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No. This is existing code and I was just curious if I was allowed to do that or not. I thought I could but couldn't find anything out there to confirm that it would work correctly.
I will look up Unions, though, for future reference.
Thank you.
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ChemmieBro wrote: No. This is existing code
You still can use union in the existing code! And you won't even need to cast.
ChemmieBro wrote: I thought I could but couldn't find anything out there to confirm that it would work correctly.
You have the debugger of VC++ for you to watch the memory addresses and the values.
Maxwell Chen
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Maxwell Chen wrote: You still can use union in the existing code!
Except for the swapping of byte order (if I read the original code correctly).
Mark
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/coffee.gif)
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Another way is...
int nNum = 10;
char Data[4] = {0};
memcpy(&Data, &nNum, 4);
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I'm using VC++ 6 service pack 6 on Windows 2000. I'm working with an automation server MDI application with the following requirements.
1) Can be started by user with visible interface.
2) Only one instance at a time.
3) If controlled by client, runs in background (invisible) initially.
4) Client(s) has option to make application visible.
5) If visible and user attempts to close with client(s) connections, warning is given with choice to close or not.
6) Has menu item that allows user to disconnect from all clients.
7) If invisible, closes when last client disconnects.
I have no problem with 1-4, the questions arise with 5-7. In order to implement these, the server needs to know if there are clients connected to it. My main automation class (CAutoApp) is instantiated every time a client contacts it. In the constructor I add to a static array of LPUNKOWNs (m_lpUnk[MAXNUMCONN]) using GetInterface(&IID_IUnknown):
LPUNKNOWN CAutoApp::m_lpUnk[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
CAutoApp::CAutoApp()
{
EnableAutomation();
for (int i=0; i < MAXNUMCONN && NULL != m_lpUnk[i]; i++);
if (i < MAXNUMCONN)
m_lpUnk[i] = GetInterface(&IID_IUnknown);
}
Whenever a client closes, CMainFrame::OnClose is called in the server. So I have the following code to implement 5 and 7 in OnClose():
int i=0;
while(i < MAXNUMCONN && NULL != CAutoApp::m_lpUnk[i])
{
try
{
CAutoApp::m_lpUnk[i]->AddRef();
CAutoApp::m_lpUnk[i++]->Release();
}
catch(...)
{
for(int j=i; j<MAXNUMCONN-1 && NULL != CAutoApp::m_lpUnk[j]; j++)
CAutoApp::m_lpUnk[j] = CAutoApp::m_lpUnk[j+1];
}
}
if (NULL != CAutoApp::m_lpUnk[0])
{
if (IsWindowVisible())
{
if (IDNO == AfxMessageBox("One or more remote connections is still active. Exit anyway?", MB_YESNO))
return;
}
else
return;
}
.....
CMDIFrameWnd::OnClose();
This works, although maybe it's a no-no to use a try-catch this way. If there's a better way to do it, I'd like to know.
To implement (6), I have the following:
void CMainFrame::OnCloseconnections()
{
if (IDNO == AfxMessageBox("This will close all connections. Are you sure?", MB_YESNO))
return;
for (int i=0; NULL != CAutoApp::m_lpUnk[i]; i++)
{
try
{
while(CAutoApp::m_lpUnk[i]->Release());
}
catch(...)
{
}
CAutoApp::m_lpUnk[i] = 0;
}
}
This works, however when a user attempts to close my application, it crashes somewhere in the OLE dlls. There must be a better way to do what I'm trying to do?
Thanks,
Gary
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I have a program that reads contents of a text file. There is this one Swedish word that gives me trouble. The word is KALVFÄRS. When my program reads, read buffer contains KALVFÄRS, which is different than what's in the file. But the word is shown correctly in EditPlus. I need my program to read the way EditPlus reads.
I first used Win32 api to read, then tried with file io functions (fread) to read. I still have not found a way to read it correctly. Does any one know how EditPlus reads, or is there anything I should try?
BTW, language is set to Swedish in my computer.
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Try to read in binary mode?!
Maxwell Chen
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I already did, but no difference.
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Holy cow, man! Assembly language AND Swedish! You rock 
Mark Salsbery
Microsoft MVP - Visual C++
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Norwegian.
-David Delaune
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Mark Salsbery
Microsoft MVP - Visual C++
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That's just happy Swedish 
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its urgent...............pls.........
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Maximilien wrote: ok.
do we have to work on this??
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You/codeProject$$>
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Emailing your friends directly may get a quicker response.
Isn't there an app wizard in VC6 that makes a text editor application
with a few mouse clicks? A doc-view app (SDI or MDI) with a CEditView
as the view perhaps?
Or did I dream it.
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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Even more mind-boggling is the existence of the source for wordpad in the visual C++ Samples
Judy
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Brilliant!
I think that's what I was remembering (attempting to, anyway) actually!
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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Try using Google.
Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke
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Hi,
We have an application developed using MFC and works fine on windows xp sp2, recently we wanted to try our application on windows vista. When we run the application on windows vista it crashes, and below is the callstack.
7346382d()
user32.dll!_InternalCallWinProc@20() + 0x23 bytes
user32.dll!_UserCallWinProcCheckWow@32() + 0xb3 bytes
user32.dll!_SendMessageWorker@20() + 0xd5 bytes
user32.dll!_SendMessageA@16() + 0x49 bytes
ourdll.dll!CWnd::SendMessageA(unsigned int message=0x00000010, unsigned int wParam=0x00000000, long lParam=0x00000000) Line 42 + 0x20 bytes C++
and here is the extract from eventlog
Faulting application OURAPP.EXE, version 53.8.0.0, time stamp 0x47626d96, faulting module COMCTL32.dll_unloaded, version 0.0.0.0, time stamp 0x4549bcb0, exception code 0xc0000005, fault offset 0x7346382d, process id 0x7374, application start time 0x01c888ff11ea7ee6.
What I could understand from event log is our application is making a call into COMCTL32.dll after somebody has unloaded from our application space (I may be very well wrong). So then I placed InitCommonControls() call in OURAPP.EXE, now it works fine (it doesnt crash). The application works fine on windows xp sp2 even without this InitCommonControls() call.
Just an additional information we dont use any Common Controls in our application except scroll bars (CScrollBar MFC class). Rest all controls are our own developed and are bundled into ourdll.dll
Could someone please help me in understading the above scenario? Thanks in advance
Cheers,
Suresh
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I would guess you must be using something (maybe indirectly) in the common
controls library that wasn't initialized - like the registration of a window
class.
You should be using InitCommonControlsEx() anyway, even if just for the
ICC_STANDARD_CLASSES control classes.
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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Mark,
Thanks for your reply. Yeah we may be very well indirectly using some thing in the common controls library, however what I am trying to understand is why this _crash_ only happens on vista? bcoz it works fine on xp sp2 without any InitCommonControls/InitCommonControlsEx call.
Cheers,
Suresh
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sthotakura wrote: why this _crash_ only happens on vista?
It's a different operating system - different version of control libraries, different implementations.
You may have just got lucky on XP...There may be a bug in your code...there may be a bug in Vista.
If you can reproduce the crash consistently, then you should be able to debug it with better detail than just
a stack dump.
There's a lot of unknown possibilities here, but there should be nothing wrong with a call to InitCommonControlsEx(),
especially if you need it
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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