Non Ovelapped Serial I/O - C / C++ / MFC Discussion Boards

Re: UINT ThreadProc ( LPVOID param )

CPallini3-Aug-09 1:23

CPallini

3-Aug-09 1:23

I encourage you to read this [^].
Smile | :)

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]

Re: UINT ThreadProc ( LPVOID param )

susanne13-Aug-09 3:24

susanne1

3-Aug-09 3:24

okoay but i have an application crash hier:

#ifdef _DEBUG
void CTestView::AssertValid() const
{
CView::AssertValid(); // application crash
}

#ifndef _WIN32_WCE
void CTestView::Dump(CDumpContext& dc) const
{
CView::Dump(dc);
}
#endif
#endif

Re: UINT ThreadProc ( LPVOID param )

CPallini3-Aug-09 11:46

CPallini

3-Aug-09 11:46

You shouldn't use GUI stuff in worker threads.
Smile | :)

Re: UINT ThreadProc ( LPVOID param )

David Crow3-Aug-09 3:55

David Crow

3-Aug-09 3:55

Is there a question here that I'm failing to see? Confused | :confused:

"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown

"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

Re: UINT ThreadProc ( LPVOID param )

susanne13-Aug-09 5:23

susanne1

3-Aug-09 5:23

The question is when i pass (this) instead of (hwnd) to the ThreadProc function i get a crash. The question is above.

Re: UINT ThreadProc ( LPVOID param )

David Crow3-Aug-09 5:26

David Crow

3-Aug-09 5:26

How about formatting your code correctly AND using the <pre> tag?

Re: UINT ThreadProc ( LPVOID param )

Michael Dunn3-Aug-09 9:48

Michael Dunn

3-Aug-09 9:48

-> has higher precedence than a cast, you need parens around the cast so it's evaluated first:

((CTestView*) param)->SomeMethod();

--Mike--
Dunder-Mifflin, this is Pam.

Non Ovelapped Serial I/O

sunny_vc2-Aug-09 23:37

sunny_vc

2-Aug-09 23:37

HI all,
I am working on Non Overlapped serial I/O application.
I have only one thread to receive the data.For send i dont have any thread.
I just call Write file when i need to send .

My problem is, When I have my receive thread wait for an event using WaitCommEvent, it ties up the serial port. Then my sending function can't access the port with WriteFile. I knew waiting for a comm event would block the receiving thread but didn't expect that it would block use of the port.

Any suggestions on how to do non-overlapped communication, where the send fucntion can write while the receive thread waits for a comm event?

Regards,
Sunil Kumar

Re: Non Ovelapped Serial I/O

«_Superman_»2-Aug-09 23:54

«_Superman_»

2-Aug-09 23:54

Try to open the port twice using CreateFile.
Use one handle for writing and another for reading from the port.

«_Superman_»
I love work. It gives me something to do between weekends.

Re: Non Ovelapped Serial I/O

sunny_vc3-Aug-09 0:16

sunny_vc

3-Aug-09 0:16

I dont think I can use CreateFile twice.
It is unable to create the second time.The handle is getting some undefined value,
when it is opened the second time.

Regards,
Sunil Kumar

Re: Non Ovelapped Serial I/O

«_Superman_»3-Aug-09 0:21

«_Superman_»

3-Aug-09 0:21

You should be able to open more than once if you specify the FILE_SHARE_READ and FILE_SHARE_WRITE flags.

«_Superman_»
I love work. It gives me something to do between weekends.

Re: Non Ovelapped Serial I/O

CPallini3-Aug-09 0:46

CPallini

3-Aug-09 0:46

«_Superman_» wrote:
You should be able to open more than once if you specify the FILE_SHARE_READ and FILE_SHARE_WRITE flags.

You cannot do that with a communication resource (MSDN [^])

 The CreateFile function can create a handle to a communications resource, such as the serial port COM1. For communications resources, the dwCreationDisposition parameter must be OPEN_EXISTING, the dwShareMode parameter must be zero (exclusive access), and the hTemplateFile parameter must be NULL. Read, write, or read/write access can be specified, and the handle can be opened for overlapped I/O. 

Re: Non Ovelapped Serial I/O

sunny_vc3-Aug-09 0:59

sunny_vc

3-Aug-09 0:59

yeah, I am unable to open it twice even if I mention the shared attributes.
There is no other option for non overlapped I/O, if I have to WriteFile, when
my receive thread wait for an event using WaitCommEvent?

Regards,
Sunil Kumar

Re: Non Ovelapped Serial I/O

CPallini3-Aug-09 1:17

CPallini

3-Aug-09 1:17

As workaround, you may use the same thread for both I/O.
Smile | :)

Re: Non Ovelapped Serial I/O

sunny_vc3-Aug-09 2:05

sunny_vc

3-Aug-09 2:05

Even If I have to send data in the same receive thread,
I am unable to do as WaitCommEvent never returns.
My code block is:

 if (!SetCommMask( pc->hCommn, EV_RXCHAR))
 {
     //Error
 }
 for ( ; ; )
 {
 if (WaitCommEvent(pc->hCommn, &dwCommEvent, NULL))
 {

     do
     {
     if (ReadFile(pc->hCommn, &chRead, 1, &dwRead, NULL))
       {
          // A byte has been read; process it.
           pc->CopyRx(chRead);
       }
       else
       {
          // An error occurred in the ReadFile call.

          break;
       }
     }while(dwRead);
 }
else
   // Error in WaitCommEvent.
   break;
 }

Where can I call my send fucntion in this thread, if I have some data to send.
Please suggest.

Regards,
Sunil Kumar

Re: Non Ovelapped Serial I/O

«_Superman_»3-Aug-09 2:35

«_Superman_»

3-Aug-09 2:35

I was wondering if DuplicateHandle[^] will work.

«_Superman_»
I love work. It gives me something to do between weekends.

Re: Non Ovelapped Serial I/O

korvix3-Aug-09 15:42

korvix

3-Aug-09 15:42

You cannot do that with a communication resource (MSDN [^])

Re: Non Ovelapped Serial I/O

David Crow3-Aug-09 3:56

David Crow

3-Aug-09 3:56

Have you read this?

Re: Non Overlapped Serial I/O

sunny_vc3-Aug-09 4:53

sunny_vc

3-Aug-09 4:53

Hi,
I already read the article.But I am trying using Non overlapped I/O.
If it is impossible to do using Non overlapped, i will shift to overlapped.

Regards,
Sunil Kumar

Sobel - edge detection

adichavan2-Aug-09 22:22

adichavan

2-Aug-09 22:22

Hi all,

Anyone has the C source code for Sobel - edge detection filter for bitmap color image.

Pls support me the complete souce code.

Re: Sobel - edge detection

HimanshuJoshi2-Aug-09 22:47

HimanshuJoshi

2-Aug-09 22:47

Google[^] gave me This[^]. What did it gave to you?

Re: Sobel - edge detection

adichavan2-Aug-09 23:16

adichavan

2-Aug-09 23:16

thanx but i wana code in c not in cpp.

Re: Sobel - edge detection

Michael Schubert2-Aug-09 23:57

Michael Schubert

2-Aug-09 23:57

adichavan wrote:
i wana code

if youz wana code youz gonna have to writez it or search for itz...

Re: Sobel - edge detection

Chandrasekharan P3-Aug-09 0:05

Chandrasekharan P

3-Aug-09 0:05

adichavan wrote:
i wana code

Go Ahead!!!! who is stopping you..

Re: Sobel - edge detection

adichavan3-Aug-09 1:39

adichavan

3-Aug-09 1:39

i had write code in c i m new in image processing i stard studing it since last 1 month uptil now i read my image its header i displayed it & perform convlution with sobel operater the code is running but cant show the complit o/p if u dont want to help then live it OK i just want to compaire my code with other & dat cpp code i allready studied

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