C / C++ / MFC Discussion Boards

baerten18-Sep-07 0:10

18-Sep-07 0:10

I never made an application like this, but do you think it's necessairy to create
for each ball a thread?

If i should make it, i create a class Ball and instanciate for each ball a new object.
Because the drawing is made (in every case) at the main thread (The GUI-Thread)

Normally the balls are flying with the same speed, so with a timer you redraw each time
the new position of the balls. The new position of the ball is calculated into the object.

I hope i don't say bullshit Smile | :)

Re: An Multi Thread SDI application

Marimuthu.r18-Sep-07 1:19

Marimuthu.r

18-Sep-07 1:19

baerten wrote:
I never made an application like this, but do you think it's necessairy to create
for each ball a thread?

What I had in mind was for each thread, within that thread, I Create a ball object and in a while loop, get the necessary paramerers (trajectory) of the ball by making call functions. Periodically I keep updating the UI with the info.

Re: An Multi Thread SDI application

Waldermort18-Sep-07 2:34

Waldermort

18-Sep-07 2:34

You really don't need to be using a thread for each ball. As another poster said, create an instance of a class for each and update the class on each loop of your code.

You also might want to do some searching for an algorithm called "collision detection" which is almost exactly what you are trying to accomplish.

Waldermort

Re: An Multi Thread SDI application

Russell^'18-Sep-07 0:10

Russell^'

18-Sep-07 0:10

Marimuthu.pesit wrote:
how do i start of with this application?

this[^] is a good article to start.
Rose | [Rose]

Russell

Re: An Multi Thread SDI application

Cliff Hatch18-Sep-07 9:04

Cliff Hatch

18-Sep-07 9:04

Your application sounds very similar to the sample program MTGDI in the MSDN Library. It might help you get started.

MTGDI[^]

Best Regards

Cliff

ON_COMMAND_EX

Rockone17-Sep-07 22:25

Rockone

17-Sep-07 22:25

it seems that ON_COMMAND_EX just works in doc/view architecture. Can anyone give me some tips about it?
thank you.

Re: ON_COMMAND_EX

ashukasama17-Sep-07 22:57

ashukasama

17-Sep-07 22:57

have a look

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=514836&SiteID=1

http://www.codeguru.com/forum/showthread.php?t=61254

http://www.codeguru.com/forum/showthread.php?t=216400

Smile | :)

Re: ON_COMMAND_EX

Rockone17-Sep-07 23:20

Rockone

17-Sep-07 23:20

Thank you for your reply.
I already google it and search it on codeproject and codeguru before posting this message.

Yes, it works well for Doc & View architecture.

my architecture is CMainFrame and CMyView (derived form CWnd, not CView) and without Doc.
And it has a custom tool bar and a custom status bar.

Re: ON_COMMAND_EX

David Crow18-Sep-07 3:09

David Crow

18-Sep-07 3:09

Do you need ON_COMMAND_EX() instead of ON_COMMAND().

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: ON_COMMAND_EX

Rockone18-Sep-07 16:12

Rockone

18-Sep-07 16:12

I need process the message in the child window and parent window.
child window uses ON_COMMAND_EX and parent window uses ON_COMMAND.

Re: ON_COMMAND_EX

David Crow19-Sep-07 2:40

David Crow

19-Sep-07 2:40

Rockone wrote:
I need process the message in the child window and parent window.

Why would you need to do this?

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: ON_COMMAND_EX

Rockone19-Sep-07 23:45

Rockone

19-Sep-07 23:45

just add

<br />
if ( m_wndToolBar.OnCmdMsg(...) )<br />
{<br />
   return TRUE;<br />
}<br />

in function

<br />
CMainFrame::OnCmdMsg(...)<br />

before return default process.

Re: ON_COMMAND_EX

Mark Salsbery18-Sep-07 6:14

Mark Salsbery

18-Sep-07 6:14

I'm not sure why you think it ONLY works in doc/view. Smile | :)

Mark

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

Re: ON_COMMAND_EX

Rockone18-Sep-07 16:42

Rockone

18-Sep-07 16:42

I already try some cases, it works well in doc/view case.

I get some source codes from sourceforge.net, it uses ON_COMMAND_EX and is not doc/view case.
it just has CMainFrame and a view derived from CWnd, without doc.

basic issue Mode no value

monsieur_jj17-Sep-07 22:13

monsieur_jj

17-Sep-07 22:13

this snippet below:

// find the property
	redmap::mapi::FoundProperty prop 
		= m_Message->FindProperty(PropertyID);

-----
will call this snippet:

class Message
	{
		enum Mode { CLOSED, OPEN };
		IMessagePtr m_Message;
		AutoMapiPtr<SPropValue> m_PropertyCache;
		PropertyMap m_MessageProps;
		SRowSet* m_AttachCache;
		unsigned long m_AttachCount;
		boost::scoped_array<PropertyMap> m_AttachProps;
		Mode m_Mode;

	public:
.
.
.
.
.
FoundProperty FindProperty(unsigned long PropertyTag)
		{
			assert(m_Mode == OPEN);
			return m_MessageProps.find(PropertyTag);
		}

now I am wondering as why m_Mode in the second snippet has no value at all.

Please enlighten me

If any of you requires additional code to expand this just say so.

Thank you,
Jj

-- modified at 4:12 Tuesday 18th September, 2007

Re: basic issue Mode no value

Iain Clarke, Warrior Programmer17-Sep-07 22:38

Iain Clarke, Warrior Programmer

17-Sep-07 22:38

As I read it, the programmer (I'm guessing it's not you) has just put an assert in there. (s)he could just be checking that things he expects to be true are actually true. Maybe unless m_Mode is OPEN, then m_MessageProps would be empty, and he wants to catch the reasons why the find routine would fail.

It's always possible this is a line of fossil code, and m_Mode is no longer necessary. But unless you understand the code, I'd leave it in also.

Iain.

Issue with pointer initialization in a simple thread

__yash__17-Sep-07 21:56

__yash__

17-Sep-07 21:56

hi,
I want to send a message on WinSock by calling socket.Send() in a thread.

UINT WorkerThreadForDelay1(LPVOID Param)<br />
{<br />
.<br />
.<br />
CMyView* ptr;<br />
iSent = ptr->m_sConnectSocket1.Send(LPCTSTR(m_strMessage), iLen);<br />
.<br />
.<br />
}

Note that:
1. CMyView is derived from CRecordView.
2. m_sConnectSocket1 is an object of a CAsyncSocket-derived class, declared in CMyView.

How do i initialize ptr here???

Re: Issue with pointer initialization in a simple thread

Cedric Moonen17-Sep-07 22:18

Cedric Moonen

17-Sep-07 22:18

You could pass it as your thread argument. If you look at the documentation of the create thread function that you use, you'll see that it can accept an argument, that will be passed to your thread function through the LPVOID Param.

So, you can simply do that in your thread function:

UINT WorkerThreadForDelay1(LPVOID Param)<br />
{<br />
.<br />
.<br />
CMyView* ptr = (CMyView*)Param;<br />

But be carefull not to use the GUI object directly in your thread.

Cédric Moonen
Software developer

Charting control [v1.2]

Re: Issue with pointer initialization in a simple thread

__yash__17-Sep-07 23:09

__yash__

17-Sep-07 23:09

hey Cedric,
Thanks man....i tried this out and it works....thanks Smile | :)

I was calling the thread as follows:

.<br />
AfxBeginThread(WorkerThreadForDelay1,NULL,THREAD_PRIORITY_LOWEST,0,0,NULL);<br />
.

Now i changed it to:

CMyView* me;<br />
me=this;<br />
AfxBeginThread(WorkerThreadForDelay1,me,THREAD_PRIORITY_LOWEST,0,0,NULL);

and then ofcourse wat you wrote:

UINT WorkerThreadForDelay1(LPVOID Param)<br />
{<br />
.<br />
CMyView* ptr = (CMyView*)Param;<br />
iSent=ptr->m_sConnectSocket1.Send(.....);<br />
}

Re: Issue with pointer initialization in a simple thread

Iain Clarke, Warrior Programmer17-Sep-07 22:45

Iain Clarke, Warrior Programmer

17-Sep-07 22:45

What you can do is to use the LPVOID parameter to hold a pointer to some class.

eg.

HANDLE CMyClass::CreateTheThread ()
{
    m_hThread = CreateThread (MyThreadRoutine, ...., this, ...);
    return m_hThread;
}

DWORD MyThreadRoutine (LPVOID pParam)
{
    CMyClass *pThis = (CMyClass *)pParam;
    ....
    return 0;
}

There are things to be careful of though. You have to ensure that the CMyClass object will last longer than the thread routine. Or at least longer than the thread routine will use it.

And in your routine, you are using CASyncSocket. This class uses asynchronous socket behaviour, and responds to messages from winsock, rather than blocking on them. It does *not* mean that it is thread safe. It *might* be if you only send from one thread, and read on another, but don't assume that. This is why I use pretty raw win32 code in my threads, as MFC is explicitly not thread friendly. I'll use CWnd derived classes for it, but only to get access to the m_hWnd member to post messages back to them.

Iain.

Re: Issue with pointer initialization in a simple thread

__yash__17-Sep-07 23:22

__yash__

17-Sep-07 23:22

hey Iain,
Thanks for your support.
I m new to the concept of threads- in fact just 1 day old with threads :p
I found a very simple example yesterday on the net for using threads and used it:

AfxBeginThread(...);<br />
<br />
UINT Thread_name(LPVOID Param)<br />
{}

Now as to why i wanted to use threads is because i was losing quite a number of data strings(Machine->Software) as i wanted to provide a fixed-delay between two data transfer(Software->Machine). So i m using a thread to achieve this delay.

So now for the problem i posted i m now using LPVOID pointer to hold a pointer to my View class.

Thanks and Regards,
yash

P.S:
You would also like to see my reply to Cedric in this same thread

"@err,hr" equivalent in VC 2005

Mohammed Asif Palimar17-Sep-07 21:45

Mohammed Asif Palimar

17-Sep-07 21:45

Hi,
I used VC6 earlier.In which i was able to see the Last error by placing "@err,hr" on the watch window.i.e the value returned by GetLastError() function.

But now im using VC2005, the statement will not evaluate in VC2005 at all..
Is there any methods to get the Last error in watch window of VC2005?
Regards,
Mohammed Asif

Re: "@err,hr" equivalent in VC 2005

prasad_som18-Sep-07 2:10

prasad_som

18-Sep-07 2:10

It is still there. You must be missing something very obvious.

Prasad
MS MVP - VC++

Re: "@err,hr" equivalent in VC 2005

Mohammed Asif Palimar20-Sep-07 17:58

Mohammed Asif Palimar

20-Sep-07 17:58

Hi Prasad,
Well i couldn figure it out what im missing to get the value evaluated in VC2005.VC2005 is freshly installled in my system.Is any settings to be done to get the same?

Regards,
Mohammed Asif

Re: "@err,hr" equivalent in VC 2005

prasad_som20-Sep-07 18:09

prasad_som

20-Sep-07 18:09

No, setting needs to be done. I hope, you are puting @err,hr in quotes("@err,hr".

Prasad
MS MVP - VC++

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