Option Explicit On
Option Strict On

Imports System.Runtime.InteropServices

Module Module1

    Public Declare Function SystemParametersInfo Lib "USER32" Alias "SystemParametersInfoW" _
       (ByVal uiAction As UInteger, _
        ByVal uiParam As UInteger, _
        ByRef pvParam As UInteger, _
        ByVal fWinIni As UInteger) As <MarshalAs(UnmanagedType.Bool)> Boolean

    Public Declare Function SystemParametersInfo Lib "USER32" Alias "SystemParametersInfoW" _
       (ByVal uiAction As UInteger, _
        ByVal uiParam As UInteger, _
        ByVal pvParam As IntPtr, _
        ByVal fWinIni As UInteger) As <MarshalAs(UnmanagedType.Bool)> Boolean

    Public Const SPI_GETFOREGROUNDLOCKTIMEOUT As UInteger = &H2000
    Public Const SPI_SETFOREGROUNDLOCKTIMEOUT As UInteger = &H2001

    Sub Main()
        Dim oldValue As UInteger = 2345UI   'dummy value
        SystemParametersInfo(SPI_GETFOREGROUNDLOCKTIMEOUT, 0UI, oldValue, 0UI)  '☆A
        Console.WriteLine(oldValue)

        'Dim value32 As Integer = 3456I  'dummy value
        'Dim p1 As IntPtr = Marshal.AllocHGlobal(IntPtr.Size)
        'Marshal.WriteInt32(p1, value32)
        'SystemParametersInfo(SPI_GETFOREGROUNDLOCKTIMEOUT, 0UI, p1, 0UI)  '☆B
        'value32 = Marshal.ReadInt32(p1)
        'Marshal.FreeHGlobal(p1)
        'Console.WriteLine(oldValue)

        'SystemParametersInfo(SPI_SETFOREGROUNDLOCKTIMEOUT, 0UI, New IntPtr(20002), 1UI)   '★C
        'SystemParametersInfo(SPI_SETFOREGROUNDLOCKTIMEOUT, 0UI, New IntPtr(&H3579B), 0UI) '★D
    End Sub

End Module