Well I already gave you the link to the documentations of two APIs. The usage of GetProcessHandleCount is trivial, documentation says everything you need. For NtQuerySystemInformation you can check out this[^] thread, where you will find a sample code that actually retrieves Handle Count, Thread Count, etc. The example code actually uses ZwQuerySystemInformation[^] function but in fact this does not change anything for you, the usage is exactly the same. P.S. If you actually want to know the difference between 'Nt' and "Zw' prefixed native API functions, have a look at this interesting article[^]. :)