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bolleperdu wrote: Whereever I look for help, it appears to be too complicated for a beginner like me. I just want my programm to have 2 threads: 1 for the serial communication and 1 for the GUI.
http://www.flounder.com/workerthreads.htm[^]
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
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Thanks for the response! The problem is that I want to show how much of the serial data is allready transmitted.
My programming skills are extremely basic: I create my forms using the windows form designer , I don't create them from my own code.
Would using the class "using namespace System::Threading;" for my threading be the easiest way?
<br />
try<br />
{<br />
StreamReader^ sr = gcnew StreamReader(teversturen);
{<br />
String^ line;<br />
int lengte = (unsigned int)sr->BaseStream->Length; <br />
int percent; <br />
while (!(sr->EndOfStream::get()))<br />
{<br />
percent = (((unsigned int)sr->BaseStream->Position / lengte) * 100);
toolPCT->Text = percent.ToString() + "%";
<br />
line = sr->ReadLine();
sp->WriteLine(line);
Form1::Update();
}<br />
}<br />
sr->Close();<br />
<br />
}<br />
catch (Exception^ e)<br />
{<br />
richTextBox1->Text += "The file not be read:\n";<br />
richTextBox1->Text += e->Message + "\n";<br />
sp->Close();<br />
}
Above you can find my code. I would like the percentage to be shown at least with an accuracy of 10 pct, or an update every 2 - 5 seconds. If this could be achieved without multithreading, that would please me even more:p The serial communication takes lots of time and the users would like to be able to cancel, see the status, ...
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Hi, All.
I have problem in my app. In my app, i have aciton [COPY File/Folder], switch Window Explore. When you right click > Paste, i want to active my app to run some function. after that, Do Paste.
Now, i will use hook to do that but i don't know, when window explorer paste, it call what API function.
Please, help me to to solve this problem.
Thanks.
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Normaly pasting is accomplished through the clipboard; that is you query the clipboard for the current items available for pasting. You can search for pasting in the MSDN, but you might have more success looking at OLE information on things like "drag and drop". Unless you need to know specificaly that the item being pasted is coming from Windows Explorer, then you should not need a hook. Of course if the function doing the pasting is in a control that you are using in you application, then you would need to hook that control.
INTP
Every thing is relative...
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thank you very much. i try and will send you result.
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i use delayed rendering Clipboard
BeginWaitCursor();
OpenClipboard()
::EmptyClipboard();
::SetClipboardData (CF_HDROP, NULL);
::CloseClipboard();
EndWaitCursor();
and i process message
use with WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
switch(message)
{
case WM_RENDERFORMAT:
function1();
case WM_RENDERALLFORMATS:
function2();
case WM_DESTROYCLIPBOARD:
function3();
when use right click, my app immediately active and call function to function1->2->3. I think is not true for my problem.
probable, i don't understand your solution.
Can you help me again.
Best regards and many thanks.
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I did not really give a solution, I just suggested an area to search for the information. I beleive there are articles at CP (or CodeGuru) on the subject.
I thought you where pasting to your app from the clipboard. What you are showing me is a possible method for adding something to the clipboard. Also your swith() has no break statements in it, so if the case is WM_RENDERFORMAT, then all the functions will be called (function1(), function2(), and function3()).
Well it's 3:43 AM here, so I have to say good night.
INTP
Every thing is relative...
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I want to desgin a MDI application window which look and feel like Microsoft Visual Studio 2005 with the property box etc. The client area should be like MS Access Report Designer with header,footer,rulers sections. How can design such a window
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Hire a team of programmers to help you. Otherwise look at the frame works available, that may provide some of the features you are looking for. There may be anouther way, if the user of the software has MS Access Report Designer installed on the same system, but I do not know. You never know, somebody may have designed a drop in that looks like what you are looking for.
INTP
Every thing is relative...
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Hello
I am using CWinThread for threading in MFC. I want to terminate a thread from another function not in the thread function itself. Can i do that?
Thank You.
We Believe in Excellence
-- modified at 1:10 Friday 17th February, 2006
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Briefly: TerminateThread()
Details: Avoid using this function:
a) Proper application cleanup does not occur: C++ object destructors aren't called, data isn't flushed to disk, and so on.
b) If TerminateThread is used, the system does not destroy the thread's stack until the process that owned the thread terminates.
c) DLLs usually receive notifications when a thread is terminating. If a thread is forcibly killed with TerminateThread, however, the DLLs do not receive this notification, which can prevent proper cleanup.
If you link your application to the C++ standard library, consider using _beginthreadex(...) and _endthreadex(...).
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Aqueel wrote: I want to terminate a thread from another function
if the other function is the part of another thread you can terminate the first thread using a signaling mechanism.
"Every morning I go through Forbes list of 40 richest people in the world. If my name is not in there, I go to work..!!!"
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Your asking for trouble even thinking of calling TerminateThread. Here's an example program which shows the kind of thing that can go wrong:
------------------------------------------
#include <windows.h>
CRITICAL_SECTION g_cs;
void ShowMessageBox()
{
EnterCriticalSection(&g_cs);
MessageBox(NULL, "Hello", "ShowMessageBox", MB_OK);
LeaveCriticalSection(&g_cs);
}
DWORD WINAPI ThreadProc(LPVOID lpParameter)
{
ShowMessageBox();
return 0;
}
int main(int argc, char* argv[])
{
InitializeCriticalSection(&g_cs);
// Start thread.
DWORD ThreadID;
HANDLE hThread = CreateThread(NULL, 0, &ThreadProc, 0, 0, &ThreadID);
// Wait for one second then kill the thread.
// It still holds the CRITICAL_SECTION!!!
Sleep(1000);
TerminateThread(hThread, 0);
// We've killed the "ShowMessageBox" API, permanently, calling it now
// causes this thread to dead lock!
ShowMessageBox();
DeleteCriticalSection(&g_cs);
return 0;
}
------------------------------------------
In this program calling TerminateThread permanently breaks ShowMessageBox because we killed the thread when it still held a lock. This is the worst kind of bug as it's very hard to reproduce as it's sensitive to timing. If you're calling Win32 functions many of them will briefly hold locks, if you terminate a thread while it is holding one you're screwed.
Moral: Don't call TerminateThread. There are exceptions but very few.
The only real safe way to terminate a thread from another thread is to ask it nicely. This generally involves signaling an event and then waiting on the thread handle.
Steve
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Absolutely, there are plenty of trouble with this function that is why I suggested avoiding it. It seems to me though that Aqueel wanted something like this asking
[quote]to terminate a thread from another function not in the thread function itself[/quote].
So, he does not seem to want to terminate the thread from "inside" for whatever reason. 
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I understand that you suggested he avoid it. I just wanted to clarify the dangers as in general if you use TerminateThread then it is a case of the cure being worse then the disease.
Steve
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Can he want to use it for debug purposes? Say, when his other thread freezes, does not exit properly, stops processing messages, then it may be OK to use it to terminate the other thread and print a status info?
BTW, thanks for the code. For my notes I should keep your example as another reason to avoid it.
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There may be times when you have little choice, so I guess the answer is yes. That said if the thread froze while holding a lock you've got a problem - But if this is the case you've got a problem anyway as it's frozen so I guess you're not making anything any worse. In general once you've terminated a thread the state of the whole process is suspect.
Steve
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When using a CWinThread object it is simple to terminate a thread.
1. if you have pointer to the object you can use:
CMyWinThread* pThread;
pThread->PostThreadMessage(WM_QUIT, NULL, NULL) This will cause the thread, when idle to stop.
The thread will go to the ExitInstance function where the clean up can begin.
2. if you don't have a pointer to the object but you have the Thread Id, you can use:
DWORD dwThreadId;
::PostThreadMessage(dwThreadId, WM_QUIT, NULL, NULL); With the same results
3. if you have neigther you need to have a common object to signal the thread to stop. This object
must be protected by thread synchronisation objects (like CMutex, CCriticalSection) or you can use
the CEvent to signal the thread to stop. I prefer one of the first two solutions because you don't
need to have a polling mechanisme to check if you need to stop or not. The third solution is preffered when the thread needs to be stopped during a lengthy operetation.
codito ergo sum
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Hi, someone has PM'med me but I can't sent a reply, so i will answer here.
Barry wrote: I have a situation where I have a user interface thread that is opening a dialog with a progress dialog that is used to show progress on processing going on in the parent thread. The underlying dialog is wrapped in a thread-safe class so messages to the dialog are handled properly. When processing in the parent thread is complete the dialog is gracefully shut down. If the dialog is being moved around when the parent thread tries to shut the thread down by posting a WM_QUIT method to the thread, the ExitInstance method in the CWinThread-derived class used to handle the thread never gets invoked and the thread remains active. I also tried to add a user-defined message with a message handler but the message handler never got invoked when the parent thread sent the message to the thread. Any clues?
I have created a simular test version an can confirm the same error.
I have browsed to the MFC source and have found the problem I have found a solution probably on of the worst in oo design but what the heck if even MFC isn't working like it should 
First let me explain what happens.
I have a DLG(main) application wich creates a thread. This thread creates a Modless dlg and closes it on exiting the thread.
The main applaction sends a m_pCloseThread->PostThreadMessage(WM_QUIT,0,0);
To let the thread exit.
This works like intended as long as the dlg in the thread doesn't get moved.
The normal WM_QUIT is getting processed in CWinthread::Run function
...
if (!PumpMessage())
return ExitInstance();
..
But when you move over the window with you mouse the messages of your movement should be redirected to the Message loop of the dialog.
If you click and hold down the left mouse button (in order to drag, but not nessacary) the full message handling is done by the DLG message loop. The thread message loop never gets called any more until you leave the mousebutton. The posted WM_QUIT message isn't processed by the thread message loop (let me call this the parent loop) but by another loop, this loop (child) probably see that the message isn't for him and neglects it.
The parent loop doesn't know anything of that message. I believe it’s a design flaw in the MFC, but this is just my 2 cents :P
I hope that I explained it correctly.
But how do we solve this Design-flaw: Like I said before I have done it Quick and dirty.
1. I've added a Boolean member in the dialog to notify the thread that There was a WM_QUIT sent
2. In the dialog I need to capture a WM_QUIT message. This is done by overriding the WindowProc function (child loop)
LRESULT CClosingInfo::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{
if(message == WM_QUIT)
{
m_bOopsImDead = true;
}
return CDialog::WindowProc(message, wParam, lParam);
}
3. I also need to override the thread loop (parent) which is in the CWinthread::run function.
The code inside the function can be found in the thrdcore.cpp file of the MFC source codes
int CCloseTrhread::Run()
{
ASSERT_VALID(this);
_AFX_THREAD_STATE* pState = AfxGetThreadState();
BOOL bIdle = TRUE;
LONG lIdleCount = 0;
for (;; )
{
while (bIdle &&
!::PeekMessage(&(pState->m_msgCur), NULL, NULL, NULL, PM_NOREMOVE))
{
if (!OnIdle(lIdleCount++))
bIdle = FALSE;
}
do
{
if (!PumpMessage())
return ExitInstance();
if (IsIdleMessage(&(pState->m_msgCur)))
{
bIdle = TRUE;
lIdleCount = 0;
}
} while (::PeekMessage(&(pState->m_msgCur), NULL, NULL, NULL, PM_NOREMOVE));
if(m_pCloseWindow->m_bOopsImDead)
{
return ExitInstance();
}
}
}
4. Now instead of calling the thread to close, call the dlg
<code>m_pCloseThread->m_pCloseWindow->PostMessage(WM_QUIT, 0 ,0);
This works also when no one is dragging or holding the dialog.
Hope that this helps, or at least sets you on its way.
Let me know
Kurt Pattyn
codito ergo sum
-- modified at 18:52 Thursday 25th May, 2006
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Thank you friends!
Specially BadKarma! You solved my problem.
We Believe in Excellence
-- modified at 23:34 Friday 17th February, 2006
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Aqueel wrote: I am using CWinThread for threading in MFC. I want to terminate a thread from another function not in the thread function itself. Can i do that?
http://www.flounder.com/workerthreads.htm
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
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pDC->GetSafeHdc(); It will return a pointer to the existing memory or allocate the memory and then return the pointer to this allocated memory.
OR
how i can release this memory
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GetSafeHdc() does not return a pointer. It returns the handle of the device context - you don't need to "release" it.
Ryan "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"
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It returns a handle to an exiting HDC or NULL. If you single step through the code you will see that calling GetSafeHdc() is equivalent to return(hdc?hdc:NULL), which is kind of silly if you ask me. Because if the test codition faile "hdc?" then the hdc is already equivalent to NULL. The long and the short of it is that GetSafeHdc() does not allocate any memory, it just makes sure that the HDC returned is either valid or NULL.
INTP
Every thing is relative...
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anilksingh wrote: pDC->GetSafeHdc();
just return the reference to selected DC.. the CDC it self manage life cycle of the HDC object.. so you don't need to worry about it.
Secondly you can use DeleteDC api to delete DC
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
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