C / C++ / MFC

Albert Holguin13-Jan-12 12:05

Albert Holguin

13-Jan-12 12:05

Global is probably not the best option in C++, but I'll answer your question nonetheless...

In main.h, where did you declare mysql5? Is it in the global namespace or is it in a class? If it's in the global namespace, you probably have to remove the static declaration since that'll limit the visibility of the variable.

Assuming it is in the global namespace, in income.cpp, did you remember to declare mysql5?

extern MYSQL *mysql5;

Lastly... in C++, it's probably a better idea to use a member variable and pass the parameter that way when the object is constructed or through a Set() method.

1.fcb191314-Jan-12 0:35

1.fcb1913

14-Jan-12 0:35

Thank you for the answear.
If I remove the static declaration I receive errors like this : error LNK2005: "struct st_mysql * mysql5" (?mysql5@@3PAUst_mysql@@A) already defined in main.obj.
Adding

extern MYSQL *mysql5;

do nothing.
Here are details:

//main.cpp - contains WindowProc, int WINAPI _tWinMain(...) ...
main.h:
#include "ClassLogin.h"
static MYSQL *mysql5;
static ClassLogin *login2;

DlgLogin.cpp - contains dialog procedure and #include "main.h" 
case button_OK:
ClassLogin * login = new ClassLogin(...parameters...);
login2 = login;
 
//Class ClassLogin:
ClassLogin.cpp: 
#include "main.h"
#include "ClassLogin.h"
ClassLogin::ClassLogin();
ClassLogin::ClassLogin(...parameters...)
{ ... mysql_real_connect(Cmysql, host, user, password , database , port, unix, 0 );
mysql5 = Cmysql; }
destructor

//ClassLogin.h: 
Class ClassLogin
{
public:
ClassLogin();
ClassLogin(...parameters...);
MYSQL *Cmysql;
virtual ~ClassLogin();
};

income.cpp - contains dialog procedure and 
#include "main.h"
#include "ClassLogin.h"
MYSQL * mysql2;
case button_OK:
mysql2 = login2->Cmysql;// value login2->Cmysql is 0x00000000
mysql2 = mysql5;// value mysql5 is 0x00000000

But if I don't use login2->Cmysql or mysql2 = mysql5 the values are right (0x01df0a98) while debuging (F5)
What I have to do to obtain values from class ClassLogin in another cpp file?
Jan

CPallini14-Jan-12 2:21

14-Jan-12 2:21

You may:
in main.h remove the line

C++

static MYSQL *mysql5;

in DlgLogin.cpp add the line

C++

MYSQL * mysql5;

in income.cpp add the line

C++

extern MYSQL * mysql5;

Now the variable in income.cpp is exactly the same of DlgLogin.cpp so no assignemnt is required.
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.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

1.fcb191314-Jan-12 3:04

1.fcb1913

14-Jan-12 3:04

Thank you. This function. Thumbs Up | :thumbsup:

CPallini14-Jan-12 4:19

How to respond to WSAETIMEDOUT in CSsyncsocket::onconnect

14-Jan-12 4:19

Well, I had no doubt about... Big Grin | :-D

You are welcome.

ForNow13-Jan-12 7:07

Re: How to respond to WSAETIMEDOUT in CSsyncsocket::onconnect

13-Jan-12 7:07

I have a two folded question

1) How to respond to

WSAETIMEDOUT

in the OnConnect override for CASyncSocket
where nErrorcode = WSAETIMEOUT

2) My CASyncsocket class "Mysocket" is a member of CWinThread Class as I want to make where
the socket class lives the highest priority

if the answer to question 1 call CASyncsocket::connect again then how would I obtain
my CWinThread class which has my CAsynsocket class a member

for example
MyCAsynSocket* currentthread;
class MyCwinThread : public CWinthread
{
.
.
.
.
CAsynSocket MyCAsynSocket;
CString ipaddr;
UINT port;
}
currentthread = (MyAsynSocket*) = AFxGetthread(): //

currentthread->connect(currentthread>ipaddr,currentthread->port);

Thanks

Chris Meech13-Jan-12 7:22

Chris Meech

13-Jan-12 7:22

Not sure what you are trying to explain or do here, but this line of code looks really incorrect.

currentthread = (MyAsynSocket*) = AFxGetthread(): //

Also in terms of trying to connect again, can you not wrap the connect call within some kind of loop operation? Smile | :)

Chris Meech
I am Canadian. [heard in a local bar]

In theory there is no difference between theory and practice. In practice there is. [Yogi Berra]

posting about Crystal Reports here is like discussing gay marriage on a catholic church’s website.[Nishant Sivakumar]

dll loading itself launching the application

appollosputnik12-Jan-12 2:42

appollosputnik

12-Jan-12 2:42

Dear Friends
I am loading a dll from another exe mfc application. for that i have exposed one api 'runAppli' in the dll as extern "C". Then I am loading the dll using LoadLibrary. By loading the dll itself the dll application is launched. I am surprised. I should call the api 'runAppli' and then the application should launch but its not happening. How come it is happening please give some suggestions.

[code]
// in the all
extern "C" BOOL __declspec(dllexport) runAppli(CString filename)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState());
if(filename.IsEmpty())
return false;
view->ShowWindow(SW_SHOW);
view->loadProfile(filename);
view->domainSetUpForProfile();
view->drawLines();
view->drawArcs();
view->drawProfile();
return true;
}

//in the client exe application

void CClientRevolutionProjDlg::OnBnClickedButton1()
{
HINSTANCE hinstLib;
hinstLib = LoadLibrary(L"C:\\Users\\sujan.dasmahapatra\\Documents\\Projects\\Bhagavan_SurfaceRevolution\\RevolutionProj\\debug\\RevolutionProj.dll");
}
[\code]

By simply loading the dll the dll application is launching.. why ??? Thanks Sujan

Re: dll loading itself launching the application

C^hris L^osinger12-Jan-12 3:50

C^hris L^osinger

12-Jan-12 3:50

it's impossible for us to say, without knowing what the DLL has in its DllMain (or CWinApp::InitInstance).

image processing toolkits | batch image processing

Re: dll loading itself launching the application

Randor 12-Jan-12 13:31

Randor

12-Jan-12 13:31

Hi,

The MFC DllMain function will automatically call InitInstance when your DLL is loaded and it also calls ExitInstance when the DLL is unloaded.

You might be able to get around this by providing your own DllMain function:

HOWTO: How to Provide Your Own DllMain in an MFC Regular DLL[^]

I don't really recommend providing your own Dllmain function... you could probably prevent the window creation by modifying your InitInstance and removing/moving the window/view initialization.

Best Wishes,
-David Delaune

Learn MFC

columbos1492711-Jan-12 19:22

columbos14927

11-Jan-12 19:22

Hello,
Ive been programing in MFC for a while.
And now i would like to learn MFC deeper and to understand better what is going on behind the scene.
What good books exist for learning MFC?

Re: Learn MFC

«_Superman_»11-Jan-12 19:46

«_Superman_»

11-Jan-12 19:46

Here are 2 books that I recommend -
Programming Windows with MFC, Second Edition[^]
MFC Internals: Inside the Microsoft(c) Foundation Class Architecture[^]

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

Proper response From WSAEWOULDBLOCK return code From CAsyncSocket::Connect

ForNow11-Jan-12 10:24

Re: Proper response From WSAEWOULDBLOCK return code From CAsyncSocket::Connect

11-Jan-12 10:24

Hi,

I got a

WSAEWOULDBLOCK

return code from the connect method would the proper
response be to retry the operation until I get a Zero return code

CPallini11-Jan-12 10:45

Re: Proper response From WSAEWOULDBLOCK return code From CAsyncSocket::Connect

11-Jan-12 10:45

As MSDN suggests[^]:

If this indicates an error code of WSAEWOULDBLOCK, and your application is using the overridable callbacks, your application will receive an OnConnect message when the connect operation is complete

you shouldn't call again the Connect method because the connect operation is in progress after method returns. Viceversa, you should override the OnConnect method (see the example in its documentation[^]) to know when the connect operation is completed.

ForNow11-Jan-12 14:36

Re: Proper response From WSAEWOULDBLOCK return code From CAsyncSocket::Connect

11-Jan-12 14:36

I did that and i got WSAETIMEDOUT as the nerror code any way to set the time out value for more time

thanks

CPallini11-Jan-12 22:08

Re: Proper response From WSAEWOULDBLOCK return code From CAsyncSocket::Connect

11-Jan-12 22:08

This time it is properly an error and you have to call again the Connect method. I don't know if you may change the timeout value.

ForNow12-Jan-12 12:19