loading dll second time giving error "A required resource was unavailable"

[sujan.dasmahapatra]

I am loading an extension dll from my mfc client application, when click on the menu first time the dll dialog is being loade and after i exit or close the dialog, and again clicking on the menu to load again it's giving error that "A required resource was unavailable". what could be the problem please help me to resolve this

void CTestRevApp ::On3DView()
{
    typedef VOID (*MYPROC)(CString);
    
	MYPROC ProcAdd;
    BOOL fRunTimeLinkSuccess = FALSE;

    
	hinstLib = LoadLibrary(L"C:\\Documents and Settings\\sdh\\My Documents\\REVOLUTIONPROJ_DB\\DllDialog\\package\\DllTest\\Release\\dlltest.dll");
	
	if( hinstLib == NULL)
	   FreeLibrary(hinstLib);
 

	ProcAdd = (MYPROC)GetProcAddress(hinstLib, "runAppli");
	ProcAdd(NULL);
	if(ProcAdd == NULL)
	{
		AfxMessageBox(L"Unable to get pointer to function runAppi()");
	    FreeLibrary(hinstLib);
	    hinstLib = NULL;
		return;
    }
    
	return;
}

[sujan.dasmahapatra]

can anyone give your mail id so that I can send you the project ?? can u help me ?

[VictorN]

I am loading an extension dll from my mfc client application, when click on the menu first time the dll dialog is being loade and after i exit or close the dialog, and again clicking on the menu to load again it's giving error that "A required resource was unavailable". what could be the problem please help me to resolve this

Did you debug your code?
What line (exactly!) in this code snippet causes this error?

PS: You can attach your project (in zip archive excluding Debug and Release folders as well as .ncb, .aps, .clv files) to your post

[sujan.dasmahapatra]

I have got the problem I have implemented the PrecreateWindow for my view class.
just check this code.

BOOL CMyView::PreCreateWindow(CREATESTRUCT& cs)
{
	cs.lpszClass = ::AfxRegisterWndClass(CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS | CS_OWNDC,::LoadCursor(NULL, IDC_ARROW), NULL, NULL);

    cs.style |= WS_CLIPSIBLINGS | WS_CLIPCHILDREN;

    cs.dwExStyle = WS_EX_CLIENTEDGE; 

	return CView::PreCreateWindow(cs);
}

If I remove the first line, i.e
cs.lpszClass = ::AfxRegisterWndClass(CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS | CS_OWNDC,::LoadCursor(NULL, IDC_ARROW), NULL, NULL);
then my dll window is coming all the times from the client call. But it's flickering .
So now please help me what can I do to resolve this. I think some of you must have understood the problem, please help me. Thanks a lot.

[Peter_B]

There are a few problems with your code - I have highlighted these with comments in red:

void CTestRevApp ::On3DView()
{
    typedef VOID (*MYPROC)(CString);
    
	MYPROC ProcAdd;
    BOOL fRunTimeLinkSuccess = FALSE;

    
	hinstLib = LoadLibrary(L"C:\\Documents and Settings\\sdh\\My Documents\\REVOLUTIONPROJ_DB\\DllDialog\\package\\DllTest\\Release\\dlltest.dll");
	
	if( hinstLib == NULL)
	   FreeLibrary(hinstLib); // No need to call FreeLibrary on a NULL value - you should just give an error message and return
 

	ProcAdd = (MYPROC)GetProcAddress(hinstLib, "runAppli");
	ProcAdd(NULL); // What is this line meant to do? You declared MYPROC to be a function which takes a CString, not a pointer. Also, you should not call it before checking for NULL
	if(ProcAdd == NULL)
	{
		AfxMessageBox(L"Unable to get pointer to function runAppi()");
	    FreeLibrary(hinstLib); // Shouldn't you Free the DLL always, whether or not you find the "runAppli" function?
	    hinstLib = NULL;
		return; // No need to return here, as execution would just fall through to the end of function anyway
    }
    
	return;
}