Stopping timer in its callback method
c#, callback, reentrancy, timer
Solution
You could let the timer continue firing the callback method but wrap your non-reentrant code in a Monitor.TryEnter/Exit. No need to stop/restart the timer in that case; overlapping calls will not acquire the lock and return immediately.
private void CreatorLoop(object state)
{
if (Monitor.TryEnter(lockObject))
{
try
{
// Work here
}
finally
{
Monitor.Exit(lockObject);
}
}
}
Problem
I have a System.Threading.Timer that calls its appropriate event handler (callback) every 10 ms. The method itself is not reentrant and can sometimes take way longer than 10 ms. Thus, I want to stop the timer during method execution. Code: ``` private Timer _creatorTimer; // BackgroundWorker's work private void CreatorWork(object sender, DoWorkEventArgs e) { _creatorTimer = new Timer(CreatorLoop, null, 0, 10); // some other code that worker is doing while the timer is active // ... // ... } private void CreatorLoop(object state) { // Stop timer (prevent reentering) _creatorTimer.Change(Timeout.Infinite, 0); /* ... Work here */ // Reenable timer _creatorTimer.Change(10, 0); } ``` MSDN states that the callback method is called (every time the timer fires) in separate thread from the thread pool. That means that if I stop the timer the first thing in method it still doesn't neccessarily prevent the timer to fire and run another instance of the method before the first one had a chance to stop the timer. Should maybe the timer (or even the non-reentrant method itself) be locked? What is the right way to prevent timer from firing during execution of its callback (and non-reentrant) method?