When processing a range loop (threaded function has min and max parameters) it is the users responsability to update Thread.LoopIndex variable, if this indicator is required. Example: 

IntInterlockedIncrement(Thread.LoopIndex); 

This is because the actual loop runs within the users code. This function will return the sum of iterations added to the starting Min value. 

In case of a while-loop, the CombinedLoopIndex and CombinedLoopCount returns the same result. The user is not allowed to increase Thread.LoopIndex 

In case of a for-loop without specified range the function will return the sum of iterations added to the starting Min value. The user is not allowed to increase Thread.LoopIndex

public