GdipGetLineColors has different call signatures for 32-bit versus 64-bit

[GCuser99]

I've confirmed that the 32- and 64-bit versions have different call signatures by using both in tB (and of course they are not interchangeable). The 32-bit version requires a Long array of dimension 2 (Colors(0) and Colors(1)).

#If Win64 Then
Private Declare PtrSafe Function GdipGetLineColors Lib "gdiplus" (ByVal brush As LongPtr, color1 As Long, color2 As Long) As GpStatus
#Else
Private Declare Function GdipGetLineColors Lib "gdiPlus" (ByVal brush As Long, Colors As Any) As GpStatus
#End If

Thx!

[fafalone]

I see how the current definition is wrong, but not how that would be right? gdiplusflat.h:

GpStatus WINGDIPAPI
GdipGetLineColors(GpLineGradient *brush, ARGB* colors);

//gdipluspixelformats.h
typedef DWORD ARGB;

So the definition should be the same in both, Public Declare PtrSafe Function GdipGetLineColors Lib "gdiplus" (ByVal brush As LongPtr, colors As Long) As GpStatus because a DWORD is just a 4-byte Long on both 32bit and 64bit.

[GCuser99]

Oh, that's strange! You are right that:

Public Declare PtrSafe Function GdipGetLineColors Lib "gdiplus" (ByVal brush As LongPtr, colors As Long) As GpStatus

...works for both!

But the two-color argument version does "seem" to work for 64-bit and not 32-bit! Here is a snippet:

Dim Values(0 To 1) As Long
If GdipGetLineColors(BrushHandle, Values(0), Values(1)) = 0& Then

Maybe the second argument is superfluous and gets ignored?

Thanks!

[GCuser99]

Yeah, that is what it is... here is a test in tB which fails in 32-bit but works in 64-bit. Not sure what the expected behavior is (don't have VB6 to test).

Private Declare PtrSafe Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" ( _ 
    ByRef Destination As Any, _
    ByRef Source As Any, ByVal Length As Long, _
    ByVal superfluous As Long) '<-- added an unsupported argument

Sub test()
    Dim a As Long, b As Long
    a = 1: b = 2
    CopyMemory a, b, 4, 99999 '<-- fails in 32-bit tB with "Bad DLL Definition"
    Debug.Print a 'prints 2 in 64-bit tB
End Sub

[fafalone]

Well as long as the new version works in both 32bit and 64bit, I'll leave why the superfluous parameter works in 64bit as a mystery for those more familiar with the calling conventions on a low level.

Fixed in v7.8.379, available now.

Sorry for the multiple GDIP bugs; thanks for helping make WinDevLib better by reporting them though 👍