is there way to check if performSelector:withObject:afterDelay: has been registered?

I whould like to know if there is a way to determine if performSelector:withObject:afterDelay: for the given object has been called (registered to be called). (I could use cancelPreviousPerformRequestsWit开发者_如何学编程hTarget:selector:object: and re-call performSelector:withObject:afterDelay:, ok but I'm interested to know if there is the alternative).

Thanks

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The best thing to do would be to make sure that the selector being called can be called multiple times safely.

For example, use a flag in the target object to track if the method has already been invoked e.g.

-targetSelector: (id) param
{
    if (!hasBeenRun) // hasBeenRun is a boolean intance variable
    {
        hasBeenRun = true;
        // other stuff
    }
}