C / C++ / MFC

Re: pointer to property page

3-Sep-02 0:50

When you add pages to the propertysheet can't you add a pointer to the CPage1 to CPage2?

Asim Hussain
e: asim@jawache.net
w: www.jawache.net

Pavel Klocek3-Sep-02 0:50

Pavel Klocek

3-Sep-02 0:50

In CPage1:

((CMyPropertySheet*)GetParent())->m_page2

Pavel
Sonork 100.15206

FILE and _FILEX problems..

Jawache3-Sep-02 0:41

3-Sep-02 0:41

I am openeing a file using fopen and FILE*.

I am getting problems with this structure later It seems to think the FILE is a
_FILEX structure?!?!?!

When I open the file the call stack is.

fopen
_fsopen
_getstream

and the _getstream function definately returns a FILE object in the line

stream.c >>>>>>

retval = (FILE *)__piob[i];

but later it tries to read from the FILE stream using fgets. The call stack here
is

fgets
_lock_file

There is an exception in _lock_file I've figured out what it is and basicaly the
system thinks the FILE structure is a _FILEX structure and tries to access a non
existant member variable so it asserts.

void __cdecl _lock_file (
        void *pf
        )
{
        /*
         * The way the FILE (pointed to by pf) is locked depends on whether
         * it is part of _iob[] or not
         */
        if ( (pf >= (void *)_iob) && (pf <= (void *)(&_iob[_IOB_ENTRIES-1])) )
            /*
             * FILE lies in _iob[] so the lock lies in _locktable[].
             */
            _lock( _STREAM_LOCKS + ((FILE *)pf - _iob) );
        else
            /*
             * Not part of _iob[]. Therefore, *pf is a _FILEX and the
             * lock field of the struct is an initialized critical
             * section.
             */
            EnterCriticalSection( &(((_FILEX *)pf)->lock) );
}

An exception is raised at
EnterCriticalSection( &(((_FILEX *)pf)->lock) );

I have a STRONG suspision its a simple project settings or maybe library linkage
problem since I have the exact same code in another application and it works
fine....

Working on VC6 SP5
Windows 2000 SP2

Asim Hussain
e: asim@jawache.net
w: www.jawache.net

Tomasz Sowinski3-Sep-02 0:48

3-Sep-02 0:48

Seems like you're mixing code using single-threaded and multi-threaded CRT. FILEX is just FILE in single-threaded CRT. In MT version, FILEX aggregates FILE with critical section.

Tomasz Sowinski -- http://www.shooltz.com

** Putt knot yore thrust inn spel chequers. **

Jawache3-Sep-02 0:59

3-Sep-02 0:59

Thats a bit weird.

I had another look at my settings and changed from Static Linkage to Dynamic Linkage, In statis linkage it was using the Debug Multithreaded Archive and having the problems and in the dynamic linked build its using the Dynamic Multithreaded DLL and now it works?

Is this an issue with the Archive vs the DLL ? As I would really like to finaly make a static build and stop with all the installation problems i have.

Asim Hussain
e: asim@jawache.net
w: www.jawache.net

Tomasz Sowinski3-Sep-02 1:02

3-Sep-02 1:02

Jawache wrote:
Is this an issue with the Archive vs the DLL

I'm not sure what are you talking about here. By 'archive' you mean 'static library' or something else?

Your app is single .exe, or you have .exe and your own .dlls? Are you using 3rd party libraries?

Tomasz Sowinski -- http://www.shooltz.com

** Putt knot yore thrust inn spel chequers. **

Jawache3-Sep-02 1:10

Stopping the machine hibernating or going into standby

3-Sep-02 1:10

Yeah i think i know whats going on now.

Yes i am using a third party library thats been dynamicaly linked and i had my application statically linked. So the object code to create the FILE object was staticaly linked in my app. Whereas the code to access the FILE object was in the shared DLL version of the library.

Asim Hussain
e: asim@jawache.net
w: www.jawache.net

Dave Merrifield3-Sep-02 0:01

Dave Merrifield

3-Sep-02 0:01

Hi,

We have an application which connects to a database across a network and
want to prevent machines from hibernating.

We can catch the WM_POWERBROADCAST message and check for the PBT_APMQUERYSUSPEND message in the WParam and display a message. So something like this:-

ON_MESSAGE( WM_POWERBROADCAST, OnHibernate )

LRESULT CMainFrame::OnHibernate(WPARAM WParam, LPARAM LParam)
{
if( WParam == PBT_APMQUERYSUSPEND )
{
AfxMessageBox( _T("About to hibrenate or standby!"), MB_OK );
return BROADCAST_QUERY_DENY ;
}
return WParam;
}

The first time we run the app and select hibernate or suspend it is fine and the message pops up correctly however thereafter the screen goes greyed as usualy on a shutdown and the message is not displayed until I give my application focus. Obviously there is something else I need to do to handle the message.

Any suggestions?

Thanks

Dave

Re: Stopping the machine hibernating or going into standby

Tomasz Sowinski3-Sep-02 0:19

Re: Stopping the machine hibernating or going into standby

3-Sep-02 0:19

From MSDN docs on PBT_APMQUERYSUSPEND:

lParam: A DWORD value that specifies action flags. If bit 0 is 1, the application can prompt the user for directions on how to prepare for the suspension; otherwise, the application must prepare without user interaction. All other bit values are reserved

...

The system allows approximately 20 seconds for an application to remove the WM_POWERBROADCAST message that is sending the PBT_APMQUERYSUSPEND event from the application's message queue. If an application does not remove the message from its queue in less then 20 seconds, the system will assume that the application is in a non-responsive state, and that the application agrees to the sleep request

Maybe you should check this lParam bit?

Tomasz Sowinski -- http://www.shooltz.com

** Putt knot yore thrust inn spel chequers. **

Dave Merrifield3-Sep-02 3:54

Dave Merrifield

3-Sep-02 3:54

Thanks,

I had tried checking that bit and only displaying the message then but made no difference.

But now have found the problem is due to showing the warning message box as part of the message handler. If I process the message first and return BROADCAST_QUERY_DENY and then display my message box it all works fine Smile | :)

Dave

Re: Stopping the machine hibernating or going into standby

Tomasz Sowinski3-Sep-02 3:58

Re: Stopping the machine hibernating or going into standby

3-Sep-02 3:58

Dave Merrifield wrote:
If I process the message first and return BROADCAST_QUERY_DENY and then display my message box it all works fine

It makes perfect sense, since you have only 20 seconds to process the message. If user doesn't close the msgbox quite fast, Windows will ignore returned value.

Tomasz Sowinski -- http://www.shooltz.com

** Putt knot yore thrust inn spel chequers. **

Dave Merrifield3-Sep-02 4:02

Dave Merrifield

3-Sep-02 4:02

Yep does make sense now it was when you reminded me of the 20 second time limit it occured to me.

Thanks for your help Tomasz.

Dave

#pragma code_seg

-Dy2-Sep-02 23:56

-Dy

2-Sep-02 23:56

I've spotted this in one of the files I'm maintaining:

#ifdef AFX_COLL_SEG
#pragma code_seg(AFX_COLL_SEG)
#endif

A quick look on MSDN tells me that the code_seg part "specifies a code section where functions are to be allocated". What does that actually mean, what's happening here? MSDN also says I can reset allocation with #pragma code_seg() - do I need to do this, as it's not allready done? Confused | :confused:

Dylan Kenneally
London, UK

Re: #pragma code_seg

Tomasz Sowinski3-Sep-02 0:09

Can I override CEdit to show text in many color.

3-Sep-02 0:09

Comments in MFC source (afxver_.h) suggest that this is 'swap tuning'. Using code_seg changes the ordering of the functions in resulting executable; by placing commonly used functions together you may get some performance boost.

Tomasz Sowinski -- http://www.shooltz.com

** Putt knot yore thrust inn spel chequers. **

Re: #pragma code_seg

Mike Nordell4-Sep-02 0:04

Mike Nordell

4-Sep-02 0:04

Read up on the PE format (knowing MS COFF a bit couldn't hurt either).

What it in practice means is that for a "normal" program your code is located in the PE section ".text", and this pragma changes it to something else.

sonshiro2-Sep-02 23:03

sonshiro

2-Sep-02 23:03

I want to create an auto-complete edit control. The text that user keydown and the text that automatically appear at end have difference color.
How can I override CEdit to print characters in difference color in the same edit control?

Re: Can I override CEdit to show text in many color.

Tomasz Sowinski2-Sep-02 23:20