How can I call Get/SetPriorityClass and Get/SetThreadPriority?

At issue is the HANDLE parameter. I had hoped that I might get away
with passing a NULL pointer (ByVal 0), but it didn't work.

Public Declare Function GetPriorityClass Lib "kernel32" (ByRef pHandle
As Long) As Long
Public Declare Function GetThreadPriority Lib "kernel32" (ByRef
tHandle As Long) As Long

Private Sub getProcInfo()
Dim x As Long
x = GetPriorityClass(ByVal 0)
Debug.Print "GetPriorityClass= "; Hex(x)
x = GetThreadPriority(ByVal 0)
Debug.Print "GetThreadPriority= "; Hex(x)
End Sub