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Carl Cioffi wrote: I don't really see it as a valid race condition.
Given the context in which you've shown it, it's impossible to say. A race condition is when two logic paths race to be the first to influence the output. What you've shown is simply a function call.
"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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Well, it's a windows service that creates a number of mutexes and then create several listener threads that listen for credit/debit/gift card transactions. I assume the mutexes are used to lock the threads while a transaction is being processed. Given the scenario, I see the mutex creation is performed when the windows service is first started so I just don't see how a race condition could occur unless the service tried to start up twice concurrently. The following function is called once at the startup of the service. I just don't see it. It's a service waiting for a message on a specific port and just sits there and spins until such time. It never tries to execute any of the doscreatemutexsem functions after that.
void InitDebit() {
int rc;
Log(DEBUG_ALWAYS,"Initializing US Debit");
rc = DosCreateMutexSem(FingerPrintSemaphoreName,&FingerPrintSemaphoreHandle,0,0);
if (rc) {
Log(DEBUG_ERROR,"FingerPrint DosCreateMutexSem %d",rc);
}
}
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Hi, dear all,
I have a MFC program which do some calculation, store in a file, then plot the results to a graphic on dialog.
Now I have another program which only want to use the calculation result stored in file from above MFC program but don't want to show the dialog, how can I do it?
I modify the codes in InitInstance() as below:
m_pMainWnd->ShowWindow(SW_HIDE);
m_pMainWnd->UpdateWindow();
return FALSE;
the dialog is not shown, but user still can see the dialog flush before hiding, how can I avoid it?
Thanks!
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Maybe you could give the window zero width and height before it's shown.
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Alan,
Thank you for yoru reply.
In PreCreateWindow(CREATESTRUCT& cs)
I set:
cs.cy = 0.0;
cs.cx = 0.0;
cs.y = 0;
cs.x = 0;
return CFormView::PreCreateWindow(cs);
But there still have flush of the dialog.
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Hmm... Maybe you could try: ShowWindow(SW_MINIMIZE);
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I try it, but you can see the process that the dialog is minimized, that's not what I expected.
Thanks!
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Take the calculation code and move it to a separate source file so you can add it to different projects.
Veni, vidi, abiit domum
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Richard,
Thanks for reply. the existing program is used by several projects, soome want the dialog, some not. so I just want to pass a argument to indicate show dialog or not.
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OK, so accept a parameter and if it's false do not show the dialog, something like:
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR pszCmdLine, int nCmdShow )
{
BOOL myParameter;
if (myParameter == TRUE)
{
DialogBoxParam(hInstance,
MAKEINTRESOURCE(IDD_DLG),
NULL,
(DLGPROC)DlgProc,
NULL
);
}
else
{
}
return TRUE;
}
Where is the problem?
Veni, vidi, abiit domum
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Following Richard's idea , if you program based on MFC Dialog , I think you can change InitialInstance() like this
...........
BOOL myParameter;
CMFCApplication4Dlg *pMainWnd = new CMFCApplication4Dlg;
if(myParameter) {
pMainWnd->DoModal();
}else { pMainWnd->CreateEx(NULL,_T("STATIC"), L"Hi", WS_BORDER , CRect(-15, -15, -15, -15), NULL,NULL);
}
........
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I wouldn't create the main window at all if no Dialog/MainFrame is needed. Just call the class doing the processing from InitInstance(), if no window is requested. The program will end automatically when the processing is complete.
In case of the windowed mode you can start the same processing from a button click or menu item click.
The good thing about pessimism is, that you are always either right or pleasently surprised.
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Hi, dear all,
I solve this issue, thanks for all of you for your help.
inside InitInstance() function
m_nCmdShow = SW_HIDE;
CCommandLineInfo cmdInfo;
ParseCommandLine(cmdInfo);
.........
.......
.......
m_pMainWnd->ShowWindow(m_nCmdShow);
m_pMainWnd->UpdateWindow();
return FALSE;
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It seems no different compared with your original version. why it works？
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Andraw111 wrote:
Now I have another program which only want to use the calculation result stored in file
Then why are you creating such overhead by making it an MFC app? Why not just create a console app with a hidden window? My guess would be 10-15 lines of code within main().
"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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Hi,
I am a newbie in regard to modbus protocol.
I would like to make a communication between two MFC dialog application in VC++ using Modbus protocol.
Can somebody help me with a sample code of this .
I had been browsing for this for the past 4 days and I am lost..
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Member 9990608 wrote: Can somebody help me with a sample code of this .
Most unlikely, you are expected to write your own. You probably need to spend some time looking through some of these links[^] to gain a good understanding of the protocol.
Veni, vidi, abiit domum
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MODBUS is actually a simple protocol, it shouldn't be too difficult for you to deal with it.
Two of the documents linked by Richard were enough for me, namely:
Modicon Modbus Protocol Reference Guide[^] where you may find reference documentations and, above all, the source code of the MODBUS CRC16 algorithm (see Appendix C at the very end of the document).
and
MODBUS APPLICATION PROTOCOL SPECIFICATION V1.1b[^] where you may find a somewhat cleaner explanation of the MODBUS functions.
Veni, vidi, vici.
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can we make websites with c++ or do we really need knowledge regarding javascrpt and HTML5 ?
can we make apps in windows store with c++ or do we really need knowledge regarding c# and HTML5 ?
can we make apps in istore with c++ or do we need knowledge regarding cocoa programming ?
in iTunes-U, windows virtual academy, and many other online courses do not provide training in the feild of c++ ? why ?
is it sooo outdated and useless ?
why is it being devalued ?
is it still " all powerfull " or " just another programming launguage " ?
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Please do not cross post. You have already posted this in QA, here[^]
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Hello all,
I created a MFC dialog using CDHtmlDialog and added a HTML page with many controls and one of them is a IMAGE tag. I got a default image loaded from the hard drive displayed in the HTML page. Up to this part, everything works fine.
Now what i want to do is, dynamically change the image based on the user click on one of the HTML buttons. I don't want this image source to be hard coded in the HTML nor the image source send from the MFC app.
What i want is for the MFC app to send the image data to the HTML in some (binary) format and then the page to display the image.
The possible option i was thinking of was to read the image file which is already in my hard drive as a binary file and send the binary data across to the HTML as a memory buffer, and then use JavaScript to decrypt this binary data and display the image.
I am not even sure whether this is possible. So basically what i want is for the HTML page to display a image from the memory.
Can anyone guide me on how to do this? What approach needs to be taken?
Thanks in advance.
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This is the same issue as all your other questions in this forum. Perhaps you should try some of the suggestions you have already been given.
Veni, vidi, abiit domum
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Don Guy wrote: What approach needs to be taken?
What you're supposed to do is respond to the button click by generating new HTML on the fly, and telling the HtmlDialog to load it. I don't recall the exact function names, but you'll find it all in the documentation.
The difficult we do right away...
...the impossible takes slightly longer.
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To make the question much more simpler 
1. Can i pass the Image file (JPG, PNG) as a memory buffer like "unsigned char *" from my MFC app to the HTML page and then use some JavaScript function to understand that it's a Image file and display on the HTML page. It can be done either by passing the JPG to the "src" of Image or drawing it on a CANVAS. But all JS/HTML should have is a memory buffer of Image file.
So the 1st question is,
1. How to read a Image file as memory buffer (unsigned char *) in MFC? i.e, making sure it doesn't loose any NULL terminators or any binary contents.
And 2nd question is,
1. How to pass this memory buffer to the JavaScript function in the HTML page?
And 3rd question is,
1. How can the JavaScript function decrypt this memory buffer into a Image file and display in the HTML page?
The reason why i want to do it this way is because the HTML should never be able to display the Image file from a file path or URL. That is a requirement for the project i am doing.
HTML page should only use a memory buffer containing the Image file info. Hope this information helps.
Thanks in advance. I appreciate the 2 earlier responses i got.
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