Resource Access in Multiple Timers in Single thread - C / C++ / MFC Discussion Boards

Toni7817-Jun-03 19:17

17-Jun-03 19:17

Michael Dunn wrote:
Stop whatever you're doing and install SP 5. I've seen VC be flaky with its compiles on 2K and XP (the dreaded internal compiler error on perfectly normal code) in the pre-SP5 builds.

I couldn't agree more. I had the exact same problem with VS6 before I installed SP5.

// Afterall, I realized that even my comment lines have bugs

Multi-line listctrl

pranavamhari17-Jun-03 4:51

pranavamhari

17-Jun-03 4:51

Hi all,

I would like to have a listctrl with multiline support. ie, each report (entry) can have mulitple lines.
how can i do that? any links ?

thanks in advance
hari

Hari Krishnan

Re: Multi-line listctrl

Iain Clarke, Warrior Programmer17-Jun-03 5:20

Iain Clarke, Warrior Programmer

17-Jun-03 5:20

Just a quick hunt gives:
Editable Multi-line ListBox[^]
Multistring List Control[^] and
Changing Row Height in an owner drawn Control[^]

why may be of use to you.

Iain.

Accelerator stored in DLL

SD317-Jun-03 4:03

SD3

17-Jun-03 4:03

I want to load the Accelerator that I have stored in a DLL in the EXE that link it. So I can, for example, press the Accelerator "F1" stored in the DLL and answer to the relative message in the EXE. Is it possible ?
Thank you for any answer.
Andrea

Re: Accelerator stored in DLL

basementman17-Jun-03 5:25

basementman

17-Jun-03 5:25

You can do *anything*. Some ideas on your particular problem include:

In your app init instance, load the dll(s) and extract the custom accelerator tables into a variable (or list, as appropriate).

Override the CWinApp::PreTranslateMessage(). In that handler, call TranslateAccelerator, passing the handle to your custom accelerator table. If you have more than one custom accelerator table, iterate through your list, calling TranslateAccelerator() until either your list members are exhausted or TranslateAccelerator returns non-zero. If TranslateAccelerator() returns non-zero, break and return TRUE from the PreTranslateMessage(). If your list is exhausted before PreTranslateMessage() returns a non-zero value, call the base (CWinApp::PreTranslateMessage()).

Example:

member: CPtrList m_oCustomAcceleratorList;<br />
<br />
BOOL CMyApp::InitInstance()<br />
{<br />
  LoadDLLAcceleratorTables(&m_oCustomAcceleratorList);<br />
  // loads dlls and calls dll function that <br />
  // does a ::LoadAccelerators(), storing returned handle<br />
  // in the list<br />
}<br />
<br />
BOOL CMyApp::PreTranslateMessage(MSG *pMsg)<br />
{<br />
  HACCEL hAccel;<br />
  POSITION pPos = m_oCustomAcceleratorList.GetHeadPosition();<br />
  while (pPos)<br />
    {<br />
      hAccel = (HACCEL)m_oCustomAcceleratorList.GetNext(pPos);<br />
      if (hAccel)<br />
        {<br />
          if (::TranslateAccelerator(m_pMainWnd->GetSafeHwnd(),hAccel,pMsg))<br />
            return TRUE;<br />
    }<br />
<br />
  return CWinApp::PreTranslateMessage(pMsg);<br />
}

onwards and upwards...

Re: Accelerator stored in DLL

SD318-Jun-03 2:36

SD3

18-Jun-03 2:36

Thank you very much basementman, I tried and it works. It's perfect for my problem.
Thanks a lot
Andrea

Re: Accelerator stored in DLL

Iain Clarke, Warrior Programmer17-Jun-03 5:46

Iain Clarke, Warrior Programmer

17-Jun-03 5:46

You can replace CFrameWnd::m_hAccelTable (AfxGetMainWnd ()) with whatever
accelerator you want.

So you can load the accelerator from a dll, then assign it as above.

Iain.

ps. Look up LoadAccelerator, AfxFindResource.

Resource Access in Multiple Timers in Single thread

RCM17-Jun-03 4:03

RCM

17-Jun-03 4:03

Hi,
I have a dialog based MFC application which has 2 timers with same interval (say 5 mins) accessing a single resource. A structure instance which is a member variable of the App class is being updated in one timer and the same structure instance is being used in another timer. ( Typically, the memory resource is being accessed for write in one timer callback and for read in another timer callback ). The code snippet something is like this,

CMyFrameDlg::TimerCallback1(...)
{
...
theApp.m_Struct.nVar1 = 10;
theApp.m_Struct.szVar2 = "test";
...
...
}

CMyFrameDlg::TimerCallback2(...)
{
...
...
localnVar = theApp.m_Struct.nVar1;
localszVar = theApp.m_Struct.szVar2;
...
}
The 2 timers get called simultaneously. Issue is, that the values dont get reflected properly in timer2 and while the struct is being accessed in timer2 it is being updated simulataneously in timer1. Both timers belong to the same Thread.

1.) I need to update the same resource in one timer and use it for some other purpose in the second timer. Is it possible ?

2.) I also have certain WM_.. messages posted from another thread to this thread on which a callback gets invoked. And this callback also accesses the same structure instance, but the values are not properly updated. Why is it so ?

Point is.. accessing the same resource ( memory) in multiple timers of the same thread. And also accessing same resource in multiple callbacks of the same thread (like user defined WM_message callbacks). Is there any restriction or way to do that ?

Anxiously Waiting for a reply Unsure | :~

Cheers

Raja

Re: Resource Access in Multiple Timers in Single thread

Harsha Gopal17-Jun-03 5:21

Harsha Gopal

17-Jun-03 5:21

Raja,
Why dont you consider using the Critical Section to avoid simultaneous access to the same resource... So, when the timers get called simultaneously, only one timer accesses the resource and the other waits till the critical section is released. If the application spans processes, you should be considering Mutex... Hope it helps you...

Harsha
----------------------------------
http://www.ece.arizona.edu/~hpg
----------------------------------

Re: Resource Access in Multiple Timers in Single thread

harish kota17-Jun-03 18:41

harish kota

17-Jun-03 18:41

hi Harsha

Critical section can be used only when resource is getting accessed between 2 threads. What raja needs a way to share resource within same thread.

Re: Resource Access in Multiple Timers in Single thread

RCM17-Jun-03 20:09

RCM

17-Jun-03 20:09

Thanks for your reply. I would like to know if critical sections can be
used to lock a section of code within the same thread. Critical Sections within same thread - possible ?

Cheers

Raja

Re: Resource Access in Multiple Timers in Single thread

Harsha Gopal18-Jun-03 6:08

Harsha Gopal

18-Jun-03 6:08

I am sorry that I misunderstood the question... Anyway, I think critical sections can be used within the same thread. Although developed for multithreading, I suppose that critical sections do not understand which thread they should give access; they just know which resource to lock.

Harsha
----------------------------------
http://www.ece.arizona.edu/~hpg
----------------------------------

about message reflexion ...

Maximilien17-Jun-03 3:58

Maximilien

17-Jun-03 3:58

I have a slider control (from http://www.codeproject.com/editctrl/smartedit.asp) in a dialog, I want to receive notification in the dialog.

now, the HScroll and VScroll are handled in the slider class with ON_WM_HSCROLL_REFLECT and ON_WM_VSCROLL_REFLECT, which, as far as I understand, will override the message from the dialog ( ON_WM_VSCROLL and ON_WM_HSCROLL ).

Is there a way to let the message percolate to the dialog, as well as the control itself ?

I read the technical note TN062, and I'm not sure I understand correctly how this works.

Can I replace the WM_VSCROLL and WM_HSCROLL messages with WM_NOTIFY_EX ?

Thanks.

Maximilien Lincourt
For success one must aquire one's self

Re: about message reflexion ...

Ryan Binns17-Jun-03 4:13

Ryan Binns

17-Jun-03 4:13

Message reflection does not influence normal message behaviour. Your dialog can handle WM_HSCROLL and WM_VSCROLL with no problems at all. Just handle them exactly as usual (ON_WM_VSCROLL() etc.)

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

Breakpoint with condition?

Brian van der Beek17-Jun-03 3:17

Brian van der Beek

17-Jun-03 3:17

I'm trying to set a breakpoint with a condition, but without success. What I need is a condition with a CString, however the following expression does not work:

<br />
m_name == "my name"<br />

Is this even possible, or am I doing someting wrong?

Re: Breakpoint with condition?

Maximilien17-Jun-03 3:38

Maximilien

17-Jun-03 3:38

can you modify the Code ?

if so, put an ASSERT in the code where you want to check for the condition.

Maximilien Lincourt
For success one must aquire one's self

Re: Breakpoint with condition?

Brian van der Beek17-Jun-03 3:44

Brian van der Beek

17-Jun-03 3:44

I could do that, but I was wondering if it was possible to set the breakpoint condition this way.

Re: Breakpoint with condition?

peterchen17-Jun-03 3:46

peterchen

17-Jun-03 3:46

you can set conditional breakpoints only on intrinsic comparisons.
The best you can do is bool b = m_name == "name"; and set a bp on the next line with the condition b==true

"Der Geist des Kriegers ist erwacht / Ich hab die Macht" StS

sighist | Agile Programming | doxygen

Oracle Form or Report from a Visual c++

Felix_br17-Jun-03 3:09

Felix_br

17-Jun-03 3:09

Hi,

How can I call an Oracle Form or Report from a Visual c++ application ?

Thanks in advance

Felix

please help! fast simple question

wickedclownz17-Jun-03 2:29

wickedclownz

17-Jun-03 2:29

I'm including the dos.h header with this source.. I can't compile his. I have compiled this on my old computer without any problems... when i had windows 98... but now I have windows XP and I cant compile this. Im using Dev-C++.. can someone tell me how I can compile this simple program on windows XP? I'm just trying to call BIOS to change the VGA mode

int main( )
{
union REGS regs;
{

regs.h.ah = 0x00;
regs.h.al = 0x13; //enter VGA mode 13h
int86(0x10,& regs,& regs);
};
getch();

union REGS regs;
{
regs.h.ah = 0x00;
regs.h.al = 0x02; //back to text mode
int86(0x10,& regs,& regs);
};
return 0;
}

Re: please help! fast simple question

WoutL17-Jun-03 2:35

WoutL

17-Jun-03 2:35

Sorry,

But you cannot communicate with the hardware directly under WindowsXP.

Re: please help! fast simple question

WoutL17-Jun-03 2:59

WoutL

17-Jun-03 2:59

Yas, you're right. As long as he is using the same compiler version??? I don't think 'newer header files' will contain function prototypes to int86. Confused | :confused:

Re: please help! fast simple question

David Crow17-Jun-03 2:54

David Crow

17-Jun-03 2:54

The REGS union is for old DOS programs. Newer 32-bit compilers do not support it. You'll need Visual C++ v1.52c for this.

ok thanks, what about this?

wickedclownz17-Jun-03 11:35

wickedclownz

17-Jun-03 11:35

Well the main reason I wanted to call BIOS was so I can control the X and Y position inside text mode. (0x02). Is there any other way I can do this without calling BIOS?

Re: ok thanks, what about this?

David Crow18-Jun-03 2:52

David Crow

18-Jun-03 2:52

Try SetConsoleCursorPosition().

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.