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c++wtl

Debug assertion in WTL splitter sample

When read or clear clipboard is clicked from the mainframe menu in the WTL sample compiled with vs2013

CHAIN_COMMANDS_MEMBER(m_wndFormatList) pases messages from the mainframe to the member list control but the message is null?

Stack trace:

WTLClipSpy.exe!ATL::CWindowImplRoot<WTL::CListViewCtrlT<ATL::CWindow> ::SetMsgHandled(int bHandled) Line 3213   C++
WTLClipSpy.exe!CClipSpyListCtrl::ProcessWindowMessage(HWND__ * hWnd, unsigned int uMsg, unsigned int wParam, long lParam, long & lResult, unsigned long dwMsgMapID) Line 30 C++
WTLClipSpy.exe!CMainFrame::ProcessWindowMessage(HWND__ * hWnd, unsigned int uMsg, unsigned int wParam, long lParam, long & lResult, unsigned long dwMsgMapID) Line 41   C++

Debug output:

Debug Assertion Failed!

Program: ...nloads\source\WTL4MFC7_demo\WTLClipSpy.\Debug\WTLClipSpy.exe File: c:\program files (x86)\microsoft visual studio 12.0\vc\atlmfc\include\atlwin.h Line: 3213

Expression: pMsg != 0

Solution

  • It is likely to be a regression problem with a not so popular CHAIN_COMMANDS_MEMBER macro.

    A workaround might look like this:

        //CHAIN_COMMANDS_MEMBER(m_wndFormatList)
    if(uMsg == WM_COMMAND)
    {
        lResult = m_wndFormatList.SendMessage(uMsg, wParam, lParam);
        if(lResult == 0)
            return TRUE;
    }

    Or, if you prefer to bypass SendMessage API (makes sense), then you will need to take care of m_pCurrentMsg initialization in the chained control. A better but longer fix.