C / C++ / MFC Discussion Boards

Re: check existence of file in C++

Stuart Dootson22-Feb-09 13:48

Stuart Dootson

22-Feb-09 13:48

The standard way of checking file existence on *nix (it works on Windows as well) is stat or fstat[^], I believe.

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

Re: check existence of file in C++

meixiang622-Feb-09 16:29

meixiang6

22-Feb-09 16:29

I will give it a try tommorrow...thanks!

Re: check existence of file in C++

Dan22-Feb-09 21:25

Dan

22-Feb-09 21:25

You can also try in Windows,

if ( 0 == _access( database.c_str(), 0 ) ) {
     cout<<"No database found.\n"
}

and the nix equivelant is

 if ( 0 == access( database.c_str(), 0 ) ) {
    cout<<"No database found.\n"
}

How to check whether system is connected to internet using VC++?

Supra221-Feb-09 3:02

Supra2

21-Feb-09 3:02

Hi,
I have a requirement where I need to find out whether internet is available or not. How to achieve this using VC++?

THanks
Suhas

Re: How to check whether system is connected to internet using VC++?

Iain Clarke, Warrior Programmer21-Feb-09 11:46

Iain Clarke, Warrior Programmer

21-Feb-09 11:46

You can use InternetGetConnectedState (http://msdn.microsoft.com/en-us/library/aa384702(VS.85).aspx[^]) to check whether you *might* be connected - but the only guarantee is to attempt a connection to your desired website.

Iain.

Codeproject MVP for C++, I can't believe it's for my lounge posts...

Re: How to check whether system is connected to internet using VC++?

David Crow21-Feb-09 14:35

David Crow

21-Feb-09 14:35

Supra2 wrote:
How to achieve this using VC++?

See here.

"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown

"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

how do i read the files from executable file?

balukk21-Feb-09 2:17

balukk

21-Feb-09 2:17

i need a help to read files in the .exe file. help me to solve this problem.

Re: how do i read the files from executable file?

Iain Clarke, Warrior Programmer21-Feb-09 2:25

Iain Clarke, Warrior Programmer

21-Feb-09 2:25

FindResource
LockResource
etc

Iain.

Codeproject MVP for C++, I can't believe it's for my lounge posts...

Re: how do i read the files from executable file?

David Crow21-Feb-09 14:36

David Crow

21-Feb-09 14:36

Read files that are in the EXE (as a resource), or read files using an EXE?

OnCtlColor not working fine in case of PropertyPage.

Le@rner21-Feb-09 0:42

Le@rner

21-Feb-09 0:42

Hi all,

i m write code on OnCtlColor function for color the controls.

HBRUSH CMyPropertyPage2::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)
{
	HBRUSH hbr = CPropertyPage::OnCtlColor(pDC, pWnd, nCtlColor);

	switch (nCtlColor)
	{
		case CTLCOLOR_EDIT:
			pDC->SetTextColor(RGB(0,0,0));
			pDC->SetBkColor(RGB(255,255,255));
			return hbr;

		case CTLCOLOR_STATIC:
			
			LOGBRUSH logbrush;
			m_brush.GetLogBrush( &logbrush );
			pDC->SetTextColor(RGB(0,0,0));
			pDC->SetBkColor(logbrush.lbColor);
			return m_brush;
			

		case CTLCOLOR_BTN:
		case CTLCOLOR_MSGBOX:
		case CTLCOLOR_DLG:
			return m_brush;
		
		default:
			return m_brush;
	}

}

when i use this same code for dialog box its working fine,but in case of property pages its not working fine.

the problem is that its not color the background of RadioBox,CheckBox,GroupBox type controls.

please help me for this.

and tell me solution for this.

thanks in advance

To accomplish great things, we must not only act, but also dream;
not only plan, but also believe.

Re: OnCtlColor not working fine in case of PropertyPage.

Iain Clarke, Warrior Programmer21-Feb-09 2:28

Iain Clarke, Warrior Programmer

21-Feb-09 2:28

I don;t know the answer to your probklem, but I know where I'd start looking...

Spy++. Keep an eye where the messages go - maybe to the propertysheet, maybe to the propertypage... But you can find out!

Iain.

Codeproject MVP for C++, I can't believe it's for my lounge posts...

Re: OnCtlColor not working fine in case of PropertyPage.

Le@rner23-Feb-09 17:26

Le@rner

23-Feb-09 17:26

Actully i dont understand that you say i have no idea of SPY please explain me.

To accomplish great things, we must not only act, but also dream;
not only plan, but also believe.

Re: OnCtlColor not working fine in case of PropertyPage.

Iain Clarke, Warrior Programmer23-Feb-09 22:11

Iain Clarke, Warrior Programmer

23-Feb-09 22:11

Well, in VC6, it's a program under the tools menu, and it exists in later versions of Visual Studio also.

It monitors messages between windows, so you can see for yourself where messages end up.

(It's called Spy++ - sorry if I misnamed it before).

It takes a little practise to use, but it's very powerful.

Good luck,

Iain.

Codeproject MVP for C++, I can't believe it's for my lounge posts...

Re: OnCtlColor not working fine in case of PropertyPage.

Le@rner23-Feb-09 22:15

Le@rner

23-Feb-09 22:15

i m using VC2005.

thanks.

To accomplish great things, we must not only act, but also dream;
not only plan, but also believe.

Conversion VC++6.0 to VC++.net

Anu_Bala21-Feb-09 0:12

Anu_Bala

21-Feb-09 0:12

Hi,

We have planned to convert the project from VC++6.0 to VC+.net .
But i have no idea about this.
Is there any problem will come by converting or any tutorila is available for this?

Pls help me.

Anu

Re: Conversion VC++6.0 to VC++.net

Gary R. Wheeler21-Feb-09 2:39

Gary R. Wheeler

21-Feb-09 2:39

This[^] blog post on MSDN has links to a number of topics that should help you.

Software Zen: delete this;
Fold With Us![^]

VS2008

rasmirv20-Feb-09 22:39

rasmirv

20-Feb-09 22:39

Is there any articles which help me to connect with a sqlite database using VC2008?
And how will I include dll/lib files to my project?help me.

Re: VS2008

Rajesh R Subramanian21-Feb-09 21:11

Rajesh R Subramanian

21-Feb-09 21:11

CodeProject has a Database articles section (hidden on the "Chapters" pane on the left side...)

It is a crappy thing, but it's life -^ Carlo Pallini

how to display Images in ListBox Rows. [modified]

hemlat20-Feb-09 22:22

hemlat

20-Feb-09 22:22

Hi,
I am able to display Images in Lisbox one by one in single column.I want to Display Images as rows and columns.Can anyone suggest me how to do it.

Rekha.

modified on Saturday, February 21, 2009 4:43 AM

Re: how to display Images in ListBox Rows.

Gary R. Wheeler21-Feb-09 2:41

Gary R. Wheeler

21-Feb-09 2:41

A list control (CListCtrl[^] in MFC) is much easier to use for that purpose.

Software Zen: delete this;
Fold With Us![^]

Re: how to display Images in ListBox Rows.

SandipG 21-Feb-09 8:58

SandipG

21-Feb-09 8:58

As already told CListCtrl would be a better choice.
But if you still want to use list box Look here[^]. This link was already given to you for your previous post, doesn't it help?

Regards,
Sandip.

Help requested: "Debug assert failed" with process hang

Andrew McAuley20-Feb-09 22:20

Andrew McAuley

20-Feb-09 22:20

Hi there,
I'm new to C++ and i've got a basic project i've made up, just to play around with templates. It consists of the following classes:

- enumerable (used much like IEnumerable in .NEt Framework code)
- list<Type> [inherits from enumerable] (provides basic add & remove alongside initial sizes)

- keyValuePair<KeyType, ValueType> (is a simple struct with 2 properties - key and value...

- dictionary<KeyType, ValueType> [inherits from list] (is a list, which uses keyValuePair

No error appears to occur until the end of my program exection. At this point the program simply hangs while executing my final instruction:

delete [] pDict;

My program currently does something no more complex than adding a few initial items to a dictionary, retrieving a list object filled with keys and then cleaning up... So I pause the debugger, it warns me:

The process appears to be deadlocked (or is not running any user-mode code). All threads have been stopped.

and it then points me to:

dbgrpt.c (line 360 - 363):

/* Report the warning/error */
 nCode = __crtMessageBox(szOutMessage,
                      _T("Microsoft Visual C++ Debug Library"),
                      MB_TASKMODAL|MB_ICONHAND|MB_ABORTRETRYIGNORE|MB_SETFOREGROUND);

and points out that the line containing _T("Mi... is where the error occured. As far as i can understand, this portion of the "dbgprt.c" file displays an assertion failed error message. In case that helps any:

szOutMessage = "Debug Assertion Failed!
   Program: ...iversity for the West of Scotland\Samples\Debug\Templates.exe
   File: f:\dd\vctools\crt_bld\self_x86\crt\src\dbgdel.cppLine: 52
   Expression: _BLOCK_TYPE_IS_VALID(pHead-&gt;nBlockUse)
   For information on how your program can cause an assertion
   failure, see the Visual C++ documentation on asserts.
   (Press Retry to debug the application)";

I then proceded to search MSDN documentation and found nothing specific to help me... Unfortunately searches of this forum didn't help me get any further so here is my question:

Where should I look? and what should I be looking for as possible sources of the error?

I've checked for un-initialised variables, memory leaks, and ensured (i think) all functions that return a value have a variable to be copied into so as to clean the stack... and so far all seems fine.

Thankyou for reading.

Re: Help requested: "Debug assert failed" with process hang

Gary R. Wheeler21-Feb-09 2:48

Gary R. Wheeler

21-Feb-09 2:48

First question: Was pDict allocated as an array, i.e.

pDict = new pDictType[size];

You are using the array delete syntax (delete []pDict). If pDict is a simple pointer, then using the array delete will Do Bad Things.

Other than that, the general things I can suggest are to step through the code and ensure that you're not walking over something in the stack. The symptom you are describing (all threads exited) sounds like a stack overwrite.

Software Zen: delete this;
Fold With Us![^]

Re: Help requested: "Debug assert failed" with process hang

Andrew McAuley21-Feb-09 7:53

Andrew McAuley

21-Feb-09 7:53

Thanks for the resonse (and sorry about the delay) Yes, pDict was initialised as an array.

would you know of any areas or topics I might want to look into to refrence, or is it purely experience and luck :p

Re: Help requested: "Debug assert failed" with process hang

Gary R. Wheeler21-Feb-09 9:24

Gary R. Wheeler

21-Feb-09 9:24

If the program is simple (your description made it sound like that was the case), single-stepping through it and verifying that each statement does exactly what you think it does is a valid approach. Look for side effects, possible buffer overruns, and things like that.

Barring that, you might post some of the code here, and let us have a look, if it's not horribly lengthy.

The STL container classes can occasionally be a double-edged sword. They are very capable, but I've seen folks do some foolhardy things with them (think void pointers, up and down casts, and that sort of thing).

Software Zen: delete this;
Fold With Us![^]

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