Non blocking locking

Question

I want to start some new threads each for one repeating operation. But when such an operation is already in progress, I want to discard the current task. In my scenario I ne

Answer 1

You should use Interlocked class atomic operations - for best performance - since you won't actually use system-level sychronizations(any "standard" primitive needs it, and involve system call overhead). //simple non-reentrant mutex without ownership, easy to remake to support //these features(just set owner after acquiring lock(compare Thread reference with Thread.CurrentThread for example), and check for matching identity, add counter for reentrancy) //can't use bool because it's not supported by CompareExchange private int lock;

public bool TryLock()
{
  //if (Interlocked.Increment(ref _inUseCount) == 1)      
  //that kind of code is buggy - since counter can change between increment return and
  //condition check - increment is atomic, this if - isn't.       
  //Use CompareExchange instead
  //checks if 0 then changes to 1 atomically, returns original value
  //return true if thread succesfully occupied lock
  return CompareExchange(ref lock, 1, 0)==0;
  return false;

}
public bool Release()
{
  //returns true if lock was occupied; false if it was free already
  return CompareExchange(ref lock, 0, 1)==1;
}