Pointer query

[BackupUser]

Restored from previous forum. Originally posted by dmoc.

Which of these is correct and why?

hWnd = CreateWindowEx_(....
MoveWindow_(hWnd, ...

or...

*hWnd = CreateWindowEx_(....
MoveWindow_(*hWnd, ...

[BackupUser]

Restored from previous forum. Originally posted by tinman.

Originally posted by dmoc

hWnd = CreateWindowEx_(....
MoveWindow_(hWnd, ...

This one is probably the most correct. The reason is that Windows works mainly on handles, not pointers, so you have no way of being able to do "*hWnd\SomeFieldInTheStructure = $BAADC0DE" because a handle does not give you the direct address of something in memory.


--
It's not minimalist - I'm increasing efficiency by reducing input effort.
(Win98first ed. + all updates, PB3.51, Ed3.53)

[BackupUser]

Restored from previous forum. Originally posted by dmoc.

The PB Editor source uses the second form for all the rich edit gadgets. Confusing. I'm trying to resize a multi-line string gadget
created via CreateWindowEx_() and getting nowhere.

[BackupUser]

Restored from previous forum. Originally posted by tinman.

Originally posted by dmoc

The PB Editor source uses the second form for all the rich edit gadgets. Confusing. I'm trying to resize a multi-line string gadget
created via CreateWindowEx_() and getting nowhere.

From a point of view of whether the program works or not, both versions would work. It just needs to be a 32bit place to store some value.


Looking at the Windows header files I see that:

typedef void *HANDLE;

So the definition of the HANDLE type already includes the fact that this is a "pointer" to some non-descript type. But since you cannot do this in PB it will be defined as a long, which is good enough.
If you wrote HANDLE *hWnd in C you would effectively have a pointer to a pointer, giving you warnings but it would still work.



--
It's not minimalist - I'm increasing efficiency by reducing input effort.
(Win98first ed. + all updates, PB3.51, Ed3.53)

[BackupUser]

Restored from previous forum. Originally posted by dmoc.

OK, thanks, I'll experiment some more.

[BackupUser]

Restored from previous forum. Originally posted by tinman.

Originally posted by dmoc

OK, thanks, I'll experiment some more.

This works if you like, but it uses the wrong types (I wrote it some time ago

Code: Select all

If OpenWindow(0, 0, 0, 500, 500, #PB_Window_SystemMenu, "Scrollbar Example")
    If CreateGadgetList(WindowID())
        
        scrollbar.l = CreateWindowEx_(0, "ScrollBar", "", #WS_CHILD | #WS_VISIBLE | #SBS_VERT | #SBS_LEFTALIGN, 20, 20, 10, 50, WindowID(), 0, GetModuleHandle_(0), 0)
        SetWindowLong_(scrollbar, #GWL_ID, 3)

        params.SCROLLINFO
        params\cbSize = SizeOf(SCROLLINFO)
        params\fMask = #SIF_DISABLENOSCROLL | #SIF_PAGE | #SIF_POS | #SIF_RANGE
        params\nMin = 0
        params\nMax = 100
        params\nPage = 10
        params\nPos = 0
        SendMessage_(scrollbar, #SBM_SETSCROLLINFO, #TRUE, @params)
        
        ; This is how to resize an OS created gadget under PB
        MoveWindow_(scrollbar, 40, 40, 20, 300, #TRUE)
    EndIf
        
    While quitprog.w=0
        ev.l=WaitWindowEvent()
        Select ev
            Case #PB_Event_CloseWindow
                quitprog=1
        EndSelect
    Wend
EndIf
End

--
It's not minimalist - I'm increasing efficiency by reducing input effort.
(Win98first ed. + all updates, PB3.51, Ed3.53)

[BackupUser]

Restored from previous forum. Originally posted by dmoc.

Tinman, thanks for your help. Stupid me, I had deleted a global which
just happened to be the control's handle... duh... did yer know I'm
Homer's brother?