Re: retruning NULL in Handle - C / C++ / MFC Discussion Boards

Y_Kaushik15-Jun-07 0:12

15-Jun-07 0:12

When i used this code

cfile_object.Open("zetaproducer.txt", CFile::modeRead | CFile::shareDenyWrite);

cfile_object.ReadString(strLine);
buffer += strLine + "\r\n";
text->SetWindowText( buffer );
MessageBox(buffer););

An blank MessageBox Show . Mense data can not be read.

Although my actual requirment is to save file in a folder suppose folder name is DOCFile in same folder ( In which my project)

I am not Understang where i am making Wrong

Regard's
Kaushik

Re: Assertion occur when data saving

Mark Salsbery15-Jun-07 5:48

Mark Salsbery

15-Jun-07 5:48

Is cfile_object a CStdioFile object? If so you could also add the CFile::typeText flag, although
if you don't specify CFile::typeBinary, CFile::typeText is the default.

For your requirement, you'll need to specify the full pathname of the file:

cfile_object.Open("driveletter:\\path\\DOCFile\zetaproducer.txt", CFile::modeRead | CFile::shareDenyWrite);

Also make sure Open() returns TRUE before trying to read from the file.

Mark

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

Re: Assertion occur when data saving

Hamid_RT14-Jun-07 20:14

Hamid_RT

14-Jun-07 20:14

Where you got Assertion occur?

WhiteSky

Re: Assertion occur when data saving

Y_Kaushik15-Jun-07 0:14

Y_Kaushik

15-Jun-07 0:14

When i am writing this code for reading contant of File from disk

cfile_object.Open("zetaproducer.txt", CFile::modeRead | CFile::shareDenyWrite);

cfile_object.ReadString(strLine);
buffer += strLine + "\r\n";
text->SetWindowText( buffer );
MessageBox(buffer);

An blank MessageBox Show . Mense data can not be read.

Although my actual requirment is to save file in a folder suppose folder name is DOCFile in same folder ( In which my project)

I am not Understang where i am making Wrong

Regard's
Kaushik

Regard's
Kaushik

Re: Assertion occur when data saving

Hamid_RT15-Jun-07 2:57

Hamid_RT

15-Jun-07 2:57

I am running your code and it reads first line of file and shows this value on the a messageBox of course on your code needs to path of file did you try with path
and for second part of your question do you wan to copy this file to other place?

WhiteSky

retruning NULL in Handle

neha.agarwal2713-Jun-07 20:58

neha.agarwal27

13-Jun-07 20:58

Hello all,

i am trying to extract the html code of a url. I have written this code

CString str;
	

GetDlgItemText(IDC_EDIT1,str);

DWORD dwLen = _MAX_PATH;

CString sCompareURL;

InternetCanonicalizeUrl(str,sCompareURL.GetBufferSetLength(_MAX_PATH),&dwLen,ICU_BROWSER_MODE);

	HINTERNET Ihandle = InternetOpen("Browser", INTERNET_OPEN_TYPE_PRECONFIG, 
                          NULL, NULL, INTERNET_FLAG_ASYNC);
	
HINTERNET hFile =  InternetOpenUrl(Ihandle,str,NULL,0,0,0);

while(true)
{
	const int MAX_BUFFER_SIZE = 65536;
	unsigned long nSize = 0;
	char szBuffer[MAX_BUFFER_SIZE+1];

	BOOL bRet = InternetReadFile(hFile, szBuffer, MAX_BUFFER_SIZE, &nSize);

	if(!bRet || nSize <= 0)
		break;

	szBuffer[nSize] = '\0';
}

but i m getting null in my hFile handle.
is there something wrong in my code. how could i modify my code.

can anybody help me in this

thanks in advance....

Re: retruning NULL in Handle

Rajkumar R13-Jun-07 21:42

Rajkumar R

13-Jun-07 21:42

Hi,
May be due to "InternetOpen" must be the first function, but here its not.
What the GetLastError and InternetGetLastResponseInfo says after InternetOpenUrl.

Re: retruning NULL in Handle

neha.agarwal2714-Jun-07 0:23

neha.agarwal27

14-Jun-07 0:23

GetLastError() returns 2 for some site but for some site it works fi9...
how to resolve this problem.....

Re: retruning NULL in Handle

Rajkumar R14-Jun-07 19:14

Rajkumar R

14-Jun-07 19:14

GetLastError() 2;ERROR_FILE_NOT_FOUND is the error value,
This works for some site means you get the Handle right?
Then It should be "File not found", html file doesnot exist.

Re: retruning NULL in Handle

Jijo.Raj13-Jun-07 21:54

Jijo.Raj

13-Jun-07 21:54

Hi neha,

The problem may be due to INTERNET_FLAG_ASYNC of InternetOpen(). Remove the flag and try. The code snippet will be as follows,

HINTERNET Ihandle = InternetOpen( "Browser",<br />
				  INTERNET_OPEN_TYPE_PRECONFIG,<br />
				  NULL, <br />
				  NULL, <br />
				  NULL);

Regards,
Jijo.

________________________________

Yesterday is history,
Tomorrow is a mystery,
But today is a present.

Re: retruning NULL in Handle

neha.agarwal2714-Jun-07 0:24

neha.agarwal27

14-Jun-07 0:24

no it doen't make a difference....

Re: retruning NULL in Handle

Jijo.Raj15-Jun-07 1:13

Jijo.Raj

15-Jun-07 1:13

I tried your code snippet in my machine, and it works when i changed so. Thats why suggested that. Please recheck.

________________________________

Yesterday is history,
Tomorrow is a mystery,
But today is a present.

Re: retruning NULL in Handle

David Crow14-Jun-07 2:54

David Crow

14-Jun-07 2:54

Why are you ignoring the return value from both InternetOpen() and InternetOpenUrl()? If either of those fail, stop and figure out why. Use GetLastError() for this.

"A good athlete is the result of a good and worthy opponent." - David Crow

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

Can't Write Data To COM Port

sungtany13-Jun-07 20:53

sungtany

13-Jun-07 20:53

I Used Nonoverlapped I/O Serial Communications Because Of Converting to WIN CE

<br />
OpenPort()<br />
{<br />
m_hCOM =  ::CreateFile( m_szCOMPort,											GENERIC_READ | GENERIC_WRITE,					<br />
			0,												NULL,												OPEN_ALWAYS,											NULL,	<br />
			NULL);<br />
<br />
...<br />
...<br />
...<br />
<br />
m_hThread = ::CreateThread(NULL, 0, ThreadRcv, this, 0, &dwThreadID);<br />
}<br />

When A COM PORT is opened I created A Thread For Receving Response Data

<br />
DWORD WINAPI CSerialComm::ThreadRcv(void* arg)<br />
{<br />
  CSerialComm *pCom = (CSerialComm*)(arg);<br />
  <br />
  if ( !SetCommMask(pCom->m_hCOM, EV_RXCHAR) )<br />
	return 0;<br />
  while( pCom->m_bConnected == TRUE )<br />
  {<br />
    if ( WaitCommEvent(pCom->m_hCOM, &dwRcvEvent, NULL) )<br />
    {<br />
       .......<br />
    }<br />
  }<br />
  ....<br />
<br />
  return 0;<br />
}<br />

But While ThreadRcv is running( Blocked WaitCommEvent Func ), Any attempt to send Data To COM

PORT doesn't work. ( Blocked In WriteFile(...) )

HELP ME~ plz Cry | :((

Re: Can't Write Data To COM Port

Roger Stoltz13-Jun-07 23:17

Roger Stoltz

13-Jun-07 23:17

sungtany wrote:
But While ThreadRcv is running( Blocked WaitCommEvent Func ), Any attempt to send Data To COM PORT doesn't work. ( Blocked In WriteFile(...) )

Of course, since you're not using overlapped I/O.
If you don't use overlapped I/O the driver only handles one IRP at a time, which means e.g. that a write operation will block while waiting for a read operation to timeout.
In this case it is essential that you set the COMMTIMEOUTS to make a read operation timeout within a time frame that suits your needs.

I would try the following:
Spawn a worker thread that read data from queue containing data to be sent.
The worker thread would examine the queue if it contains data it would be sent.
Issue a read operation that will eventually time out, the read data should be put in a queue containing received data and the main thread should be notified with a user defined message that some data has been received. Then the main thread can extract the read data from the queue and do whatever needs to be done with the data.

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

Re: Can't Write Data To COM Port

sungtany14-Jun-07 3:31

sungtany

14-Jun-07 3:31

Thanks I'll try your comments

Warnings

tom groezer13-Jun-07 20:18

tom groezer

13-Jun-07 20:18

How do I convert _tcscpy to _tcscpy_s in Visual Studio 2005. i need to do this to remove the warnings.

Re: Warnings

Paresh Chitte13-Jun-07 20:51

Paresh Chitte

13-Jun-07 20:51

You could use "Find Replace" utility. Smile | :)

Q. Or do you want to suppress the warning ?
A. For suppressing the warning you could use

#pragma warning(disable: WarningNumber)

Regards,

Paresh.

Re: Warnings

BadKarma13-Jun-07 20:55

BadKarma

13-Jun-07 20:55

The pending is stands for Secure. Its a protection build in to prevent buffer overruns.
You just need to give the size of the destination buffer.
See help. Clickety[^]

codito ergo sum

Re: Warnings

prasad_som13-Jun-07 21:13

prasad_som

13-Jun-07 21:13

tom groezer wrote:
How do I convert _tcscpy to _tcscpy_s

You don't need to convert. You need to use secured version advised by the compiler.

Refer Security Enhancement in CRT[^] for more information.

Prasad
MS MVP - VC++

video recording using directX SDK

tyagineha13-Jun-07 18:44

tyagineha

13-Jun-07 18:44

tell me how shld i start to mak a project which displays video from camera(not webcam)using DirectX sdk....

NT

Re: video recording using directX SDK

Hamid_RT13-Jun-07 19:30

Hamid_RT

13-Jun-07 19:30

Did you see DirectX section on the codeproject?

WhiteSky

flushing page file

vasu_sri13-Jun-07 18:35

vasu_sri

13-Jun-07 18:35

I am working on a project where i have to generate a lot of image files. While i am doing this, the size of the page file increases such that i run out of memory. I am thinking of flushing page file at certain intervals but not sure if its the right idea. I am not even sure if it is possible to do it programatically. Is there anyway to programatically flush the page file??

Regards,
Srinivas

Re: flushing page file

SandipG 13-Jun-07 18:43

SandipG

13-Jun-07 18:43

I dont think its good idea i dont even think it would be posible. page file will be automaticly flushed when you will delete your in memory images. if you still have images in memory loaded and flush page file you will be in trouble bro because when you will access image it would try to load from pagefile and there you wont find anything.

How to Enable the menu item

vikramkarthik13-Jun-07 18:21

vikramkarthik

13-Jun-07 18:21

Hello to every one..
my question is i have a menu bar in that two menus im keeping..
1. test
2.execute

In the above test menu i have some menu items..
while im executing ,my test menu items alone should be enabled.Rest sholud be in disabled state..
if i click first menu item , from the test it should automatically enable the next menu items of execute ..
plz help me..
vikram..

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