Borbin the 🐱

Ever run into this error message?

The error message 'Encountered an improper argument.' is from an uncaught exception in WindowProc.

In:

LRESULT CWinApp::ProcessWndProcException(CException* e, const MSG* pMsg)
    e->ReportError(MB_ICONEXCLAMATION|MB_SYSTEMMODAL, nIDP);

the error message is nIDP = AFX_IDP_INTERNAL_FAILURE:

#define AFX_IDP_INTERNAL_FAILURE        0xF108      // general failure

Usually you don't end up here. But there are cases where it happens. I have one example which was difficult to debug: An existing MFC based app upgraded to a ribbon control using a release build with static linking. Dynamic linked release builds and all debug builds are not affected.

It all starts at the InitInstance()of your app when you load the main frame:

pFrame->LoadFrame(IDR_MAINFRAME,
  WS_OVERLAPPEDWINDOW | FWS_ADDTOTITLE, NULL,
  NULL);

Then all the way down the call stack:

BOOL CFrameWndEx::LoadFrame(UINT nIDResource, DWORD dwDefaultStyle, CWnd* pParentWnd, CCreateContext* pContext)


BOOL CFrameWnd::LoadFrame(UINT nIDResource, DWORD dwDefaultStyle,
  CWnd* pParentWnd, CCreateContext* pContext)

BOOL CFrameWnd::Create(LPCTSTR lpszClassName,
  LPCTSTR lpszWindowName,
  DWORD dwStyle,
  const RECT& rect,
  CWnd* pParentWnd,
  LPCTSTR lpszMenuName,
  DWORD dwExStyle,
  CCreateContext* pContext)

BOOL CWnd::CreateEx(DWORD dwExStyle, LPCTSTR lpszClassName,
  LPCTSTR lpszWindowName, DWORD dwStyle,
  int x, int y, int nWidth, int nHeight,
  HWND hWndParent, HMENU nIDorHMenu, LPVOID lpParam)

until you reach:

ISOLATION_AWARE_INLINE HWND IsolationAwarePrivatenCv IsolationAwareCreateWindowExW(_In_ DWORD dwExStyle,_In_opt_ LPCWSTR lpClassName,_In_opt_ LPCWSTR lpWindowName,_In_ DWORD dwStyle,_In_ int X,_In_ int Y,_In_ int nWidth,_In_ int nHeight,_In_opt_ HWND hWndParent,_In_opt_ HMENU hMenu,_In_opt_ HINSTANCE hInstance,_In_opt_ LPVOID lpParam)

At this point you suddenly end up in the exception handler of the WndProc:

LRESULT AFXAPI AfxCallWndProc(CWnd* pWnd, HWND hWnd, UINT nMsg,
  WPARAM wParam = 0, LPARAM lParam = 0)

All class names, handles and sizes look alright. The last message is 5, which is a WM_SIZE message with the right lParam value. Usually you get a debug break and know why the exception was raised, but here it seemed a mystery. But a quick compare to a sample app from the templates revealed the solution: The ribbon required additional resources in order to run in a static release build in the .rc file:

#if !defined(_AFXDLL)
  #include "l.DEU\afxprint.rc"         // Ressourcen für Drucken/Seitenansicht
  #include "l.DEU\afxribbon.rc"        // Ressourcen für MFC-Menüband und -Steuerleiste
#endif

(Remove the language prefix 'l.DEU\' with your language code if you are building another language.)