IsIconic() behavior varies depending on the environment - vb.net

Question

I'd like to use IsIconic function to check whether the specified window is minimized (iconic).
IsIconic function
https://msdn.microsoft.com/ja-jp/library/windows/desktop/ms633527(v=vs.85).aspx
My code works properly in certain environments, but it does not work in other environments.
Imports System.Runtime.InteropServices
Public Class Form1
<DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Public Shared Function IsIconic(ByVal hWnd As IntPtr) As Long
End Function
<DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function FindWindow(ByVal lpClassName As String, ByVal lpWindowName As String) As IntPtr
End Function
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim hWnd As IntPtr = FindWindow(Nothing, "Google - Google Chrome")
If CBool(IsIconic(hWnd)) Then
Debug.WriteLine("Chrome is iconic.")
Else
Debug.WriteLine("Chrome is not iconic.")
End If
End Sub
End Class
When I run it with 64 bit Windows 7 OS, I can determine correctly whether Chrome is iconified.
However, when running on 32 bit Windows 7 OS, "Chrome is iconic." is always displayed in the immediate window regardless of whether or not Chrome is actually iconified.
Could you tell me why this difference occurs?
Is this phenomenon caused by the difference in OS bit number? Or something else?

Answer 1

Your return type of the IsIconic() function is wrong.
This:
Public Shared Function IsIconic(ByVal hWnd As IntPtr) As Long
...should be this:
Public Shared Function IsIconic(ByVal hWnd As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
This also means that you can (and should) change:
If CBool(IsIconic(hWnd)) Then
Debug.WriteLine("Chrome is iconic.")
Else
...
to:
If IsIconic(hWnd) Then
Debug.WriteLine("Chrome is iconic.")
Else
...