CheckAdapters is procedure used to implement monitoring of IPAddresses assigned in the local system, and status notifications using the OnStatusChanged event handler. 

CheckAdapters uses the Busy property to determine if the method can be synchronously executed in the Thread, or must wait for completion of a prior call to the Check Adapters method. CheckAdapters is assigned to the OnTimerEvent for the Thread used in the component. 

CheckAdapters gets the current IPAddresses for the component, and compares the current IPAddresses to the previous values in the property. When a change is detected (an IP address has been added, deleted, or modified), the OnStatusChanged event handler is signalled using the adapter index and the IP address information. 

CheckAdapters sets Busy to False on completion of the method.

Active IPAddresses OnStatusChanged Busy Thread TIdIPAddrMonThread.OnTimerEvent