Passing handle to another function

[Nucleus]

In a project add 2 command buttons.

Add this code:

Option Explicit
Private Declare Function MoveWindow Lib "user32" (ByVal hwnd As Long, ByVal x As Long, ByVal y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal bRepaint As Long) As Long
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function GetWindowRect Lib "user32" (ByVal hwnd As Long, lpRect As RECT) As Long
 
Private Type RECT
        Left As Long
        Top As Long
        Right As Long
        Bottom As Long
End Type
 
 
Private Sub Command1_Click()
Shell "C:\winnt\system32\calc.exe", vbNormalFocus
End Sub
 
 
Private Sub Command2_Click()
Dim hwnd&, width&, height&
Dim R As RECT
 
hwnd = FindWindow("scicalc", vbNullString)
GetWindowRect hwnd, R
width = R.Right - R.Left
height = R.Bottom - R.Top
'center on screen
MoveWindow hwnd, Screen.width / Screen.TwipsPerPixelX / 2 - width / 2, Screen.height / Screen.TwipsPerPixelY / 2 - height / 2, width, height, 1
 
End Sub

Now click the first command button to launch windows calculator, click the next button to position in the center of the screen.