C# Async.

How a C# program waits: tasks, awaiting, cancellation, and the failures each shape produces. Covers 10 topics.

• C# Async · 1 of 3

  Tasks

  Which three TaskStatus values mark a finished C# task?

  AWaitingToRun, Running, RanToCompletionBCreated, WaitingToRun, CanceledCRanToCompletion, Faulted, CanceledDWaitingToRun, Running, Canceled

• C# Async · 2 of 3

  Coordination

  In C#, why does the compiler forbid await inside a lock body?

  Athe lock would be released twice overBthe code can resume on another threadCthe await would never complete at allDthe body would run more than one time over

• C# Async · 3 of 3

  Deadlocks

  In this C# program, the outer thread has lock a while a task inside lock (b) calls Monitor.TryEnter(a, 200). What does TryEnter return?

  var a = new object(); var b = new object();bool tookBoth = false;lock (a){    var other = Task.Run(() => { lock (b) { return Monitor.TryEnter(a, 200); } });    tookBoth = other.Result;}Console.WriteLine($"{tookBoth} done");

  ATrue, the task runs on another threadBIt blocks until the outer lock exitsCFalse, the outer thread still owns aDTrue, since the task already owns b