C / C++ / MFC

David Crow19-Oct-09 3:18

David Crow

19-Oct-09 3:18

There must be something special about the WM_CLOSE message. Are you using a DLL? Are you calling SetWindowLong() in that DLL? Are you injecting the DLL into the process of the "specific window?"

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[N][Q][H]19-Oct-09 5:09

[N][Q][H]

19-Oct-09 5:09

Because this is a global hook which will monitor all message before they really reach to target window. So I think It doesn't need inject the dll to the target window. But I will try.

I took a round from google and know that many people have the same problem with me when they try to catch the WM_CLOSE. But I still cannot find the solution.

[N][Q][H]

Naveen19-Oct-09 3:41

Naveen

19-Oct-09 3:41

[N][Q][H] wrote:
DLLEXPORT LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam, LPARAM lParam)

You hook handler seems to be incorrect. For instance if you are using the WH_CALLWNDPROC, the handler should be like

LRESULT CALLBACK CallWndProc(int nCode,WPARAM wParam, LPARAM lParam)
{
	PCWPSTRUCT msg = (PCWPSTRUCT)lParam;

	   if(msg->message == WM_CLOSE )
	   {
		  //do somethings here
		
	   }	
	   return CallNextHookEx(_hHook,nCode,wParam, lParam);
}

nave

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[N][Q][H]19-Oct-09 5:01

[N][Q][H]

19-Oct-09 5:01

ok, KeyboardProc must be renamed to fnHookProc. But this is not the cause. This just a mistake when I copy from my code.

LRESULT CALLBACK LRESULT CALLBACK fnHookProc(int nCode,WPARAM wParam, LPARAM lParam)
{
	PCWPSTRUCT msg = (PCWPSTRUCT)lParam;

	   if(msg->message == WM_CLOSE )
	   {
		  //do somethings here
		
	   }	
	   return CallNextHookEx(_hHook,nCode,wParam, lParam);
}

[N][Q][H]

Help with global variable in MFC dialog application

carly3321-Oct-09 0:38

carly33

21-Oct-09 0:38

It's an old Win32 FAQ (see onWin32 grp[^]) (same method than on Win 9x)

moh.hijjawi19-Oct-09 1:04

Re: Help with global variable in MFC dialog application

19-Oct-09 1:04

Dear all,

I am using MFC dialog application to get an text input from the user and make processing on it and then reply with response but I need to declare some variables to be working throughout the whole system cycle(I think its called global variables) to be accessible whereever from my system coding files. Because I need to deal with the variable changes during the system cycle.

I tired many things Like: static ,extern. But till now I'm beginner in this language so I didn't know how to deal with them in .cpp files.

Please any help will be appreciated.

Best regards.

CPallini19-Oct-09 1:54

Re: Help with global variable in MFC dialog application

19-Oct-09 1:54

If you need a global variable in your application, then you have an example at hand: the variable theApp (have look at it in your application). You may use the same route for your own global variable: declare it as extern in the main header of your application (the one included by all the - or the relevant - sources and define it in the main source. For instance, suppose your application name is test, then in test.h:

// test.h
extern int g_iMainCounter;

and in test.cpp

// test.cpp
int g_iMainCounter;

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-- Alfonso the Wise, 13th Century King of Castile.

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moh.hijjawi19-Oct-09 2:53

Re: Help with global variable in MFC dialog application

19-Oct-09 2:53

Thank you for your reply and its work fine only when I want to use the variable in test.cpp. and in testDlg.cpp because you know I'm using dialog application.

But I tried to use the same variable in different files inside the same application for example in XX.cpp its already undeclared identifier there and I tried to include the header file #include "XX.h" and I can't access this variable.

Please help me.

And thanks alot again.

Hans Dietrich19-Oct-09 2:59

Hans Dietrich

19-Oct-09 2:59

You need to include "test.h".

Best wishes,
Hans

[Hans Dietrich Software]

Re: Help with global variable in MFC dialog application

CPallini19-Oct-09 3:02

Re: Help with global variable in MFC dialog application

19-Oct-09 3:02

moh.hijjawi wrote:
But I tried to use the same variable in different files inside the same application for example in XX.cpp

You have to options:

include test.h in XX.cpp.
declare the variable as extern inside XX.h (or XX.cpp).

moh.hijjawi19-Oct-09 5:30

Re: Help with global variable in MFC dialog application

19-Oct-09 5:30

Thank you for all of you.

I included test.h but it doesn't work as well But it works when I declare it as external inside XX.cpp so its now work fine.

Really you save my time with your experince and many thanks.

Regards. Big Grin | :-D

CPallini19-Oct-09 8:04

Re: Help with global variable in MFC dialog application

19-Oct-09 8:04

You are welcome. Smile | :)

moh.hijjawi30-Oct-09 2:52

Mutexes and WaitForSingleObject -> doesn´t wait ??

30-Oct-09 2:52

Hi
I come back to make updating on this function to make the initialization for these variables through function and this function should bring the values from DB.

I am struggling with where I should declare the function and where I could call this function to be luncing once the MFC dialog interface launched. I tried many ways but always the compiler inform me that "unresolved external symbol" for the used external variables.

I tried to put the function declaration as a member function in the testApp class //but failed

I tried to put the function declaration as a member function in the ZZ.cpp and make the proper including //but failed and inform me that you can't initialize them into closed scope.

it seems to me that the initialization should be in the test.cpp and without function using. I don't believe that but how I can make it.

Any help will be appreciated Big Grin | :-D

Souldrift19-Oct-09 0:41

Souldrift

19-Oct-09 0:41

Hello,

I just played around with mutexes and wrote the following piece of code:

HANDLE hMutex = CreateMutex(NULL,	// no security descriptor needed in the beginning
                            TRUE,       // not initial owner
                            "test");    // mutex name (hopefully unique)

DWORD err = WaitForSingleObject(hMutex, INFINITE);
if( err == WAIT_FAILED )
	printf( "This shouldn´t happen." );
else
{
	err = WaitForSingleObject(hMutex, INFINITE);
	if( err == WAIT_FAILED )
		printf( "This shouldn´t happen." );
	else
		printf( "This shouldn´t happen either." );
}

No I don´t understand why the second WaitForSingleObject()-call doesn´t block. Since I said to wait indefinitely, shouldn´t it do so because the mutex object is already in use?
I guess, I have some general trouble understanding the mechanism here. How do I get the mutex to lock a code area up?

Souldrift

Re: Mutexes and WaitForSingleObject -> doesn´t wait ??

Michael Schubert19-Oct-09 0:53

Michael Schubert

19-Oct-09 0:53

Whay don't you use GetLastError() when the return value is WAIT_FAILED as the documentation suggests?

Re: Mutexes and WaitForSingleObject -> doesn´t wait ??

Souldrift19-Oct-09 0:56

Souldrift

19-Oct-09 0:56

There is no error. The return value both times is 0. Which is fine with the first call, and I thought was odd with the second.
But I just read somewhere else, that mutexes under windows don´t block inside the same thread. So that might be it.

Souldrift

Re: Mutexes and WaitForSingleObject -> doesn´t wait ??

CPallini19-Oct-09 0:58