C / C++ / MFC Discussion Boards

Re: different post message and send message in vc++

David Crow22-Jan-10 4:15

David Crow

22-Jan-10 4:15

mathy wrote:
In Mfc what is the differents between post message and send message....

While SendMessage() and PostMessage() can be used within MFC code, they are not related. They are from the Windows SDK.

"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

Re: different post message and send message in vc++

loyal ginger22-Jan-10 4:47

loyal ginger

22-Jan-10 4:47

Another interview question? Don't accept an offer from that place!

COM Query

pandit8421-Jan-10 22:27

pandit84

21-Jan-10 22:27

How COM Object gets removed from the memory?
Suppose there are 4 clients using our COM Component, One by One they goes out of scope ..At which point the component knows that it has to unload from memory.? Once the COM Object's reference count reached to zero then at this point which mechanism works to remove it from the memory.

Thanks

Re: COM Query

Adam Roderick J21-Jan-10 22:54

Adam Roderick J

21-Jan-10 22:54

Do u mean the interface count?
if so then [^]

Величие не Бога может быть недооценена.

Re: COM Query

Stuart Dootson21-Jan-10 23:02

Stuart Dootson

21-Jan-10 23:02

The COM object's 'Release' method would call delete this; when the reference count is zero to delete itself.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

CodeProject MVP for 2010 - who'd'a thunk it!

Re: COM Query

CPallini21-Jan-10 23:39

CPallini

21-Jan-10 23:39

pandit84 wrote:
Once the COM Object's reference count reached to zero then at this point which mechanism works to remove it from the memory.

It is a responsibility of the COM object developer. When the reference count goes to zero then there are no references pending on the object (probably there aren't...: the reference count is shared mechanism of both the COM server and the client) and the object may choose to free its COM resources (as it usually do).
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: COM Query

pandit8422-Jan-10 0:53

pandit84

22-Jan-10 0:53

Thanks a lot for your great reply

Re: COM Query

CPallini23-Jan-10 2:41

CPallini

23-Jan-10 2:41

You are welcome.
Smile | :)

A problem about the rubbish on win7

nenfa21-Jan-10 21:11

nenfa

21-Jan-10 21:11

now, i simulate one desktop.
After i clean the full rubbish, which message is sent to the desktop for notifying you to change the icon of rubbish.
thank you very much.

Re: A problem about the rubbish on win7

«_Superman_»22-Jan-10 16:55

«_Superman_»

22-Jan-10 16:55

It has always been called as recycle bin.
People may not understand you if you call it by other names.

Anyway, try doing an invalidate on the desktop.

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

Microsoft MVP (Visual C++)

Replacing some bytes in a file in binary mode

sunny_vc21-Jan-10 20:55

sunny_vc

21-Jan-10 20:55

Hi,
I have a file which is in binary mode.(I am using stdio functions fwrie,fread,fseek)
I have to read this file in binary mode and needs to replace some of the bytes in this file.
It contains around 1000 entries with 2 bytes each.
I know the location of bytes which is to be changed, like 100th entry.
Is there anyway to change that specific bytes, without copying in to other file.
As I have small memory I can not copy into other file and recopy with changed bytes.
So on the fly i want to change specific bytes.

please tell me if any method is there to do this.?

Regards,
Sunil Kumar

Re: Replacing some bytes in a file in binary mode

CPallini21-Jan-10 21:24

CPallini

21-Jan-10 21:24

You may open the file for read/write (i.e. "r+") go to intended position with fseek and change the byte content with fwrite.
Smile | :)

Re: Replacing some bytes in a file in binary mode

sunny_vc21-Jan-10 21:34

sunny_vc

21-Jan-10 21:34

yeah.i've used the same thing.But that is not working.

Regards,
Sunil Kumar

Re: Replacing some bytes in a file in binary mode - fixed, thanks to superman

CPallini21-Jan-10 21:44

CPallini

21-Jan-10 21:44

My code (beware: error checking omitted for concision)

FILE * fp = fopen("foo.bin", "rb+");
fseek(fp, 10, SEEK_SET);
fwrite("#", 1, 1, fp);
fclose(fp);

is working fine.
Smile | :)

modified on Friday, January 22, 2010 6:43 AM

Re: Replacing some bytes in a file in binary mode

«_Superman_»21-Jan-10 22:35

«_Superman_»

21-Jan-10 22:35

Except that for binary you could do a "rb+".

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

Microsoft MVP (Visual C++)

Re: Replacing some bytes in a file in binary mode

CPallini22-Jan-10 0:43

CPallini

22-Jan-10 0:43

Oh, thanks...
Smile | :)

Re: Replacing some bytes in a file in binary mode

iceman861621-Jan-10 21:48

iceman8616

21-Jan-10 21:48

did you remember fflush() the buffers?

Re: Replacing some bytes in a file in binary mode

Stuart Dootson21-Jan-10 23:05

Stuart Dootson

21-Jan-10 23:05

As superman's said elsewhere in this thread, use binary mode when you open the file, using

FILE * fp = fopen("foo.txt", "rb+");

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

CodeProject MVP for 2010 - who'd'a thunk it!

File Manipulation

Chandrasekharan P21-Jan-10 20:03

Chandrasekharan P

21-Jan-10 20:03

I am doing an application where i am writing something to an excel sheet. Initially i am writing into 2 rows and coloums. i have the heading and then the values and then closing the file. Now at a later point of time i need to open the same file and append. starting writing from the third row. How can i do that?

Re: File Manipulation

Rajesh R Subramanian21-Jan-10 20:16

Rajesh R Subramanian

21-Jan-10 20:16

Use excel automation. Refer to one of those numerous samples provided in MSDN.

Or you could use something like BasicExcel - A Class to Read and Write to Microsoft Excel[^].

“Follow your bliss.” – Joseph Campbell

Re: File Manipulation

Cedric Moonen21-Jan-10 20:27

Cedric Moonen

21-Jan-10 20:27

What is the format of your file ? A CSV file or really an excell spreadsheet ? Are you using excell automation ?

Cédric Moonen
Software developer

Charting control [v3.0]
OpenGL game tutorial in C++

Re: File Manipulation

David Crow22-Jan-10 4:17

David Crow

22-Jan-10 4:17

Chandru080 wrote:
Now at a later point of time i need to open the same file and append. starting writing from the third row. How can i do that?

How did you write to the second row?

Handle to a video played in a video player

lazy_panther21-Jan-10 19:42

lazy_panther

21-Jan-10 19:42

Hi,

I have a video playing in a video player. Irrespective of video player, I need the handle to the video being played. I have user-specified screen co-ordinates, now I need to convert the screen co-ordinates into frame co-ordinates of the video. To convert screen co-ordinates to video-frame co-ordinates and to further process video frames, I need handle to the video.

I am using Visual Studio and C++ for Win32 programming.

Any pointer?

Thanks

Create function error in CView Class

diarabit21-Jan-10 19:16

diarabit

21-Jan-10 19:16

I found a technical document for adding multiple view to a single document project.
http://msdn.microsoft.com/en-us/library/s199bks0%28VS.80%29.aspx[^]

I made a form view and tried to create it in my project.

When I tried it first, it was succeeded. But when I made it again I got an error message.

It is my code copy from MSDN document.

CView*	pActiveView = ((CFrameWnd*)m_pMainWnd)->GetActiveView();
	m_pOldView = pActiveView;
	m_pSearchView = (CView*)new CSearchMember;
	
	CDocument*	pCurrentDoc = ((CFrameWnd*)m_pMainWnd)->GetActiveDocument();

	CCreateContext newContext;
	newContext.m_pNewViewClass = NULL;
	newContext.m_pNewDocTemplate = NULL;
	newContext.m_pLastView = NULL;
	newContext.m_pCurrentFrame = NULL;
	newContext.m_pCurrentDoc = pCurrentDoc;

	UINT viewID = AFX_IDW_PANE_FIRST+1;
	CRect rect(0,0,0,0);

	m_pSearchView->Create(NULL, NULL, WS_CHILD, rect, m_pMainWnd, viewID, &newContext);
	m_pSearchView->SendMessage(WM_INITIALUPDATE, 0, 0);

In debugging mode, I could find a place occurred error.

BOOL CFormView::Create(LPCTSTR /*lpszClassName*/, LPCTSTR /*lpszWindowName*/,
	DWORD dwRequestedStyle, const RECT& rect, CWnd* pParentWnd, UINT nID,
	CCreateContext* pContext)
{
	ASSERT(pParentWnd != NULL);
	ASSERT(m_lpszTemplateName != NULL);

	m_pCreateContext = pContext;    // save state for later OnCreate

#ifdef _DEBUG
	// dialog template must exist and be invisible with WS_CHILD set
	if (!_AfxCheckDialogTemplate(m_lpszTemplateName, TRUE))
	{
		ASSERT(FALSE);          // invalid dialog template name
		PostNcDestroy();        // cleanup if Create fails too soon
		return FALSE;
	}

Because of m_plszTemplateName, this error is occurred.
But I don't know how do I solve.

Please advise for me.

Re: Create function error in CView Class [modified]

Nelek21-Jan-10 22:28

Nelek

21-Jan-10 22:28

Are you wanting to create the additional views on the fly? or creating them in edition time (for instance a CFormView in Resource.h) and attaching / opening them in run-time? With or Without MFC?

If the second there is another approach to get it, I used it in VC6 with MFC. But it is quite long to explain, if it is not what you want / need.

Regards.
--------
M.D.V. Wink | ;)

If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
Rating helpfull answers is nice, but saying thanks can be even nicer.

modified on Friday, January 22, 2010 4:52 AM

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.