C / C++ / MFC

Problem when using DllMain() function

15-Dec-07 3:28

Have a look at http://msdn2.microsoft.com/en-us/library/zebw5zk9(VS.80).aspx[^]
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

ashishbhatt15-Dec-07 2:06

ashishbhatt

15-Dec-07 2:06

Hi All,

I have very serious problem regarding using DllMain() function in my application.I have created MFC Activex Control in VS2005.

I have created one .cpp file in that I want to use DllMain() function as below....

BOOL WINAPI DllMain (HANDLE hInst, ULONG ul_reason_for_call, LPVOID lpReserved)<br />
{<br />
    /// Any Code.....<br />
}

But when I use this function (At least these three lines.. Sigh | :sigh:

) I got an error like below....

Hooking.obj : error LNK2005: _DllMain@12 already defined in mfcs80ud.lib(dllmodul.obj)<br />
ActivexVS05.ocx : fatal error LNK1169: one or more multiply defined symbols found

I have searched for this error in google but I could not found the solution.

If you have any suggetion and solution then please reply me.

Thanks in Advance.

Re: Problem when using DllMain() function

Mike Dimmick15-Dec-07 7:53

Mike Dimmick

15-Dec-07 7:53

MFC implements DllMain for you. Override the InitInstance method instead.

Read the DllMain[^] article very carefully, and the Best Practices for Creating DLLs[^] white paper. Note particularly that calling MFC methods may not be safe if MFC has not yet initialised, if you're using MFC in a shared DLL.

In general I would recommend avoiding any initialisation steps in DllMain and instead perform them in the class itself (perhaps in the constructor).

DoEvents: Generating unexpected recursion since 1991

Re: Problem when using DllMain() function

ashishbhatt15-Dec-07 17:27

ashishbhatt

15-Dec-07 17:27

Hi,,

Sorry for the very late reply.

Thank you very much for reply.I have read the article as you told and I have solved this problem but now I am facing new problem regarding this topic.

Now I am using below code for the my project purpose using Dllmain().Here I have created one DLL in that I am using this function.In this DLL what happens that this DLL checks for screen update and mouse update on the desktop and sends messsages to my MFC Activex Control (which is another project in the same Solution).

<br />
 // The DLL's main procedure<br />
BOOL WINAPI DllMain (HANDLE hInst, ULONG ul_reason_for_call, LPVOID lpReserved)<br />
{<br />
   // Save the instance handle<br />
   hInstance = (HINSTANCE)hInst;<br />
<br />
   // Any code.......<br />
<br />
   return TRUE;<br />
}<br />

And now problem is when I run my Activex from Activex control test Container then whenever this test container is active on top of the desktop then messages(like Scrren update,,Mouse update)are peeked up by Activex control application but when any other window is active then these messages are not peeked by Activex.

Is the problem with this hInstance which get the instance of the window in which My Activex is running???

I ahve tested running my activex in explorer but the same problem exists.

I peeked up these messages from my Activex by below code....

<br />
   MSG msg;<br />
   while(1)<br />
   {<br />
      if(!PeekMessage(&msg,m_desktop->m_hwnd,NULL,NULL,PM_REMOVE))<br />
      {<br />
        if(!m_desktop->CheckUpdate())<br />
           break;<br />
        if (!WaitMessage())<br />
        {<br />
	  AfxMessageBox(CString("WaitMessage Failed"));<br />
	  break;<br />
        }<br />
      }<br />
      else if(msg.message ==  SCREEN_UPDATE)<br />
      {<br />
         // Any code......<br />
      }<br />
      else if(msg.message == MOUSE_UPDATE)<br />
      {<br />
        // Any code.......<br />
      }<br />
      <br />
   }<br />

Please give me any suggetion if you have any idea or ask me if you have any more quetions.

Thanks in Advance.

Ashish Bhatt

Re: Problem when using DllMain() function

Mark Salsbery15-Dec-07 8:07

Mark Salsbery

15-Dec-07 8:07

Also, study this to make sure you're using the correct form of MFC DLL
and initializing it properly...

Kinds of DLLs[^]

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

GDI+ How to mask an image with a mask bitmap

followait15-Dec-07 2:00

Re: GDI+ How to mask an image with a mask bitmap

15-Dec-07 2:00

For example, there are two images with the same size.
One is a normal pic, the other is a mask bitmap.
The colors in the mask one are composed with black and white (including gray).
Now let gray level become transparency.
Put the mask bitmap onto the normal one, and get the image.
How to do it with GDI+?
Thnaks.

Mark Salsbery15-Dec-07 8:11

Mark Salsbery

15-Dec-07 8:11

AFAIK, GDI+ doesn't have built-in code for image masks. Transparency is handled with alpha
channel instead.

You could step through the pixel values of the mask and based on each value, adjust the
alpha value of each pixel in the other bitmap.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: GDI+ How to mask an image with a mask bitmap

followait15-Dec-07 14:19

CListCtrl in CDialogBar can't receive WM_CREATE

15-Dec-07 14:19

Yes, I'll do this way.

Thanks.

followait15-Dec-07 1:29

Re: CListCtrl in CDialogBar can't receive WM_CREATE

15-Dec-07 1:29

I want to init CListCtrl, m_hWnd of CListCtrl must be available,
where to put the init code?

CPallini15-Dec-07 1:49

Re: CListCtrl in CDialogBar can't receive WM_CREATE

15-Dec-07 1:49

Can you reformulate you question (give more details)?
Confused | :confused:

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

followait15-Dec-07 2:06

Re: CListCtrl in CDialogBar can't receive WM_CREATE

15-Dec-07 2:06

class CMyDialogBar:public CDialogBar
{
...
public:
    CMyListCtrl m_list;   //it has been associated with a list ctrl
...
}

CMyListCtrl::OnCreate()   //ON_WM_CREATE
{
//never reach here, why?
}

CPallini15-Dec-07 2:44

Re: CListCtrl in CDialogBar can't receive WM_CREATE

15-Dec-07 2:44

Does your CMyListCtrl inherits from CListCtrl?
Can you detail a little more (sorry for the insistence)?
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

Hamid_RT15-Dec-07 3:16

Hamid_RT

15-Dec-07 3:16

How did you make your listbox? visual or dynamic

Re: CListCtrl in CDialogBar can't receive WM_CREATE

followait15-Dec-07 14:20

Re: CListCtrl in CDialogBar can't receive WM_CREATE

15-Dec-07 14:20

visual

Hamid_RT15-Dec-07 18:25

Hamid_RT

15-Dec-07 18:25

So you can declare a variable for it and use of its hWnd.(m_ListCtrl.m_hWnd)

Re: CListCtrl in CDialogBar can't receive WM_CREATE

Jörgen Sigvardsson15-Dec-07 11:04

Jörgen Sigvardsson

15-Dec-07 11:04

Because the list control is already created by the time it is attached to your CListCtrl variable.

--
Kein Mitleid Für Die Mehrheit

Re: CListCtrl in CDialogBar can't receive WM_CREATE

followait15-Dec-07 14:22

default implementation of assignment operator

15-Dec-07 14:22

When not in a dialog bar, it is ok.

George_George14-Dec-07 19:04

Re: default implementation of assignment operator

14-Dec-07 19:04

Hello everyone,

I am wondering the default implementation of assignment operator (e.g. when we do not implement assignment operator in user defined class, what will be returned? temporary object? reference or const reference? deep copy or shallow copy is used in default assignment operator?)? I have the C++ Programming Book at hand, but can not find it from Index page.

thanks in advance,
George

CPallini15-Dec-07 0:45

Re: default implementation of assignment operator

15-Dec-07 0:45

George_George wrote:
I am wondering the default implementation of assignment operator (e.g. when we do not implement assignment operator in user defined class, what will be returned? temporary object? reference or const reference?

A reference. (*this).

George_George wrote:
deep copy or shallow copy is used in default assignment operator?

Shallow copy.

Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

George_George15-Dec-07 4:01

15-Dec-07 4:01

Thanks CPallini,

My question is answerd! Cool!

have a nice weekend,
George

Thanks

CPallini15-Dec-07 5:21

non-const reference and const reference

15-Dec-07 5:21

George_George wrote:
have a nice weekend

Thank you. Have a nice weekend you too.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

George_George14-Dec-07 17:48

Re: non-const reference and const reference

14-Dec-07 17:48

Hello everyone,

This is my understanding of non-const reference, const reference and their relationships with lvalue/rvalue. Please help to review whether it is correct and feel free to correct me. Thanks.

1. A const reference can be binded to a rvalue, for example, a temporary object. And the "life" of the temporary object is guaranteed to be extended and we can safely operate through the const-reference.

2. A non-const reference can not binded to a rvalue, I think the reason is rvalue is not addressable? And we can not change the rvalue through its reference? Are there any other reasons? I am not quite sure whether my understanding is fully correct. Since there are some non-modifiable lvalues (so we do not always need to modify values through its reference). I am still studying what is the reason in essence in compiler why a non-const reference can not be binded to a rvalue.

3. Both const and non-const reference can be binded to a lvalue.

thanks in advance,
George

Iain Clarke, Warrior Programmer14-Dec-07 22:36

Iain Clarke, Warrior Programmer

14-Dec-07 22:36

I've just answered your question. If you remember, you asked this question yesterday.

I've admit, todays question is better phrased, but still...

Have *SOME* patience.

Iain.

Re: non-const reference and const reference

George_George15-Dec-07 4:02