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That may well be true but it does not seem to be the way OP is implementing it. I'm ready to stand corrected, however.
Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman
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I could be completely wrong on this, but to me, it appears that he has defined a variable, something like CListCtrl m_ListDrive in the CRecoverDriveDlg class.
He is expecting this variable to automatically attach to some list control he has in the dialog template (I dont see a call to m_ListDrive.Create()).
My suggestion was to manually attach m_ListDrive to this control somehow.
It is possible that he has called m_ListDrive.Create() elsewhere in his code and simply hasn't shown it and hence I am completely wrong. Since the original issue is m_ListDrive is NULL, then this call has failed, and that code would be relevant to helping him find a solution.
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I agree, which is why my question to him was "what is this variable and where is it initialised?". We will see; or not!
Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman
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Why shouldn't it be NULL?
I mean, you didn't show us the code initializing it.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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As I know IOCP which is called one powerful model to meet socket program in scalable case, from then on I have a question on IOCP.Today, still puzzle me.
The question is What will happen if you post more than one WSASend() request in one client socket which has been associated with the existing completion port. The scenario is as follows:
IO Request:
WSASend(...,wsaBuff1,1,...); WSASend(...,wsaBuff2,1,...); WSASend(...,wsaBuff3,1,...);
What will happen in the completion port?
1/ How many completion packet will be received?
2/ What is the order of the completion packet?
3/ Is it possbile to require more than one send request for each buffer? It means one time send request can't finish the data transmission. The user need to post another or more WSASend request for the rest data.
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SAMZCN wrote: How many completion packet will be received?
One for each WSASend call. Always one for each completion packet queued.
SAMZCN wrote: What is the order of the completion packet?
If you only have one completion handler thread then they'll be in order queued. Multiple completion handler threads could execute in any order as always.
SAMZCN wrote: Is it possbile to require more than one send request for each buffer?
Yes it's possible, so you need to check if the entire buffer of data was sent for each call, same as always with sockets.
Note: If you make multiple asynchronous WSASend calls using an I/O completion port then make sure all calls are made on the same thread.
For TCP/IP, I personally much prefer only one outstanding read and/or one outstanding write per socket given the above information 
Mark Salsbery
![Java | [Coffee]](https://www.codeproject.com/script/Forums/Images/coffee.gif)
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Hello Mark,
Much appreciated for your input. I think it is very helpful to me.
Mark Salsbery wrote: SAMZCN wrote: Is it possbile to require more than one send request for each buffer?
Yes it's possible, so you need to check if the entire buffer of data was sent for each call, same as always with sockets.
Note: If you make multiple asynchronous WSASend calls using an I/O completion port then make sure all calls are made on the same thread.
For TCP/IP, I personally much prefer only one outstanding read and/or one outstanding write per socket given the above information
At this point, it is the biggest puzzling thing to me. I read many articles on this issue about IOCP. But don't find any conclusion to make me convienced. By your saying, it seems really I need to check the whether the entire buffer in one request was sent out completely. If not, I need to post another send request for the rest data.
Yes. Really I want to make multiple asynchronous WSASend calls using an I/O completion port to get performance improvement. But I can't make sure the calls are received by same thread. It is my problem. I do many trials on this. It seems meaningless.
I agree that one outstanding IO operation per socket in a given time is a good way to get stable running. Thanks.
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SAMZCN wrote: it seems really I need to check the whether the entire buffer in one request was sent out completely. If not, I need to post another send request for the rest data.
With TCP/IP protocol, YES - always with sockets! (I say with TCP/IP since for example, UDP datagrams always go all at once).
SAMZCN wrote: I want to make multiple asynchronous WSASend calls using an I/O completion port to get performance improvement. But I can't make sure the calls are received by same thread.
Won't really be any performance increase.. The network stack (including the socket and the network adapter(s)) is a huge bottleneck and generally magnitudes slower than your running code.
*edit* Plus you really can't since you need the result of the previous sends. Any thread synchronization you could maybe add to "solve" this would probably just slow down the IOCP since you'd have IOCP completion handler threads waiting on synch objects instead of waiting for completion packets so overall performance could suffer when many sockets are involved (which is where IOCPs really shine).
Mark Salsbery
modified 26-Oct-11 14:26pm.
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Hi Mark. Thanks.
Appreciated for your share. It really helps me understand IOCP and other asnc IO operation.
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I have an SDI app, where I want to serialize an versionable object, of CData class :
class CData : public CObject
{
DECLARE_SERIAL(CData)
public:
CData();
virtual ~CData();
virtual void Serialize(CArchive& ar);
BOOL ReadDocumentFromDisk();
BOOL WriteDocumentToDisk();
};
and here is implementation code :
IMPLEMENT_SERIAL(CData, CObject, VERSIONABLE_SCHEMA | 1)
CData::CData()
{
}
CData::~CData()
{
}
void CData::Serialize(CArchive& ar)
{
CObject::Serialize(ar);
try
{
if(ar.IsLoading())
{
TRACE("Loading : objectschema - %d\n",ar.GetObjectSchema());
int n = 0;
ar >> n;
TRACE("n is %d\n",n);
}
else {
int x = 456;
ar << x;
}
}
catch(CFileException* pFileException)
{
pFileException->ReportError();
pFileException->Delete();
}
}
BOOL CData::ReadDocumentFromDisk()
{
CFile file;
CString sFile;
CFileException FileException;
::GetModuleFileName(NULL,sFile.GetBuffer(255),255);
sFile.ReleaseBuffer();
sFile = sFile.Left(sFile.ReverseFind('\\') + 1);
sFile += _T("Default.tse");
if(! file.Open(sFile,CFile::modeRead,&FileException))
{
return FALSE;
}
CArchive ar(&file,CArchive::load);
Serialize(ar);
return TRUE;
}
BOOL CData::WriteDocumentToDisk()
{
CFile file;
CString sFile;
CFileException* pFileException = NULL;
::GetModuleFileName(NULL,sFile.GetBuffer(255),255);
sFile.ReleaseBuffer();
sFile = sFile.Left(sFile.ReverseFind('\\') + 1);
sFile += _T("Default.tse");
if(! file.Open(sFile,CFile::modeCreate | CFile::modeWrite,pFileException))
{
return FALSE;
}
CArchive ar(&file,CArchive::store);
Serialize(ar);
return TRUE;
}
and from somewhere in CMyView class, I call :
void CTestSerializeView::OnHelpLoad()
{
CData data;
data.ReadDocumentFromDisk();
}
void CTestSerializeView::OnHelpStore()
{
CData data;
data.WriteDocumentToDisk();
}
although serialization of integer variable is good, I always get version -1 of CData object :
<br />
TRACE("Loading : objectschema - %d\n",ar.GetObjectSchema()); <br />
what I'm doing wrong ?
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Debug each step and see where the value is coming from.
==============================
Nothing to say.
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Hello,
I have a class that doesn't connect to a dialog or window
and I need to do some operations on timer but the timers works only with dialogs ,
does anyone know another way I do it?
thank
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You can have a thread running the Sleep API. After a specified interval of time it becomes active, performs it's task and sleep's again for the specified duration.
That is somewhat similar to what a timer does.
You talk about Being HUMAN. I have it in my name
AnsHUMAN
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Thanks for the answer,
But the operations that I need to perform on the timer
shuld have an approach to the data members and member Functions of the class ,
can I do it with threads?
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No, not thread safe at all.
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Could make it threadsafe with Mutexes[^]
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Yeah but consider what he wants to do... if he's already using the WinAPI, might as well use the Win timers. Otherwise we'll have to answer a bunch of questions regarding mutexes next [joke  ].
modified 25-Oct-11 16:28pm.
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Just use the win 32 set timer method: http://msdn.microsoft.com/en-us/library/windows/desktop/ms644906(v=vs.85).aspx[^]
Dont forget, MFC just wraps the Win32 API, and even then not all of it (there is a lot of rich unctionality there not available in MFC), and pretty much all MFC functions have a function of the same name in the win32API.
Most of these win32 funcs take a window handle as the first param, and thats generally the only difference between them, and their MFC counterpart, since the MFC one generally calls itself.
So for example the win32 MessageBox() func has a HWND as the first partam, then all the rest are the same as MFC.
You can also call the win32API directly form MFC code. Just use the global namespce operator :: before each call ie:
::MessageBox(hWnd, txt, msg, MB_OK);
You can get window handles for other processes/wondows easilly too. FindWindow() returns a HWND. Its params are eityher the class of the window, or its text (in the title bar).
You can use this to send or post messages, such as WM_COMMAND ones to another window.
Like I say, there is a lot you can do outside of MFC. (Window hooks are particularly interesting things. Very very powerfull.)
==============================
Nothing to say.
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Thanks a lot,
As I understand I need to use SetTimer() and to give it an handle to window but
the class is not connected to a dialog so what the hWnd that I need to pass?
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Timers have nothing to do with dialogs, they operate on any Window. The issue of passing a handle to the window is so that the Windows framework knows where to post the WM_TIMER message that gets raised when the timer expires. If you do not have a Window to connect the timer to then SetWaitableTimer()[^] may be able to help you.
Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman
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aangerma wrote: so what the hWnd that I need to pass?
The one to your dialog/app window that handles WM_TIMER.
As suggested you can get this handle with a FindWindow() specifying the title text. Or you can provide it form the fialog itself, I forget the func, something like GetSafeHwnd() or some such, but there is one for a dialog to get its own handle.
Like I say, hunt through the win32 API. You will find what you need there.
==============================
Nothing to say.
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SetTimer[^] has a fourth parameter, an application defined callback function. Use that and set the HWND to NULL.
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He might find that difficult to specify a class member as a call back function. But yes, it is doable (and one of the reasons I prefer C, OK, you need to be a good programmer, but you can do what you want)
==============================
Nothing to say.
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Now why didn't I think of that; good answer.
Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman
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