C / C++ / MFC

Re: system call too small

16-Jan-10 7:57

DavidCrow wrote:
First, CreateFile() is not a boolean function

Good point, indeed. 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

[My articles]

2buck5616-Jan-10 11:01

2buck56

16-Jan-10 11:01

Richard this is the code for DisplayLastError:

void CHIDTest2008Dlg::DisplayLastError(CString Operation)
{
//Display a message and the last error in the log List Box.
	LPVOID lpMsgBuf;
	USHORT Index = 0;
	CString	strLastError;
	FormatMessage( 
		FORMAT_MESSAGE_ALLOCATE_BUFFER | 
		FORMAT_MESSAGE_FROM_SYSTEM | 
		FORMAT_MESSAGE_IGNORE_INSERTS,
		NULL,
		GetLastError(),
		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
		(LPTSTR) &lpMsgBuf,
		4096,
		NULL 
	);

	//Display the last error.
	strLastError = Operation + (LPCTSTR)lpMsgBuf; 

	//Trim CR/LF from the error message.
	strLastError.TrimRight(); 
	Index = m_ResultsList.InsertString(-1, strLastError);
	ScrollToBottomOfListBox(Index);
	LocalFree(lpMsgBuf);

And I believe you are correct in saying that the CString cast is causing the error. If I call GetLastError immediately after entering my OnBnClick funtion I get the error. At that point no API call has been made (other than the ones the system is doing). Also, by turning off unicode and going to MBCS, all the error messages disappeared. That points to the CString cast.

Ian, the code you show is the way I am doing it now. Since none of my API calls are failing I am not getting any error messages.

Default path to Desktop with vista

dbell0715-Jan-10 9:52

dbell07

15-Jan-10 9:52

Hi everyone. I'm a newbee that's exhausted the Internet already, so I joined the forum.

I'm attempting to create a file on the Desktop under the Vista environment, which is not user dependent. e.g

ofstream file;
file.open("c:\\%userprofile%\\Desktop\\report.txt");
if (!file){
cerr <<"Unable to open file report.txt";
exit(1);
}

but cannot seem to make this happen on the c drive (desktop).
Thanks in advance.

CoderGirl4215-Jan-10 10:18

CoderGirl42

15-Jan-10 10:18

You should be able to just call %userprofile%\desktop without having the c:\ at the front. if you open your command prompt and type in %userprofile% it'll then give you an error message but it will expand the %userprofile% to it's actual value.

Hope that helps

David Crow15-Jan-10 10:25

David Crow

15-Jan-10 10:25

CoderGirl42 wrote:
...but it will expand the %userprofile% to it's actual value.

Unless it contains spaces.

"One man's wage rise is another man's price increase." - Harold Wilson

"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

dbell0715-Jan-10 10:46

dbell07

15-Jan-10 10:46

I see the expansion in which you are speaking of from the cmd window. However, since %userprofile% yields the msg. "...' is not recognized as an internal or external command, operable program or batch file.", I'm wondering if this is the same reason %userprofile% does not work from within my program. I'm beginning to think it's the vista platform Cry | :((

dbell0715-Jan-10 10:49

dbell07

15-Jan-10 10:49

Yes, I've tried various forms... e.g. without c:\ without success...

Rozis16-Jan-10 10:28

Rozis

16-Jan-10 10:28

Maybe stupid but if you open a DOS-window and type in SET (enter) is your userprofile there?

Rozis

Showing and Closing Dialogs in C++

Spawn@Melmac18-Jan-10 0:35

Spawn@Melmac

18-Jan-10 0:35

Sorry to say this but I believe you are misunderstanding the use of environment variables.

Apart from the fact that the string you are using is wrong ( the variable already contains the drive letter and as already pointed out may contain spaces) do you know the call you are making with apply environment variable expansion?

I prefer not to leave things to chance by either calling,

ExpandEnvironmentStringsForUser - "http://msdn.microsoft.com/en-us/library/bb762275(VS.85).aspx"

or

SHGetFolderPath - "http://msdn.microsoft.com/en-us/library/bb762181(VS.85).aspx"

Alan

NightBeforeChirstmas15-Jan-10 9:29

NightBeforeChirstmas

15-Jan-10 9:29

I am trying to build a application consists of four dialogs(Dialog A, dialog B, Dialog C and Dialog D).

In dialog A is you press next button it will go to dialog B, at dialog B if you press cancel button it will go back to dialog A. If next button of dialog B is clicked then it will proceed to dialog C and so on.
For the last dialog, Dialog D, if the Finish button is clicked, it will go back to dialog A.

How can I link all the dialogs to work in the sequence specified.
Should I add dialog B,C,D as custom dialog to dialog A?

In dialog A I wrote the code shown below.where is member variable of CtryDlg which declared as CBDlg type.

/*tryDlg.cpp*/
#include "BDlg.h"

void CtryDlg::OnNext()
{
int nRet = m_dBDlg.modal();

}

In dialog B,

void CBDlg::OnCancelB()
{
int nRet = 5;
EndDialog(nRet);
return;
}

But I keep getting Debug Assertion Failed error when the next button of Dialog A is clicked.
Can someone give me so suggestions?

Thanks.

Re: Showing and Closing Dialogs in C++

Maximilien15-Jan-10 9:31

Maximilien

15-Jan-10 9:31

Can't you use a CPropertySheet in Wizard mode to do this ?

see : http://msdn.microsoft.com/en-us/library/d3fkt014%28VS.80%29.aspx[^]

M.

This signature was proudly tested on animals.

Re: Showing and Closing Dialogs in C++

David Crow15-Jan-10 9:48

David Crow

15-Jan-10 9:48

If you can use Maximilien's suggestion, override CPropertyPage::OnWizardFinish() and return FALSE to keep the sheet open. Then call the sheet's SetActivePage() method.

Re: Showing and Closing Dialogs in C++

Bram van Kampen17-Jan-10 6:35

Bram van Kampen

17-Jan-10 6:35

Run it in an External Function:

{
label1:
    DlgA dlga;
    if(dlga.DoModal()==IDCANCEL)return;

label2:
    DlgB dlgb;
    if(dlgb.DoModal()==IDCANCEL)goto label1;

label3:
    DlgC dlgc;
    if(dlgc.DoModal()==IDCANCEL)goto label2;

etc..
}

Regards,

Bram van Kampen

Retrieving Windows version, then enumerating process list

int_8015-Jan-10 5:49

int_80

15-Jan-10 5:49

I need to find out what version of windows is running - Vista/Win7/XP and then get a list of processes. So far, for the list of processes I've got this:

bool isRunning(std::string pName) 
{
	unsigned long aProcesses[1024], cbNeeded, cProcesses;
	if(!EnumProcesses(aProcesses, sizeof(aProcesses), &cbNeeded))
		return false;

	cProcesses = cbNeeded / sizeof(unsigned long);
	for(unsigned int i = 0; i < cProcesses; i++)
	{
		if(aProcesses[i] == 0)
			continue;
		HANDLE hProcess = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, 0, aProcesses[i]);
		char buffer[50];
		GetModuleBaseName(hProcess, 0, buffer, 50);
		CloseHandle(hProcess);

		if(pName == std::string(buffer))
			return true;
	}
	return false;
}

This is supposed to get a list of processes, then return true if process X is running. But in Windows 7 it never returns true. Developing cross platform code for windows machines is getting as bad as Linux now. I'm fairly new to windows coding and I'm finding it nightmarish.

Thanks in advance.

Re: Retrieving Windows version, then enumerating process list

David Crow15-Jan-10 7:53

David Crow

15-Jan-10 7:53

int_80 wrote:
if(pName == std::string(buffer))

Have you set a breakpoint on this statement to see the value of pName and buffer? Maybe it's an upper/lower case issue.

Re: Retrieving Windows version, then enumerating process list

CPallini15-Jan-10 11:06

how to draw a graph on 2 axes in a window

15-Jan-10 11:06

I made a test, on Windows 7 of your code. For some processes the OpenProcess call fails, reporting 5 ('Access denied') as GetLastError return value. For the remaining processes, it works fine (e.g. I can detect the notepad.exe process running).

BTW: while the documentation states that OpenProcess and GetModuleBaseName are provided by Kernel32.lib on Windows 7, I had to link instead with Psapi.lib in order to obtain the executable).

BTW2: I'm the administrator of the machine.
Smile | :)

N Vamshi Krishna15-Jan-10 5:39

N Vamshi Krishna

15-Jan-10 5:39

I want to draw a graph of x and y axes from the middle of the window as origin can
any body help me?

regards

CPallini15-Jan-10 5:51

15-Jan-10 5:51

What is your doubt about?
You've to handle the WM_PAINT message (or implement the OnPaint message handler , if you're using MFC) in order to draw in your window client area, see, for instance: "Using the WM_PAINT Message".
Smile | :)

N Vamshi Krishna15-Jan-10 6:10

N Vamshi Krishna

15-Jan-10 6:10

let me use any CDC, I want to plot on x axis values in time for particular range say
a 10 sec duration and on y axis i want the magnitude which is read from a file.

thanks

CPallini15-Jan-10 6:33

15-Jan-10 6:33

Basically You have to do some scaling to map your values into window client area pixels. Once you've properly scaled points, is just a matter of calling, multiple times, the CDC::LineTo method. Have a look at wonderful Cédric article: "High-speed Charting Control".
Smile | :)

Cedric Moonen15-Jan-10 7:29

Cedric Moonen

15-Jan-10 7:29

Thanks for the nice comment Blush | :O

And by the way, congrats for a well deserved MVP award Wink | ;)

Cédric Moonen
Software developer

Charting control [v3.0 - Updated]
OpenGL game tutorial in C++

CPallini15-Jan-10 7:45