Compile error: The code in this project must be updated for use on 64-bit systems.

' API declarations:
Private Declare Function apiGetClientRect Lib "user32" Alias "GetClientRect" (ByVal hwnd As Long, lpRect As typRect) As Long
Private Declare Function apiGetWindowRect Lib "user32" Alias "GetWindowRect" (ByVal hwnd As Long, lpRect As typRect) As Long
Private Declare Function apiSetWindowPos Lib "user32" Alias "SetWindowPos" (ByVal hwnd As Long, ByVal hWndInsertAfter As Long, ByVal x As Long, ByVal y As Long, ByVal cx As Long, ByVal cy As Long, ByVal wFlags As Long) As Long
Private Declare Function apiShowWindow Lib "user32" Alias "ShowWindow" (ByVal hwnd As Long, ByVal nCmdShow As Long) As Long
' Type declarations:
Private Type typRect
    Left As Long
    Top As Long
    Right As Long
    Bottom As Long
End Type
' Constant declarations:
Private Const SW_RESTORE = 9
Private Const SWP_NOSIZE = &H1 ' Don't alter the size
Private Const SWP_NOZORDER = &H4 ' Don't change the Z-order
Private Const SWP_SHOWWINDOW = &H40 ' Display the window
' **************************************
' * Center a form in the Access window *
' **************************************
' Created 1-22-2002 by Peter M. Schroeder
Public Function gfncCenterForm(parForm As Form) As Boolean
    Dim varAccess As typRect, varForm As typRect
    Dim varX As Long, varY As Long
    
    On Error GoTo CenterForm_Error
    Call apiGetClientRect(hWndAccessApp, varAccess) ' Get the Access client area coordinate
    Call apiGetWindowRect(parForm.Hwnd, varForm) ' Get the form window coordinates
    varX = CLng((varAccess.Left + varAccess.Right) / 2) - CLng((varForm.Right - varForm.Left) / 2) ' Calculate a new left for the form
    varY = CLng((varAccess.Top + varAccess.Bottom) / 2) - CLng((varForm.Bottom - varForm.Top) / 2) ' Calculate a new top for the form
    varY = varY - 45 ' Adjust top for true center
    varY = varY - 20 ' Adjust top for appearance
    Call apiShowWindow(parForm.Hwnd, SW_RESTORE) ' Restore form window
    Call apiSetWindowPos(parForm.Hwnd, 0, varX, varY, (varForm.Right - varForm.Left), (varForm.Bottom - varForm.Top), SWP_NOZORDER Or SWP_SHOWWINDOW Or SWP_NOSIZE) ' Set new form coordinates
    gfncCenterForm = True
    Exit Function
    
CenterForm_Error:
    gfncCenterForm = False
End Function

    Private Declare Function apiGetClientRect Lib "user32" Alias "GetClientRect" (ByVal hwnd As Long, lpRect As typRect) As Long

#If Win64 Then
    Private Declare PtrSafe Function apiGetClientRect Lib "user32" Alias "GetClientRect" (ByVal hwnd As LongLong, lpRect As typRect) As LongLong
#Else
    Private Declare Function apiGetClientRect Lib "user32" Alias "GetClientRect" (ByVal hwnd As Long, lpRect As typRect) As Long
#End If