Re: _wrename ( ) somehow deletes the already existing file in the file system - C / C++ / MFC Discussion Boards

voorugonda prashanth10-Jul-06 19:20

10-Jul-06 19:20

hi all,

how much heap memory allocated for a process?

how much stack memory allocated for a process?

if i have 512MB RAM and trying allocate 1GB of Heap memory what will happen??

please explain or give me links.

Thanks in advance.

Re: Regarding memory

Code_Zombie10-Jul-06 19:39

Code_Zombie

10-Jul-06 19:39

Default heap size is 1mb,this can be changed using the /heap linker option.An application can directly use about 2gb
of address space.

Same for stack also,1mb is the default and can be changed using the /stack linker option

Re: Regarding memory

voorugonda prashanth10-Jul-06 20:01

voorugonda prashanth

10-Jul-06 20:01

but what will happen , if i have 512MB RAM and trying to allocate 1GB of heap memory?

please give me the links or suggest any books?

thank u.

Re: Regarding memory

Jonathan [Darka]10-Jul-06 23:16

Jonathan [Darka]

10-Jul-06 23:16

It will attempt to allocate the memory from virtual memory

Darka [Xanya]

Re: Regarding memory

Jun Du11-Jul-06 3:42

Jun Du

11-Jul-06 3:42

BTW, 2GB is for 32-bit Windows, which is the total limit of stack plus heap plus none-user memory.

Best,
Jun

_wrename ( ) somehow deletes the already existing file in the file system

cathy_d'souza10-Jul-06 19:20

cathy_d'souza

10-Jul-06 19:20

I m using _wrename( ) in my VC code.. when i register file in the file system and rename them using _wrename() after performing this many times, the new files are registered correctly and renamed appropriately but somehow the files registered earlier gets deleted from the file system. now each time the new file is registered an d renamed an old file is deleted.. I m unable to track the reason behind this..
Please help me with an appropriate logic behind this..

Thanks in advance..

Re: _wrename ( ) somehow deletes the already existing file in the file system

Parthi_Appu10-Jul-06 21:31

Parthi_Appu

10-Jul-06 21:31

what u r mentioning as old and new file. say their is a file '1.txt' and '2.txt',now rename '1.txt' to 'a.txt', whtz happening? is '2.txt' get deleted now?

Re: _wrename ( ) somehow deletes the already existing file in the file system

cathy_d'souza10-Jul-06 21:35

cathy_d'souza

10-Jul-06 21:35

Parthi_appu wrote:
what u r mentioning as old and new file. say their is a file '1.txt' and '2.txt',now rename '1.txt' to 'a.txt', whtz happening? is '2.txt' get deleted now?

Yes after registering and renamingmany files say 1.pdf,2.pdf,.....200.pdf, now when 201.pdf is registered and renamed some previous file like 10.pdf gets deleted and on subsequent renaming of more files, 11.pdf, 12.pdf and so on gets deleted.

Doubt regarding the Hook

Member 303984310-Jul-06 18:31

Member 3039843

10-Jul-06 18:31

Hi all,
Can any one plz tell me how to set the hook in MFC.
Thanks in advance.

Re: Doubt regarding the Hook

FarPointer10-Jul-06 18:36

FarPointer

10-Jul-06 18:36

Seting the hook using :-
SetWindowsHook
removing the hook:-
UnhookWindowsHook
MSDN and codeproject are having nice article on hooking.

Regards,
FarPointer
Blog:FARPOINTER

Re: Doubt regarding the Hook

Abhi Lahare10-Jul-06 18:37

Abhi Lahare

10-Jul-06 18:37

SetWindowsHookEx().

go thru article on Keyboard Hooking, its a good start

http://www.codeproject.com/dll/keyboardhook.asp[^]

Regards
Abhishake

Re: Doubt regarding the Hook

Code_Zombie10-Jul-06 19:19

Code_Zombie

10-Jul-06 19:19

Hi,

Please go thru the this link for more information on hooks http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/windowing/hooks.asp[^]

Re: Doubt regarding the Hook

Hamid_RT10-Jul-06 20:27

Hamid_RT

10-Jul-06 20:27

See API Hooking Revealed[^]

whitesky

example

thathvamsi10-Jul-06 18:02

thathvamsi

10-Jul-06 18:02

can anyone send some simple examples showing the WM_TIMER implementation?

Re: example

Steve Echols10-Jul-06 18:19

Steve Echols

10-Jul-06 18:19

How about:

http://www.codeproject.com/system/timers_intro.asp[^]

- S
50 cups of coffee and you know it's on!

Re: example

ThatsAlok10-Jul-06 19:09

ThatsAlok

10-Jul-06 19:09

thathvamsi wrote:
n anyone send some simple examples showing the WM_TIMER implementation?

http://www.codeproject.com/audio/mult_media_timer.asp[^] for Multimedia Timer
http://www.codeproject.com/cpp/one_shot.asp[^] for MFC Timer Smile | :)

"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
Support CRY- Child Relief and You

Re: example

Code_Zombie10-Jul-06 19:58

Code_Zombie

10-Jul-06 19:58

Hi,

Try the below sample,

void CMainFrame::OnStartTimer() <br />
{<br />
   m_nTimer = SetTimer(1, 2000, 0);<br />
}<br />
<br />
void CMainFrame::OnStopTimer() <br />
{<br />
   KillTimer(m_nTimer);   <br />
}<br />
<br />
void CMainFrame::OnTimer(UINT nIDEvent) <br />
{<br />
  AfxMessageBox("Timer");	<br />
  CFrameWnd::OnTimer(nIDEvent);<br />
}

Re: example

Hamid_RT10-Jul-06 20:19

Hamid_RT

10-Jul-06 20:19

See example in msdn Here[^]

whitesky

Re: example

thathvamsi10-Jul-06 20:31

thathvamsi

10-Jul-06 20:31

Thanks for that.
For my application, can I use the following
Is this correct way of doing?

On_send(wparam,lparam)
{
//packet sent to serial device
//timer has to be triggered on here
SetTimer();

}

On_rx(wparam,lparam)
{
//checks for packet received
//if no packet received from serial device, then
{
//check for timer has elapsed
OnTimer()
{
//resend the packet to MPU
post_message(WM_RESEND,null)
}

}
}

On_resend(wparam,lparam)
{
//send same packet to PC
here, I have to restart the timer again to see if the
serial device responded within particular time as in On_rx.
KillTimer();
SetTimer();
}

What more do I need to add?

Re: example

ThatsAlok10-Jul-06 22:50

ThatsAlok

10-Jul-06 22:50

timer will call itself, you don't need to call that function!

"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
Support CRY- Child Relief and You

Derived class from abstract class(COleControl in MFC) gave error while allocation memory

dashprasannajit10-Jul-06 17:31

dashprasannajit

10-Jul-06 17:31

Created a class i.e. CFlipCustomViewer derived from COleConrol class(abstact class)and
overridden the "virtual void OnDraw(CDC* pdc, const CRect& rcBounds, const CRect& rcInvalid)" method of COleControl class in the void CFlipCustomViewer::OnDraw(CDC* pdc, const CRect& rcBounds, const CRect& rcInvalid).I tried to call this in OnInitDialog() method of my dialog class of the application.Here the code snippets..

BOOL CFlip::OnInitDialog()
{
//having a CStatic as a place holder and then
//create the flip custom control in InitDialog

COleControl* ptrOleControl; //abstract base class pointer
CFlipCustomViewer* ptrFlipCustomViewer; //derived class pointer
ptrOleControl = ptrFlipCustomViewer; //derived class pointer assigned to abstract base class pointer
ptrOleControl = new CFlipCustomViewer(); //error in this instantiation of derived one
CDC* pdc = GetDC(); //get the device context
CRect rcBounds;
CRect rcInvalid;
GetClientRect( &rcBounds);
GetClientRect( &rcInvalid);
ptrOleControl->OnDraw(pdc,rcBounds,rcInvalid);//place holder for flipping action
CDialog::OnInitDialog();
return TRUE;
}
****************************************************************************************
but while compiling i am getting the following errors as below :
error C2259: 'CFlipCustomViewer' : cannot instantiate abstract class due to following members:
d:\fancyviewer\flipsample\flipcustomviewer.h(14) : see declaration of 'CFlipCustomViewer'
d:\fancyviewer\flipsample\flip.cpp(200) : warning C4259: 'long __thiscall COleControl::GetClassID(struct _GUID *)' : pure virtual function was not defined
d:\program files\microsoft visual studio\vc98\mfc\include\afxctl.h(683) : see declaration of 'GetClassID'
d:\fancyviewer\flipsample\flip.cpp(200) : warning C4259: 'unsigned int __thiscall COleControl::GetUserTypeNameID(void)' : pure virtual function was not defined
d:\program files\microsoft visual studio\vc98\mfc\include\afxctl.h(936) : see declaration of 'GetUserTypeNameID'
d:\fancyviewer\flipsample\flip.cpp(200) : warning C4259: 'unsigned long __thiscall COleControl::GetMiscStatus(void)' : pure virtual function was not defined
d:\program files\microsoft visual studio\vc98\mfc\include\afxctl.h(937) : see declaration of 'GetMiscStatus'
d:\fancyviewer\flipsample\flip.cpp(200) : error C2259: 'CFlipCustomViewer' : cannot instantiate abstract class due to following members:
d:\fancyviewer\flipsample\flipcustomviewer.h(14) : see declaration of 'CFlipCustomViewer'
****************************************************************************************

Can anyone helpme out please ?

Re: Derived class from abstract class(COleControl in MFC) gave error while allocation memory

Steve Echols10-Jul-06 18:29

Steve Echols

10-Jul-06 18:29

You need to override all the pure virtual functions of an abstract base class, but why not just derive from from CWnd instead?

- S
50 cups of coffee and you know it's on!

[Noob question] Reading a file gives me weird Y chars?

Lord Kixdemp10-Jul-06 16:19

Lord Kixdemp

10-Jul-06 16:19

Hello everyone!
Look at my code:

int Interface::InitScreen()<br />
{<br />
    // Open main UI screen<br />
    ifstream mainUIScreen((string(".\\") + string(DIR_SCREENS) + string("mainui.asc")).c_str());<br />
    ofstream mainUIScreen_Edit((string(".\\") + string(DIR_SCREENS) + string("mainui_edited.asc")).c_str());<br />
<br />
    // Exit if on error<br />
    if (!mainUIScreen.is_open())<br />
    {<br />
        MessageBox(NULL, "Cannot open program file 'mainui.asc'!", "Error",<br />
            MB_OK | MB_ICONEXCLAMATION);<br />
        exit(-1);<br />
    }<br />
<br />
    // Exit if on error<br />
    if (!mainUIScreen.good())<br />
    {<br />
        MessageBox(NULL, "Cannot open program file 'mainui.asc'!", "Error",<br />
            MB_OK | MB_ICONEXCLAMATION);<br />
        exit(-1);<br />
    }<br />
<br />
    char c;<br />
    for (int x = 0; x < WIDTH*HEIGHT; x++)<br />
    {<br />
        c = mainUIScreen.peek();<br />
        mainUIScreen_Edit.put(c);<br />
    }

When I open the output file (mainui_edited.asc), I get a bunch of 0x98's instead of the chars I want... Why is that? Thanks!

Windows Calculator told me I will die at 28. Frown | :(

Re: [Noob question] Reading a file gives me weird Y chars?

Lord Kixdemp13-Jul-06 11:51

Lord Kixdemp

13-Jul-06 11:51

To anyone that reads this: I was using an Unicode file... Mad | :mad:

Windows Calculator told me I will die at 28. Frown | :(

timer for 1sec and more

thathvamsi10-Jul-06 15:32

thathvamsi

10-Jul-06 15:32

Hey all,
In my application, I need to turn on the timer once the Pc sends a packet to the serial device. the serial device should respond immediately to teh PC's request. The Pc should get response from the serial device within "m" secs. the Pc will wait for response from serial device and check for the timer. if elapsed, will resend the packet again.

in brief,

On_send(wparam,lparam)
{
//packet sent to serial device
//timer has to be triggered on here
}

On_rx(wparam,lparam)
{
//checks for packet received
//if no packet received from serial device, then
{
//check for timer
while(timer has elapsed)
{
//resend the packet to MPU
post_message(WM_RESEND,null)
}
}
}

On_resend(wparam,lparam)
{
//send same packet to PC
here, I have to restart the timer again to see if the
serial device responded within particular time as in On_rx.
}

this is the idea i have in mind. but i dont know how to implement. Can I use WM_TIMER...? I know there are various timers like multimedai timers, etc., But dont know which one suits my need as I am still in the learning curve of MFC.

I would appreciate if anyone can help me with this.
Thanks in advance.

----
This was my query that I posted yesterday for which I got solutions that WM_TIMER and SetTimer() would be best option.

But doesnt the timer posts the WM_TIMER message to the message queue and we can not be sure when this message will be processed. If that is the case, then how can I use this for my application.?

any help?

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