OpenEuphoria

Re: Help! GPF

• Posted by "Cuny, David" <David.Cuny at DSS.CA.GOV> Aug 05, 1999
• 494 views

Bernie wrote:

> Your definition of AppendMenuA is not correct
> in win32 library. It should be
> AppendMenuA { C_LONG, C_UINT, C_UINT, C_POINTER } C_INT

My documentation shows:

BOOL AppendMenu(
    HMENU hMenu,
    UINT uFlags,
    UINT uIDNewItem,
    LPCTSTR lpNewItem
   );

and I've always assumed that any handle reference gets coded as a C_POINTER
instead of C_LONG. Perhaps Rob could clear this up?

This doesn't appear to be a C_POINTER/C_LONG problem, because I'm passing
the handle to various Windows functions, and they seem to be working
properly - attaching the menu item to the menu, and so on. And, of course, I
tested it and it was still broken. But I *think* I know what the problem is,
although the logic still escapes me.

For reasons that still escape me, menu items and controls are ending up
sharing the *same* window handle. So when find() attempts to look the handle
up, it stops at the menu item, instead of finding the control. There are two
possibilities: I'm reading the handle wrong, or there really are duplicate
handles. Since code that uses these handles appears to work, my suspicion is
that the handles are not unique, and Windows relies on context to make sense
of them. If this is incorrect, someone please clue me in on what's really
going on.

Here's a dump of the window handles in an errant Win32Lib program:

  window_handle = {2652,2340,2340,2344,2344,2344,2348,
    2348,2348,2348,2348,2348,2348,2348,2348,2348,2348,
    2348,2348,2348,2352,2352,2352,2352,2352,2352,2356,
    2356,2656,2660,2664,2668,2672,2676,2680,2684,2688,
    2692,2696,2700,2708,2720,2716,2712,2724,2736,2108,
    2744,2728,2752,2748,2704,2732,2760,2740,1816,1888,
    1812,1876,1880,1828,1824,1820,1840,1836,1832,1884,
    1892,1896,1872,1704,1708,1848,1852,1856,1860,1864,
    1868,1844,1900,1808,1744,1736,1740,2764,2768,2400,
    2784,2776,2800,2252,2780,2772,2808,2796,2348,2840,
    2356,2340,2360,2424,2848,2344,2856,2852,2336,2836,
    2864,2868,2872,2876,2880,2884,2888,2892,2896,2900,
    2904,2908,2912,2916,2920,2924,2928,2932,2936,2940,
    2944,2948,2952,2956,2960,2964,2968,2972,2976,2980,
    2984,2988,2992,2996,3000,3004,3008,3012,3016,3020,
    3024}

There have always been duplicate handles in the window_handle list - for
example, the window handle of a MenuItem actually contains the handle of the
parent Menu. This doesn't cause problems with find(), since it stops at the
first control that it finds, and the window has to be defined before the
menu. Controls #2 and #3 show the sharing of a handle between a Menu and a
MenuItem.

The error is that control #83 is misidentified as #27 - they both share the
same value of 2356 as their handle.

There are several solutions I can think of:

   1. Exclude menus and menu items from the search
   2. Create another sequence of window and control handles
   3. Store the value in the GWL_USERDATA area

I'll probably go with option #3, since that's what Llama uses.

-- David Cuny