read/write functions (like
43 WMGetMessage()/WMSendMessage()), not the C library ones read()/write().
44 Note2: removing a connection is done by WMDestroyConnection(), while
45 WMCloseConnection() only closes the socket, and removed any pending
46 queues and timers on the connection.