coding style - Make multiple asynchronous calls and do something when they are completed -

I have participated in this problem in many problematic languages ​​and I was just wondering what its best way is.

I have three method calls that are closed asynchronously. I have a callback, I want to do something when all three callbacks will be completed.

What is the best way to code this? I usually end up with all these public bool flags and as you call more the code becomes more complex.

After

Coming from C #, I would probably use it to create an array of objects ( To complete each task), and pass that array to WaitAll . Threaded tasks will get each manual resetset object, and call the set method when they are ready. Waiting will stop all calling thread until all the tasks are completed. I will give a C # code example: Private Zero SpawnWorkers () {ManualResetEvent [] [ResetEvents = New [] {New ManualResetEvent (wrong), New ManualResetEvent (wrong)}; //, do not block workers from a separate thread so that // WaitAll calls the main thread ThreadPool.QueueUserWorkItem ((state) =>; {ThreadPool.QueueUserWorkItem (Worker1, resetEvents [0]); ThreadPool.QueueUserWorkItem (Worker2, resetEvents [1]; WaitHandle.WaitAll (resetEvents); this.BeginInvoke (AllTasksAreDone);}); } Private Zero AllTasksAreDone () {// OK, all is done, according to the Private Zero Worker1 (object state)}} {// work, and then wait thread ((ManualResetEvent state)) .set ( ); } Private zero worker 2 (object state) {// work, and then waiting thread (signaling to state (manual reset) state) .set (); }

Note that AllTasksAreDone method will not execute on thread thread thread that was used to give workers eggs, and on main thread ... It seems that many other languages ​​have similar structures.