Have a look at SendInput for an example of where these constants are used.

C# Definition:

public class Win32Consts
{
   // For use with the INPUT struct, see SendInput for an example
   public const int INPUT_MOUSE     = 0;
   public const int INPUT_KEYBOARD  = 1;
   public const int INPUT_HARDWARE  = 2;
}    

VB Definition:

Public Enum Win32Consts As Integer

    ' For use with the INPUT struct, see SendInput for an example
    INPUT_MOUSE = 0
    INPUT_KEYBOARD = 1
    INPUT_HARDWARE = 2

End Enum

User-Defined Field Types:

None.

Notes:

None.