APIGdiConstants.au3 vs. Microsoft Docs Discrepancy

[Decibel]

This isn't a big deal to me, but I noticed this and am curious how APIGdiConstants.au3 could still work when the MS docs show a different enum value.

I'm running AutoIt 3.3.16.1 on Win11 x64.

APIGdiConstants.au3 has the following lines (75-87) that sets the first enum $DWMWA_NCRENDERING_ENABLED = 1:

; _WinAPI_DwmGetWindowAttribute(), _WinAPI_DwmSetWindowAttribute()
Global Const $DWMWA_NCRENDERING_ENABLED = 1
Global Const $DWMWA_NCRENDERING_POLICY = 2
Global Const $DWMWA_TRANSITIONS_FORCEDISABLED = 3
Global Const $DWMWA_ALLOW_NCPAINT = 4
Global Const $DWMWA_CAPTION_BUTTON_BOUNDS = 5
Global Const $DWMWA_NONCLIENT_RTL_LAYOUT = 6
Global Const $DWMWA_FORCE_ICONIC_REPRESENTATION = 7
Global Const $DWMWA_FLIP3D_POLICY = 8
Global Const $DWMWA_EXTENDED_FRAME_BOUNDS = 9
Global Const $DWMWA_HAS_ICONIC_BITMAP = 10
Global Const $DWMWA_DISALLOW_PEEK = 11
Global Const $DWMWA_EXCLUDED_FROM_PEEK = 12

Microsoft (dated 07/10/2023) has the following Syntax that I assume is starting at zero, setting DWMWA_NCRENDERING_ENABLED = 0

typedef enum DWMWINDOWATTRIBUTE {
  DWMWA_NCRENDERING_ENABLED,
  DWMWA_NCRENDERING_POLICY,
  DWMWA_TRANSITIONS_FORCEDISABLED,
  DWMWA_ALLOW_NCPAINT,
  DWMWA_CAPTION_BUTTON_BOUNDS,
  DWMWA_NONCLIENT_RTL_LAYOUT,
  DWMWA_FORCE_ICONIC_REPRESENTATION,
  DWMWA_FLIP3D_POLICY,
  DWMWA_EXTENDED_FRAME_BOUNDS,
  DWMWA_HAS_ICONIC_BITMAP,
  DWMWA_DISALLOW_PEEK,
  DWMWA_EXCLUDED_FROM_PEEK,
  DWMWA_CLOAK,
  DWMWA_CLOAKED,
  DWMWA_FREEZE_REPRESENTATION,
  DWMWA_PASSIVE_UPDATE_MODE,
  DWMWA_USE_HOSTBACKDROPBRUSH,
  DWMWA_USE_IMMERSIVE_DARK_MODE = 20,
  DWMWA_WINDOW_CORNER_PREFERENCE = 33,
  DWMWA_BORDER_COLOR,
  DWMWA_CAPTION_COLOR,
  DWMWA_TEXT_COLOR,
  DWMWA_VISIBLE_FRAME_BORDER_THICKNESS,
  DWMWA_SYSTEMBACKDROP_TYPE,
  DWMWA_LAST
} ;

What really throws me is that the APIGdiConstants.au3 lines just below the set above (89-91) do correlate to what Microsoft says and they work as expected:

Global Const $DWMNCRP_USEWINDOWSTYLE = 0
Global Const $DWMNCRP_DISABLED = 1
Global Const $DWMNCRP_ENABLED = 2

Microsoft (dated 02/22/2024):

typedef enum DWMNCRENDERINGPOLICY {
  DWMNCRP_USEWINDOWSTYLE,
  DWMNCRP_DISABLED,
  DWMNCRP_ENABLED,
  DWMNCRP_LAST
} ;

AutoIt Code Example:

Opt("MustDeclareVars", 1);require variables to be declared

#include <GUIConstantsEx.au3>
#include <WinAPIGdi.au3>

;*** Create a GUI with various controls.
Local $hGUI = GUICreate("Example", 400, 400)

;*** Display the GUI.
GUISetState(@SW_SHOW, $hGUI)

ConsoleWrite("$DWMWA_NCRENDERING_POLICY: '" & $DWMWA_NCRENDERING_POLICY & "' (expecting 2, but MS says 1)" & @CRLF)
ConsoleWrite("$DWMNCRP_DISABLED: '" & $DWMNCRP_DISABLED & "' (expecting 1 per AutoIt and MS)" & @CRLF)

#Region - Uncomment the block for the scenario that you want to see

    ;*** Demonstrate that APIGdiConstants.au3 declaration of $DWMWA_NCRENDERING_POLICY = 2 instead of Microsoft's enum = 1 works
    ConsoleWrite("Before: '" & _WinAPI_DwmGetWindowAttribute ( $hGUI, $DWMWA_NCRENDERING_ENABLED ) & "' (expecting 1)" & @CRLF)
    _WinAPI_DwmSetWindowAttribute($hGUI, $DWMWA_NCRENDERING_POLICY, $DWMNCRP_DISABLED)
    ConsoleWrite("After:  '" & _WinAPI_DwmGetWindowAttribute ( $hGUI, $DWMWA_NCRENDERING_ENABLED ) & "' (expecting 0)" & @CRLF)

;~  ;*** Demonstrate that the value for APIGdiConstants.au3 declaration of $DWMWA_NCRENDERING_POLICY = 2 instead of Microsoft's enum = 1 works
;~  ConsoleWrite("Before: '" & _WinAPI_DwmGetWindowAttribute ( $hGUI, $DWMWA_NCRENDERING_ENABLED ) & "' (expecting 1)" & @CRLF)
;~  _WinAPI_DwmSetWindowAttribute($hGUI, 2, $DWMNCRP_DISABLED)
;~  ConsoleWrite("After:  '" & _WinAPI_DwmGetWindowAttribute ( $hGUI, $DWMWA_NCRENDERING_ENABLED ) & "' (expecting 0)" & @CRLF)

;~  ;*** Demonstrate that Microsoft's enum = 1 does not work because APIGdiConstants.au3 has it mapped to $DWMWA_NCRENDERING_ENABLED
;~  ConsoleWrite("Before: '" & _WinAPI_DwmGetWindowAttribute ( $hGUI, $DWMWA_NCRENDERING_ENABLED ) & "' (expecting 1)" & @CRLF)
;~  _WinAPI_DwmSetWindowAttribute($hGUI, 1, $DWMNCRP_DISABLED)
;~  ConsoleWrite("After:  '" & _WinAPI_DwmGetWindowAttribute ( $hGUI, $DWMWA_NCRENDERING_ENABLED ) & "' (expecting 0)" & @CRLF)

#EndRegion - Uncomment the block for the scenario that you want to see

;*** Delete the previous GUI and all controls.
GUIDelete($hGUI)

Here is my online C++ attempt to understand/confirm how C++ enumerations work, and they seem to work exactly how I understand (I.e. start at 0 unless differently declared).

Edit: This stemmed from an example about how to force rounded corners, of which I actually wanted the opposite, and achieved it from that code.

Edited October 30, 2024 by Decibel