ATL / WTL / STL

9-Jun-13 3:54

Cool.
Thank you.

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

bkelly139-Jun-13 6:11

9-Jun-13 6:11

Oops, I have a follow up on this.
Declarations:

CSS

CFileException     get_error_message;
 const unsigned int ERROR_MAX = 64;
 char  char_error_text[ ERROR_MAX ];
 LPTSTR ptr_error_text = &char_error_text[0];
 CString final_error_message = "";

Code:

m_definition_file_name += "x";
try
{
   m_definition_file.Open( m_definition_file_name, CFile::modeRead );
   get_error_message.GetErrorMessage( ptr_error_text, ERROR_MAX, NULL );
   final_error_message = char_error_text;
   error_number = GetLastError();

}
catch( CFileException e )
{ code }
catch( ... )
{ code }
{

The line m_definition_file_name += "x" forces the file name to be incorrect.

Char array char_error_text winds up with "No error occurred." while error_number gets 0 (zero)
When the line error_number = GetLastErrror is moved directly beneath the open command, it get the value 2 (two). But that consumes the last error and get_error_message does not get anything.
Nothing is thrown and neither catch is activated.

What do I need to change to use this CFileException?

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

Richard MacCutchan9-Jun-13 9:23

9-Jun-13 9:23

I don't understand what you are doing here; it should be:

C++

try
{
   // code to open the CFile
}
catch (CFileException ce)
{
    TCHAR message[132];
    if (ce.GetErrorMessage(message, 132, NULL)
    {
        // display the contents of the message buffer
    }
}

Use the best guess

bkelly139-Jun-13 9:43

9-Jun-13 9:43

Hello,
I don't see what you have different. Second, when the file does not exist, this Open method does not throw an exception, so none of the try/catch matters. I had a catch(...) at the bottom and it was not entered.

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

Richard MacCutchan9-Jun-13 20:41

9-Jun-13 20:41

If the open function does not throw an error then you need to check the return value and call GetLastError() to find out why, as described here[^]. Alternatively you can throw a new exception like:

C++

try
{
   if (!m_definition_file.Open(m_definition_file_name, CFile::modeRead))
   {
       DWORD error_number = GetLastError();
       throw new CFileException::OsErrorToException(error_number);
   }
}
catch( CFileException e )
{
    // handle the exception
}

Note that when calling GetLastError() you must call it immediately after the failing API function call, otherwise its return may not be valid.

Use the best guess

tried FormatMessage()

bkelly139-Jun-13 7:07

Still looking for reason text

9-Jun-13 7:07

I have also tried this.
Declarations:

CSS

const unsigned int ERROR_MAX = 64;
char  char_error_text[ ERROR_MAX ];
LPTSTR ptr_error_text = &char_error_text[0];
CString final_error_message = "";

With this code

m_definition_file.Open( m_definition_file_name, CFile::modeRead );
error_number = GetLastError();
format_message_return = FormatMessage(  0,              // dwFlags
                                        NULL,           // lpSousrce
                                        error_number,   // dwMessageID
                                        NULL,           // dwLanguageId
                                        ptr_error_text, // lpBuffer
                                        ERROR_MAX,      // nSize
                                        NULL     );     // Arguments
final_error_message = char_error_text;

The error number is 2 (two). char_error_text ends up with nothing. I am uncertain of the arguments for FormatMessage. The file name is forced to be incorrect and an error is expected.

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

bkelly1322-Jun-13 12:17

Re: Still looking for reason text

22-Jun-13 12:17

I have yet to get a text based error code for opening a file. Here is the simplified code:

C++

m_definition_file_name = Select_Definition_File.GetPathName();
m_definition_file_name += "x";  // make the file name bad
m_definition_file.Open( m_definition_file_name, CFile::modeRead );

//  error_number = GetLastError();  // restore to verify error code is 2
get_error_message.GetErrorMessage( ptr_error_text, ERROR_MAX, NULL );
final_error_message = char_error_text;  // says no error

The Open method does not throw an exception. When GetLasError() is used, the error code is 2 (two).
The GetErrorMesssage yields No error returned, which is incorrect. The file could not be opened because it does not exist.

GetErrorMessage(...) is has three arguments about formatting the error message, but the error message is not an argument. I presume it gets the error message like GetLastError() does, but this appears incorrect.

How do I get a text string describing this error?

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

Richard MacCutchan23-Jun-13 0:51

Re: Still looking for reason text

23-Jun-13 0:51

I gave you a suggested solution at http://www.codeproject.com/Messages/4583835/Re-CFileException-discover-reasons.aspx[^], which should throw an exception whose value would be CFileException::fileNotFound (error code 2). Did you try it, and if so what result did you get?

In response to your comment about FormatMessage, you need to tell the function where to look for the mappings of error codes to messages thus:

C++

format_message_return = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM,  // dwFlags
                                        NULL,           // lpSousrce
                                        error_number,   // dwMessageID
                                        NULL,           // dwLanguageId
                                        ptr_error_text, // lpBuffer
                                        ERROR_MAX,      // nSize
                                        NULL     );     // Arguments

This is explained in full detail in the documentation[^].

Use the best guess

bkelly134-Jul-13 11:05

Re: Still looking for reason text

4-Jul-13 11:05

My apologies for no replying sooner. I followed your advice and now have that FormatMessage method working. Thank you.

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

Richard MacCutchan4-Jul-13 20:50

How to force C++ allocate memory from disk?

4-Jul-13 20:50

You're welcome.

Use the best guess

Falconapollo7-Jun-13 23:49

Falconapollo

7-Jun-13 23:49

I have thousands lines of C++ codes which work well on small text files, but crashes on huge text files (such as 2 GB size). Crash reason: app eats up memory.

Is it possible to allocate memory from disk? Because in most case, hard disk space is much bigger than physical memory. If I can borrow some space from hard disk for my app and return them back after use, then my app has little chance to crash.

Here are my design thoughts:

1.Create a temporary file for file mapping(CreateFileMapping, OpenFileMapping)
2.Force my app to allocate memory from the temporary file
3.Do some clean up work: CloseFileMapping and delete the temporary file

Because I have so much existing code, if my design thought is reasonable, I don't want to redesign my project.

I'm not sure if the design thought is possible to implement. Anybody can help me?

PS: I'm using Visual C++ 2010.

Re: How to force C++ allocate memory from disk?

MicroVirus11-Jun-13 0:13

MicroVirus

11-Jun-13 0:13

The most elegant approach is to use MapViewOfFile to only map a smaller piece of the file at any one time, one that does fit into your address space, and then shift the view by Unmap/Map-ing.
In conjunction with this, a way to slightly extend the limit of what can fit in your address space is to set the /LARGEADDRESSAWARE compiler switch, which can be found under the properties. This tells the compiler that you are aware of that 32 bits pointer can use the full range of 0 - 2^32-1, rather than only half that range 2^31-1. With this, you might be able to reach up to ~3GB, depending on system configuration and your application. However, this only slightly shifts the available memory.

Using the above approach, you map the piece of file that you want to use into your address space, and as soon as you are done with the current piece you map the next, etc.

Re: How to force C++ allocate memory from disk?

Falconapollo11-Jun-13 0:19

Falconapollo

11-Jun-13 0:19

thank you for your advice, i will have a try. Smile | :)

Problem when apply cilk_for with ippiFFT of intel parallel

tunheo5-Jun-13 23:37

tunheo

5-Jun-13 23:37

We have a method using ippiFFT to perform forward and inverse FFT of an Image. This method calls ippiFFT 3 times. We try apply cilk_spawn with purpose improve performance of FFT processing, but processing speed of the method is slower than source without cilk_spawn (decreased about 1.5 times). We don't known what is the problem, please help us!

I will describe shortly here:
void performFFT(int start, int end, Ipp32fc[] image)
{
	for(int i = start; i < end; i++)
	{
		ippiFFTInv(Image[i])....
		ippiFFTInv(Image[i])....
		ippiFFTFwd(Image[i])....	
	}
}

Source calls method performFFT without cilk_spawn:

	Image[10];
	performFFT(0, 10, Image);

Source calls method performFFT with cilk_spawn: (which is performance decrease 1.5 times)

	Image[10];
	cilk_spawn performFFT(0,5, Image);
	performFFT(5,10,Image);
	cilk_sync;

Remove COM Objects from VC++ projects

Prashant Gupta 2413-Jun-13 20:05

3-Jun-13 20:05

How to remove COM objects In-placed of regular DLLs in vc++ projects?

Prashant Gupta

Richard MacCutchan3-Jun-13 21:01

3-Jun-13 21:01

Your question is not clear, please explain what problem you are trying to solve.

Use the best guess

Prashant Gupta 2413-Jun-13 22:39

3-Jun-13 22:39

Actually we are implementing a VC++ based application that use few COM objects, COM objects create problem when I think register them(not sure) during compilation.

So we want to replace COM objects by regular DLLs from our application.

I want to know the process that how to remove COM objects.
Wink | ;)

Richard MacCutchan3-Jun-13 22:51

3-Jun-13 22:51

Prashant Gupta 241 wrote:
So we want to replace COM objects by regular DLLs from our application.

I want to know the process that how to remove COM objects.

There is no "process", you just need to rewrite the code where it makes calls to the COM interfaces, such that it uses regular function calls. I am not aware of any simplified method of doing this.

Use the best guess

Prashant Gupta 2413-Jun-13 23:30

3-Jun-13 23:30

Thank Richard

I have one more question
How to identify whether a module is dll or COM objects, so that we can easily identify and remove it.
its little bit confusing for us.

Richard MacCutchan3-Jun-13 23:43

3-Jun-13 23:43

Prashant Gupta 241 wrote:
How to identify whether a module is dll or COM objects

Look at the documentation or source code. Although, you should know that from the implementation in your project.

Use the best guess

Hrpreet singh6-Jun-13 0:36

Hrpreet singh

6-Jun-13 0:36

use inportt and outport commands

Prashant Gupta 2416-Jun-13 0:42