Extern Object - Using DLL Functions in QTP

'###############################################
'           Extern Object 
'###############################################

' Purpose - Declares references to external procedures which are stored with a dynamic-link library (DLL). 

'Syntax:-  Extern.Declare(RetType, MethodName, LibName, Alias [, ArgType(s)]) 

'Ex:- 
'  FindWindowA is a function in user32.dll. This function is used to find a window which is currently opened on Desktop.
'  This function takes two string inputs NativeClass & Title of the Window.
'  This will return a handler value of the identified window.
'  If it is returned 0 then there is no window found

 'Declare FindWindow method 
 Extern.Declare micHwnd, "FindWindow", "user32.dll", "FindWindowA", micString, micString 
 
 'Get HWND of the Notepad window 
 hwnd = Extern.FindWindow("Notepad", vbNullString) 
 
 If hwnd = 0 Then 
   MsgBox "Notepad window not found" 
  Else
   MsgBox "Notepad window found" 
 end if