Re: Alternative for TIMERs in MFC?? - C / C++ / MFC Discussion Boards

Re: Alternative for TIMERs in MFC??

Kiran Satish6-May-08 6:49

Kiran Satish

6-May-08 6:49

Yes... I know I haven't used threads in proper way in this particular application Poke tongue | ;-P

.
Well I used them in more sumple way, once the user clicks on 'Close Loop' button on one of the dialog boxes, I start a thread that does all the necessary work, but I remember it giving errors when I send/post messages to dialog boxes (but I am not sure) and the interface doesnt respnd anymore to user inputs.
Coming to TIMERs, here is how we are using currently-

<br />
//This is the code for the close loop user interface button<br />
void CAnalysisDlg::OnCloseloop() <br />
{<br />
 CButton *ClButton;<br />
 HICON icn;<br />
 ClButton = (CButton *)GetDlgItem(IDB_CLOSELOOP);<br />
 icn = ClButton->GetIcon();<br />
 if(icn == AfxGetApp()->LoadIcon(IDI_CLOSELOOP))<br />
 {<br />
  ClButton->SendMessage(BM_SETIMAGE,IMAGE_ICON,(LPARAM)AfxGetApp()->LoadIcon(IDI_LOOPCLOSED));<br />
  if(parent->closeLoop() == FALSE)<br />
  {<br />
   ClButton->SendMessage(BM_SETIMAGE,IMAGE_ICON,(LPARAM)AfxGetApp()->LoadIcon(IDI_CLOSELOOP));<br />
  }<br />
 }<br />
 else<br />
 {<br />
  KillTimer(1);<br />
  parent->Uncheck_Closeloop();<br />
 }<br />
}<br />
//This code goes into parent(main) dialog box<br />
BOOL CMainDlg::closeLoop()<br />
{<br />
//do some intializations and calculations here<br />
 if(OnAutoMeasure()==FALSE)<br />
  return FALSE;<br />
}<br />
<br />
BOOL CMainDlg::OnAutoMeasure()<br />
{<br />
//calculate the frequency of closed loop<br />
//do closed loop functions and update other dialog boxes as necessary<br />
//if there is nay error it returns false<br />
 SetTimer(1,1,NULL);<br />
 return TRUE;<br />
}<br />
<br />
void CMainDlg::OnTimer(UINT nIDEvent) <br />
{<br />
 CButton *ClButton;<br />
 HICON icn;<br />
 KillTimer(1);<br />
 ClButton = (CButton *)tbdisp->GetDlgItem(IDB_CLOSELOOP);<br />
 icn = ClButton->GetIcon();<br />
 if(icn == AfxGetApp()->LoadIcon(IDI_LOOPCLOSED))<br />
 {<br />
  if(closeloopsafety <= NUM_FALSE_RETURN_AUTOMEASURE)<br />
  {<br />
   if(OnAutoMeasure()==FALSE)<br />
    Uncheck_Closeloop();<br />
  }<br />
  else<br />
   Uncheck_Closeloop();<br />
 }<br />
 CDialog::OnTimer(nIDEvent);<br />
}<br />

I hope the code wont be too much of confusion Smile | :)

. But that how its basically works now.

PKNT

Re: Alternative for TIMERs in MFC??

toxcct6-May-08 6:25

toxcct

6-May-08 6:25

this is NOT because of the MFC's Timer (which is in fact a wrapper to Win32), but because Windows is NOT a Real Time OS...
so you cannot expect much efficiency from there.

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Re: Alternative for TIMERs in MFC??

Kiran Satish6-May-08 6:52

Kiran Satish

6-May-08 6:52

Yes.. its true. But I never had much of problems using threads in MFC, they used to work better. But well you can't compare it with other real-time OSes like Linux and other packages that you can get that makes Windows as real-time OS though Smile | :)

PKNT

Re: Alternative for TIMERs in MFC??

toxcct6-May-08 6:54

toxcct

6-May-08 6:54

but maybe your processor is overloaded in kernel mode...

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Re: Alternative for TIMERs in MFC??

Kiran Satish6-May-08 6:59

Kiran Satish

6-May-08 6:59

Good point, but I have 8 cores and I barely use one core at full clock (while running all our applications at the same time) and to say windows is not bad in scheduling processes on multi core systems and distributes evenly if not overloading OMG | :OMG:

PKNT

Re: Alternative for TIMERs in MFC??

JudyL_MD7-May-08 3:07

JudyL_MD

7-May-08 3:07

Kiran Satish wrote:
other real-time OSes like Linux

FYI, Linux is not a RTOS

Re: Alternative for TIMERs in MFC??

Kiran Satish7-May-08 4:59

Kiran Satish

7-May-08 4:59

Yes... I agree, but I am not saying about those commercial Linux Distros (like Fedora, Mandrake etc), there are many RTOSes based on Linux, I meant it in the same way I said about Windows RTOS version packages.

PKNT

Re: Alternative for TIMERs in MFC??

Jeremy Thornton6-May-08 15:15

Jeremy Thornton

6-May-08 15:15

from MSDN article: How To Use QueryPerformanceCounter to Time Code

Function Units Resolution
---------------------------------------------------------------------------
Now, Time, Timer seconds 1 second
GetTickCount milliseconds approx. 10 ms
TimeGetTime milliseconds approx. 10 ms
QueryPerformanceCounter QueryPerformanceFrequency same

not so much in MFC but Win32 perhaps? your best resolution is probably 10ms

NB multicore breaks simple RDTSC approaches you may read about

my old article on timing: http://www.codeproject.com/KB/cpp/precision_timer.aspx[^]

Determining if an drang'n'drop event is active

tibiz6-May-08 5:20

tibiz

6-May-08 5:20

How is possible to determine, if a drag'n'drop event is active between two other appliactions or processes.

I mean - catching the event globally - that in Windows is at the moment a drag'n'drop event in progress.

Thanx a lot

tibiZ.net homepage

Copy files with out using SHFileOperation

itsh116-May-08 5:11

itsh11

6-May-08 5:11

I want to copy (large)files from one location to the other but I am having problems with SHFileOperation in vista (I cannt cancel the copying operation, my app says Not Responding when i cancel the copying) but seems to work fine in XP. Is there any other way i can copy files, showing a copying progress and allowing the user to cancel the operation, so that I can avoid this problem in vista? Thanks

Re: Copy files with out using SHFileOperation

Rajkumar R6-May-08 5:29

Rajkumar R

6-May-08 5:29

This function has been replaced in Windows Vista by [IFileOperation^]

have a look at copy Item sample [IFileOperation Introduction^]

Re: Copy files with out using SHFileOperation

itsh116-May-08 5:47

itsh11

6-May-08 5:47

I want it to work in XP too. I think IFileOperation is supported only in vista.

Re: Copy files with out using SHFileOperation

David Crow6-May-08 6:01

David Crow

6-May-08 6:01

itsh11 wrote:
I want it to work in XP too. I think IFileOperation is supported only in vista.

So use one or the other depending on the OS.

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

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

Re: Copy files with out using SHFileOperation

David Crow6-May-08 6:00

David Crow

6-May-08 6:00

itsh11 wrote:
Is there any other way i can copy files, showing a copying progress and allowing the user to cancel the operation, so that I can avoid this problem in vista?

What about CopyFileEx()?

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

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

SetFilePointer

john56326-May-08 3:16

john5632

6-May-08 3:16

Hi,

I am passing the offset in SetFilePointer(offset) that does not exist in a file but this function is succedding. If this offset is not exist, it should not succeed.

code is:

<br />
LARGE_INTEGER     largeSector ={NULL};<br />
	largeSector.QuadPart =ullPosition;<br />
<br />
	largeSector.LowPart =SetFilePointer(m_hHandleTOLogicalDrive,largeSector.LowPart,&largeSector.HighPart,FILE_BEGIN);<br />
	if ( largeSector.LowPart==INVALID_SET_FILE_POINTER && (GetLastError())!=NO_ERROR )<br />
	{<br />
		cout<<"unable to set pointer";<br />
		return FALSE;<br />
	}<br />
	else<br />
		return TRUE;<br />

Re: SetFilePointer

CPallini6-May-08 3:23

CPallini

6-May-08 3:23

From MSDN [^]:

It is not an error to set a file pointer to a position beyond the end of the file. The size of the file does not increase until you call the SetEndOfFile, WriteFile, or WriteFileEx function. A write operation increases the size of the file to the file pointer position plus the size of the buffer written, which results in the intervening bytes uninitialized.

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

CList::RemoveAt

piul6-May-08 2:09

piul

6-May-08 2:09

Hello!!
What happens to a CList when using RemoveAt(POSITION) . Does the list re-arrange itself to fill that gap?? If not, how do you do it to remove an internal node?
Does it have to be done manually, remove a node, and then shift the rest of elements one position??

Re: CList::RemoveAt

Nelek6-May-08 2:17

Nelek

6-May-08 2:17

piul wrote:
Does the list re-arrange itself to fill that gap??

Yes and no. The good thing from a List vs an array is (in grosso modo): that every node is pointing to next and previous node. So when you delete one position, you dont have to rearrange anything, just modify 2 pointers the "next" in the previous node and the "previous" in the next node. Then the node in the middle is not in the list anymore and can be just deleted without problems.

piul wrote:
Does it have to be done manually, remove a node, and then shift the rest of elements one position??

You dont have to move anything, a list is not an array.

Greetings.
--------
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
“The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet.” - Michael A. Jackson

Re: CList::RemoveAt

toxcct6-May-08 2:18

toxcct

6-May-08 2:18

thanksfully it does, hey !!!

do you write classes letting the user manage its content himself ? Unsure | :~

BTW, why don't you test it ?

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Re: CList::RemoveAt

Rajesh R Subramanian6-May-08 2:19

Rajesh R Subramanian

6-May-08 2:19

Thankfully it is a list and not an array. Therefore, no shifting of elements is required for a delete operation. It is just changing where a single 'next' pointer is pointing to. For example, if you delete the 3rd element, what internally happens is, the next pointer of the second element points to the 4th element and so the 3rd one is 'dropped'.

A 'C++' question asked in the Visual C++ forum:
Title: please stomuch me
if i have
string s[7];
s[1]="hello"
...
s[7]="how are you"
can i trace s[1] by loop and select specified item as example i, want to select e from s[1]="hello"..... the question is : this process possible or impossible!? I hope help me.......thanks - sofia_111

CPallini6-May-08 2:25

CPallini

6-May-08 2:25

Rajesh R Subramanian wrote:
A 'C++' question asked in the Visual C++ forum:
Title: please stomuch me
if i have
string s[7];
s[1]="hello"
...
s[7]="how are you"
can i trace s[1] by loop and select specified item as example i, want to select e from s[1]="hello"..... the question is : this process possible or impossible!? I hope help me.......thanks - sofia_111

You're really a bad guy. Big Grin | :-D