FindWindowEx() fails with ToolTip class

FindWindowEx() is failing silently when I ask it to find the handle of my toolTip window. Here is my toolTip generation code:

Code:

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HWND createTooltip(HWND hwnd){
    INITCOMMONCONTROLSEX iccex;
    /* INITIALIZE COMMON CONTROLS */
    iccex.dwICC = ICC_WIN95_CLASSES;
    iccex.dwSize = sizeof(INITCOMMONCONTROLSEX);
    InitCommonControlsEx(&iccex);

    HWND hwndTT = CreateWindowEx(WS_EX_TOPMOST, TOOLTIPS_CLASS, NULL,
                                WS_POPUP | TTS_NOPREFIX | TTS_ALWAYSTIP,
                                CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
                                hwnd, NULL, GetModuleHandle(NULL), NULL);

    SetWindowPos(hwndTT, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOACTIVATE);

    return hwndTT;
}

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And here is my code calling FindWindowEx:

Code:

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HWND hTT = FindWindowEx(hwnd, NULL, TOOLTIPS_CLASS, NULL);

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My parent window handle (hwnd) is the same handle I supplied during the ToolTip's creation; but despite this,
FindWindowEx returns NULL and sets GetLastError to 0; where, according to microsoft's defintion here, it should be returning the handle to my ToolTip window. Exactly why does it refuse to do this?

Your tooltip is an owned window, rather than a child window (child windows have the WS_CHILD style).

I don't know of any neat way of iterating owned windows of a particular window but you could try iterating all top-level windows (using EnumWindows or FindWindowEx) and checking if they are owned by your target window (using GetWindow with GW_OWNER).

Typically, you would just store the window handle.

Hey thanks anony! I've been running into a lot of these problems between child vs owned windows lately (i.e GetParent() vs GetWindow())...
The EnumWindows solution sounds good, I think I'll go with that. But when you say store the window handle, you mean globally?

Globally or as the member of a class that is globally available, or at least everywhere you need it. Point is, the HWND should be available where you need it, and you should never have to search for your own windows.