INT_PTR SomeFunction(HWND hWndChild, TOOLINFO *pTI)
{
    if (hWndChild != NULL) // Your HWND being tested
    {
        // return positive hit if control ID isn't -1
        INT_PTR nHit = _AfxGetDlgCtrlID(hWndChild);
        // Replace with GetDlgCtrlID().

        // hits against child windows always center the tip
        if (pTI != NULL && pTI->cbSize >= sizeof(AFX_OLDTOOLINFO))
        {
            // setup the TOOLINFO structure
            pTI->hwnd = m_hWnd;
            pTI->uId = (UINT_PTR)hWndChild;
            pTI->uFlags |= TTF_IDISHWND;
            pTI->lpszText = LPSTR_TEXTCALLBACK;

            // set TTF_NOTBUTTON and TTF_CENTERTIP if it isn't a button
            if (!(::SendMessage(hWndChild, WM_GETDLGCODE, 0, 0) & DLGC_BUTTON))
                pTI->uFlags |= TTF_NOTBUTTON|TTF_CENTERTIP;
        }
        return nHit;
    }
    return -1;  // not found
}

HWND hToolTipWnd = NULL;

BOOL GetToolTipText(HWND hWnd, UINT nId, std::wstring& strTooltip)
{
    hToolTipWnd = NULL;
    EnumWindows(FindToolTip, (LPARAM)hWnd);

    if (hToolTipWnd == NULL)
        return FALSE;

    WCHAR szToolText[256];
    TOOLINFO ti;
    ti.cbSize = sizeof(ti);
    ti.hwnd = hWnd;
    ti.uId = nId;
    ti.lpszText = szToolText;

    SendMessage(hToolTipWnd, TTM_GETTEXT, 256, (LPARAM)&ti);
    strTooltip = szToolText;

    return TRUE;
}

BOOL CALLBACK FindToolTip(HWND hWnd, LPARAM lParam)
{
    WCHAR szClassName[256];
    if (GetClassName(hWnd, szClassName, 256) == 0)
        return TRUE;

    if (wcscmp(szClassName, L"tooltips_class32") != 0)
        return TRUE;
    if (GetParent(hWnd) != (HWND)lParam)
        return TRUE;

    hToolTipWnd = hWnd;

    return FALSE;
}