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No, do not use Ping and do not rely on running it in OnIdle(), you should use a timer.
There are several ways a TCP link can "break" without both sides being properly notified, especially over the Internet, but even on a LAN. If it is important to you to have reliable, persistent links and you have control over the server side code, I suggest you define a keep-alive mechanism.
There are many, many ways of doing this. Over the years I have found the following approach to be sufficient just about anywhere I use persistent TCP connections.
- Determine which side will be sending data the most. Let's call that side A, the other side is side B. Depending on the nature of your applications, side A can be either the server or the client.
- Determine the maximum time a link can be down before reacting to it - 1 second, 10 seconds, 30 seconds, etc. Let's call that T. You do not want to flood the network with these messages, so go as high as you can.
While connected:
- Side A must keep track of the last time a message (data or keep-alive) was sent. If more than T/3 seconds have passed since a message was sent, send a keep-alive message. If the link has gone down, the socket send operation will fail and the program has to react to it.
- Side B must keep track of the last time a message (data or keep-alive) was received. If more than T seconds have passed since a message was received, consider the link down and react to it.
Soren Madsen
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what is operator overloading and how it works with code.
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it refers to providing additional meaning to normal c++ operators when they are applied to user defined data types
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I want into MDI application to open an menu item on OnLButtonDblClk on client zone in CMainFrame ... so I mapped CMainFrame::OnLButtonDblClk :
void CMainFrame::OnLButtonDblClk(UINT nFlags, CPoint point)
{
TRACE("OnLButtonDblClk\n");
CMDIFrameWnd::OnLButtonDblClk(nFlags, point);
}
but I had an suprise ! I didn't see any TRACE on my doubleclick ... why ?
modified 21-Feb-13 4:54am.
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It's a long time since I did any MFC but do you need to add something to your message map?
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The wizzard did that :
BEGIN_MESSAGE_MAP(CMainFrame, CMDIFrameWnd)
ON_WM_LBUTTONDBLCLK()
END_MESSAGE_MAP()
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Well, as I said, it's been a long time, but I always found the wizard code tended to work 'out of the box', so I cannot see why it would not call the connected function as expected.
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That's why seems to me weird ... I only want to do something on double-click on client area of mainframe ...
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You could try checking with your debugger that your window class fulfils the requirements specified here[^]. Other than that, lots of breakpoints and single stepping through code seems to be the path you must follow.
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The client area consists of the view.
That's the reason why the control flow does not enter the OnLButtonDblClk handler of the frame class.
You will need to create a handler for OnLButtonDblClk in the view class.
However, you can create a handler for OnNcLButtonDblClk in the frame class where the double click on an area outside the view will be handled like the edges of the window, title bar, menu bar etc.
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I try that, and does function where you said : menu area, etc. ... I need to know if the user fire double-click between those areas ... right near client area, I mean in dark area of CMainFrame ...
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I don't think you will get double click messeages in the dark area.
You will however be able to trap the WM_LBUTTONDOWN message in the PreTranslateMessage override in the main frame class.
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Good ideea, I will try tomorow ... thank you.
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I try in follow way :
BOOL CMainFrame::PreTranslateMessage(MSG* pMsg)
{
if(pMsg->message == WM_LBUTTONDBLCLK)TRACE("OnDblClick - PreTranslateMessage\n");
return CMDIFrameWnd::PreTranslateMessage(pMsg);
}
but I don't see any traces when I double-click on darrk area of mainframe ... only in CView client area ...
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As I said in my previous message, you will only be able to get WM_LBUTTONDOWN messages.
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// client zone of CMainFrame
Please let the Spy++ Tool to confirm your assumption 
(it could be another window)
They sought it with thimbles, they sought it with care;
They pursued it with forks and hope;
They threatened its life with a railway-share;
They charmed it with smiles and soap.
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Hi All,
After reading about parallel programming by multicore processor,I have some doubts.
1>Its undoubtedly best idea for play stations,X-Box [as they have soo... many cores]
But will it prove to be effective for core i7 running 8 parallel process then running 100 thread in Windows 7 64 bit?
2> If some how its managed to make all the process running parallel with less critical resource to then will it give better performance over 100 thread?
3>If not then in which case I can see multicore programming[I am trying VC++ with Opem MP] winning over multi thread in my i7,win 7[64 bit] ,4GB ram?
[it will be great If I can get a code in C++ or JAVA to run in my machine to compare same task running 1>parallel,2>sequence,3>thread]
Eagerly Waiting for the response.
Thanks in advance.
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See here[^]; please post your question in one forum only.
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I am facing problems in launching my dll application. which is launching correctly for some PCS but it is not launching for some other PCS. Pls check the 2 attachments.
one is working.jpeg which is working fine. it is expected that when clicking on launch button from client this should show the screen with the CAD model. for some pcs this is working.
Check the other attachment which not-working-screen-shot.png which on launching the application it's not displaying the model. it is a grey color screen whethe there's no opengl window even.
I have developed this dll application in dialog based window. Pls help resolve this problem. Thanks a lot in advance Sujan
Check the attachements in codeguru. thread name as this thread name "dll application is not launching for some PCS" under VC++ programming.
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What do you mean by "dll application"? You cannot launch a DLL, it can only be loaded from a running executable file. As to your links, if you cannot post them here I do not think anyone is going to go searching for them. Also without some further information than "doesn't work", it's anybody's guess what is happening.
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Richard MacCutchan wrote: . Also without some further information than "doesn't work", it's anybody's guess what is happening.
Come on, Richard. This is exactly why you should stop using Windows 95. It just doesn't have the guessing capability that newer OSs do.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous
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I have a Delphi application which Creates a shared memory uses CreateFileMapping, OpenFileMapping, MapViewOfFile functions.
Now I wanted to share the same memory for my MFC application. I used the OpenFileMapping, MapViewOfFile functions.
I created a structure exactly same in size as the Delphi application and mapped the structure object.
sample code:
HANDLE hMapObject2;
hMapObject2 = OpenFileMapping( FILE_MAP_ALL_ACCESS, FALSE, "PP101U3_SHARED");
if( !hMapObject2 )
{
AfxMessageBox("Failed to open Simpack DataBase");
return( 0 );
}
Simpack = ( struct SIMPACKDB *) MapViewOfFile( hMapObject2, FILE_MAP_ALL_ACCESS, 0, 0, 0 );
if( !Simpack )
{
AfxMessageBox("Failed to create Simpack File Map View");
return(0);
}
Esim->SPV1 = Simpack->SP_Z;I am able to read the values exactly correct for all the member variables in the structure.
But when I try to write value in the shared memory, its not changing. It shows the previous value immediately in the debugger watch window.
The value of Simpack->SP_Z[15] is 0.5010 as read from the shared memory which is got from the Delphi application. i.e., value set by the Delphi application
When I set or write the value of the same variable to the shared memory in my MFC Application using the code:
Simpack->SP_Z[15] = 0.6123;
or
float test = 0.6123;
memcpy( Simpack->SP_Z + 16, &test, sizeof(float));it still shows the previous value 0.5010 which is got from the Delphi Application. But When I change the same variable's value in the Delphi applicationit changes and the changed value can be read here in the MFC application.
Please help me to find why I am unable to write or set value in the shared memory from my MFC Application and suggest me with any code how to write the values in the shared memory from my MFC Application.
Is there anything wrong in the code?
Is this happening because I am sharing the memory that is created by a Delphi Application from a MFC Application? i.e., Sharing memory between Delphi and MFC Application is not allowed.
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