Chapter 7, lesson 3: Asynchronous Programming Model (APM).

• APM - allowing some portions of code to run on separate threadds.
• Many classes support APM - supply BeginXXX and EndXXX. e.g. FileStreamBeginRead(), EndRead(). Allows asynch. execution of mthds.
• EndXXX() - calling this blocks until asynch work is complete.
• Rendevous Models - informs when to call EndXXX(). 3 models - Wait-Until-Done, polling, callback.
• wait-until-done:
• 1) strm.BeginRead(buffer,0,buffer.Length,null,null); - null for last 2 args as not Callback.
• polling:
• 1) while (!result.IsCompleted){//do work here Thread.Sleep(100);}
• callback model:
• 1) Create new AsyncCallback delegate (on another thread) when operation is complete - strmBeginRead(buffer,o,buffer.Length,new AsyncCallback(CompleteRead),strm);
• ThreadPool - built-in, and can be used in many situations where might expect to to create own threads.
• 1) WaitCallback workItem = new WaitCallback(WorkWithParameter);
• 2) ThreadPool.QueueUserWorkItem()
• ThreadPool - faster - threads reused + saves expensive setup costs. As threads become available, the thread pool posts new work to the thread.
• change threa pool thread limits - 1) thread starvation, 2) startup thread speed.
•