Re: iocompletionport (IOCP) and threads - C / C++ / MFC Discussion Boards

Mark Salsbery15-Oct-08 4:40

15-Oct-08 4:40

An MFC app has to have ONE CWinApp object.

That's by design. Why are you trying to do it differently?

You need a thread running to create another thread Smile | :)

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: Threading error

sriram6518-Dec-08 2:59

sriram65

18-Dec-08 2:59

Sorry for the very very very late reply and thanks a lot now understood

iocompletionport (IOCP) and threads

swjam7-Oct-08 2:49

swjam

7-Oct-08 2:49

questions and statements for (your) confirmation:

* more than one device can be associated to an IOCP
* each device would have its own thread pool
* each thread pool is associated to a particular function. which is why ANY of the threads (although usually the last in) in the pool can be awakened each time there is a new entry in the completion queue.
* somehow IOCP knows which thread in a pool to wake up depending on which IOCP-associated device has a completed IO request.

thanks in advance.

----------------------------------------------------------
"unzip; strip; touch; finger; mount; fsck; more; yes; unmount; sleep" - my daily unix command list

Re: iocompletionport (IOCP) and threads

Mark Salsbery7-Oct-08 4:07

Mark Salsbery

7-Oct-08 4:07

swjam wrote:
more than one device can be associated to an IOCP

True (more than one handle - not necessarily device).

swjam wrote:
each device would have its own thread pool

False. The number of threads in the pool is determined by how many threads
are waiting on the completion port with GetQueuedCompletionStatus().

swjam wrote:
each thread pool is associated to a particular function. which is why ANY of the threads (although usually the last in) in the pool can be awakened each time there is a new entry in the completion queue.

False.

swjam wrote:
somehow IOCP knows which thread in a pool to wake up depending on which IOCP-associated device has a completed IO request.

False. You can make no assumptions on which thread waiting in GetQueuedCompletionStatus()
will "wake up", unless you only have one thread in the pool.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: iocompletionport (IOCP) and threads

led mike7-Oct-08 4:17

led mike

7-Oct-08 4:17

Wow. Early for you, what up? Smile | :)

led mike

Re: iocompletionport (IOCP) and threads

Mark Salsbery7-Oct-08 4:23

Mark Salsbery

7-Oct-08 4:23

LMAO!

Since you asked, I had mexican food last night that's just not digesting...
I couldn't sleep any longer!

Hmm usually I'm turning my computer on about now...

It's good to work at home Smile | :)

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: iocompletionport (IOCP) and threads

swjam7-Oct-08 4:37

swjam

7-Oct-08 4:37

Mark Salsbery wrote:
False. The number of threads in the pool is determined by how many threads
are waiting on the completion port with GetQueuedCompletionStatus().

i'm still tad confused

say multiple devices are associated to a completion port. surely each function will be different for each thread associated with a device? how then does the system know which one to wake up when an entry appears in the competion queue?

----------------------------------------------------------
"unzip; strip; touch; finger; mount; fsck; more; yes; unmount; sleep" - my daily unix command list

Re: iocompletionport (IOCP) and threads

Mark Salsbery7-Oct-08 4:53

Mark Salsbery

7-Oct-08 4:53

IOCPs are a bit confusing at first Smile | :)

swjam wrote:
surely each function will be different for each thread associated with a device?

Not so. There's no parameter passed to GetQueuedCompletionStatus() that associates
the thread with a certain device. You'll need to provide any association yourself
in your overlapped structures.

swjam wrote:
how then does the system know which one to wake up when an entry appears in the competion queue?

It's undocumented, but it may just take the next thread waiting in
GetQueuedCompletionStatus(). There's no particular order or association with
a certain thread.

These articles helped me a lot when I first used an IOCP.
They are socket-related but the same principles apply to any
overlapped IO device...

Writing Windows NT Server Applications in MFC Using I/O Completion Ports[^]
Write Scalable Winsock Apps Using Completion Ports[^]
INFO: Design Issues When Using IOCP in a Winsock Server[^]

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

WinObj Question/Documentation ???

ForNow7-Oct-08 2:12

ForNow

7-Oct-08 2:12

Hi,

I just downloaded WinObj doesn't seem like there is much documentation

Anyway here is my Question

If while stepping thru my Code (Debugging) after I execute CreateEvent (with name) I get a Handle Back

If I then Bring up WinObj Shouldn't I see that Event if I open up the Kernel Object folder

Convert Integer to CString

phanindra varma7-Oct-08 1:06

phanindra varma

7-Oct-08 1:06

hello,

i have one integer array....{1,12,3,64,555}
i need to convert each integer as "CString"

i try to use Format() like
ex:

CString str;
int i=0;
str.Format("%d",i);

It wasa giving an Error.

Can any one help me in this regard.

Thanks in advance....!!!!! Rose | [Rose]

Re: Convert Integer to CString

Michael Schubert7-Oct-08 1:08

Michael Schubert

7-Oct-08 1:08

I can't see anything wrong with this code. What error are you getting?

Re: Convert Integer to CString

Rajesh R Subramanian7-Oct-08 1:36

Rajesh R Subramanian

7-Oct-08 1:36

phanindra varma wrote:
str.Format("%d",i);

Are you doing a fully Unicode build? Are you missing the _T macro? Have you tried: str.Format(_T("%d"),i); instead?

Many are stubborn in pursuit of the path they have chosen, few in pursuit of the goal - Friedrich Nietzsche

.·´¯`·->Rajesh<-·´¯`·.
[Microsoft MVP - Visual C++]

Re: Convert Integer to CString

Michael Schubert7-Oct-08 1:39

Michael Schubert

7-Oct-08 1:39

That's pretty much the only explanation for this code to fail...

Re: Convert Integer to CString

phanindra varma7-Oct-08 4:18

phanindra varma

7-Oct-08 4:18

Thanks.....

I forget _T();

Thanks again.. because Even for this silly question also u r guided me in a rigtt way....

Bye....

Re: Convert Integer to CString

Rajesh R Subramanian7-Oct-08 5:55

Rajesh R Subramanian

7-Oct-08 5:55

That's fine, but please make sure that you provide all the necessary information with your query, so that it would be easier for others to help you.

You said there was an error, but did not say what it was. Take care of these things in the future.

Many are stubborn in pursuit of the path they have chosen, few in pursuit of the goal - Friedrich Nietzsche

.·´¯`·->Rajesh<-·´¯`·.
[Microsoft MVP - Visual C++]

Re: Convert Integer to CString

phanindra varma18-Oct-08 4:04

phanindra varma

18-Oct-08 4:04

O.k Thanks for the Suggestion !!!!!

Re: Convert Integer to CString

vijay_aroli7-Oct-08 6:26

vijay_aroli

7-Oct-08 6:26

In addition to what Rajesh said, I would also advice you not to use SMS text while posting messages here. Smile | :)

Regards,
Vijay.

Re: Convert Integer to CString

David Crow7-Oct-08 3:36

David Crow

7-Oct-08 3:36

phanindra varma wrote:
It wasa giving an Error.

Turn your monitor around so we can see it. Roll eyes | :rolleyes:

"Love people and use things, not love things and use people." - Unknown

"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch

Re: Convert Integer to CString

Michael Schubert7-Oct-08 3:49

Michael Schubert

7-Oct-08 3:49

Re: Convert Integer to CString

Rajesh R Subramanian7-Oct-08 5:10

Rajesh R Subramanian

7-Oct-08 5:10

How much I love your comments.

Many are stubborn in pursuit of the path they have chosen, few in pursuit of the goal - Friedrich Nietzsche

.·´¯`·->Rajesh<-·´¯`·.
[Microsoft MVP - Visual C++]

Re: Convert Integer to CString

ThatsAlok7-Oct-08 19:27

ThatsAlok

7-Oct-08 19:27

Rajesh R Subramanian wrote:
How much I love your comments.

"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/xml>

Re: Convert Integer to CString

Hamid_RT7-Oct-08 5:13

Hamid_RT

7-Oct-08 5:13

You have powrful eyes. Big Grin | :-D

Timer Problem

MsmVc7-Oct-08 0:11

MsmVc

7-Oct-08 0:11

Hi All

I am useing timer.And that timer i am calling function FolderCopy().Which is working but after 2min code is hange.I havn't figure out what's a exactaly problem.Code is here.OnStartTimer i am calling in

OnInitDialog()

void CAbc::OnStartTimer() 
{

    SetTimer(1,10000, 0);
	
	
}

void CAbc::OnTimer(UINT_PTR nIDEvent)
{	
	FolderCopy();
	
	CDialog::OnTimer(nIDEvent);
}

void CAbc::FolderCopy()
{ 
CString finalString;
		 
		for(int aq=0;aq<20;aq++)
		{
		
	
		finalString=a1[aq];
				
		char * szMyString = (char *)(LPCTSTR)finalString;	
		
		PathRemoveFileSpec(szMyString);
		
		CString string = _T(szMyString);
				
		CString string1=string;
		string1 +='\0';
		int nLen = string1.GetLength();

		LPCSTR lpszBuf = string1.GetBuffer(nLen);

		string1.ReleaseBuffer();
	
		LPCSTR pF=lpszBuf;
		
		LPCSTR pT="c:\\Testing";
	
			
		SHFILEOPSTRUCT sf;
		memset(&sf,0,sizeof(sf));
		sf.hwnd = 0;
		sf.wFunc = FO_COPY;
		sf.pFrom = pF;
		sf.pTo = pT;
		sf.fFlags = FOF_NOCONFIRMATION | FOF_NOCONFIRMMKDIR | FOF_NOERRORUI;
 
		 int n = SHFileOperation(&sf);
		if( n == 0)
		{
			  AfxMessageBox("Success\n");
		 }
		else
		 {
			AfxMessageBox("Failed\n");
		 }

		}
		
		
}

Plz help me Rose | [Rose]

Re: Timer Problem

Cedric Moonen7-Oct-08 0:15

Cedric Moonen

7-Oct-08 0:15

The Ontimer function will still be called in the same thread, if the FolderCopy function is a lenghty operation, your GUI will freeze because it is not able to process messages anymore. You should use a worker thread for that task. Take a look at this great article[^].

Cédric Moonen
Software developer

Charting control [v1.5]
OpenGL game tutorial in C++

Re: Timer Problem

MsmVc7-Oct-08 0:40

MsmVc

7-Oct-08 0:40

Thank for reply.it's a good artical.Can you give me tips,hoe i use thread for do that task.

Thanks in advance.. Rose | [Rose]

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