C / C++ / MFC Discussion Boards

Member 75496028-Dec-07 10:42

28-Dec-07 10:42

Re-read the GotW article again. Your issues are addressed in it.

Specifically,

'"...to free resources allocated in the initializer list or in the constructor body!"

Sorry, nope. After all, remember that once you get into your constructor try-block's handler, any local variables in the constructor body are also already out of scope, and you are guaranteed that no base subobjects or member objects exist any more, period. You can't even refer to their names.'

This means p may not be referenced in the exception handler. The object does not exist. The object members do not exist.

Re: Challenging GotW 66's moral

George_George28-Dec-07 19:05

George_George

28-Dec-07 19:05

Hi Member 754960,

I will delete p in the local try block handler and re-throw the exception, other than function try block handler. Do you think this way is ok?

regards,
George

Re: Challenging GotW 66's moral

Member 75496028-Dec-07 20:32

Member 754960

28-Dec-07 20:32

Rethrowing the exception is fine.
Trying to delete p would be an error.

You cannot address p.
It doesn't exist.
Forget it, it's lost.
So is the memory allocated to initialize it.

So, don't do it this way.
Do what the article recommends: Use a container object.

Re: Challenging GotW 66's moral

George_George28-Dec-07 23:28

George_George

28-Dec-07 23:28

No Member 754960,

We can access in local function try block, but not in function try block -- they are two different things.

Here is the guideline from GotW

http://www.gotw.ca/gotw/066.htm[^]

--------------------
Moral #4: Always clean up unmanaged resource acquisition in local try-block handlers within the constructor or destructor body, never in constructor or destructor function-try-block handlers.
--------------------

If you have any issues, please feel free to let me know.

regards,
George

Re: Challenging GotW 66's moral

Member 75496029-Dec-07 4:47

Member 754960

29-Dec-07 4:47

The original question was in reference to the function try-catch handler.

If you want to use a local try catch block in the ctor body, as the GotW indicates, to handle the unmanaged memory, fine.

Re: Challenging GotW 66's moral

George_George29-Dec-07 19:52

George_George

29-Dec-07 19:52

Thanks Member 754960,

I agree. Cool.

regards,
George

Please let me ask again about creating unicode file.

xanagan66626-Dec-07 19:07

xanagan666

26-Dec-07 19:07

I try to convert my old MFC application that use multibye encoding to UNICODE by using TCHAR programming method.

but there is a code the create a file using ofstream that I dont know how to convert to TCHAR-programming.

I also tried std::wofstream

<br />
wofstream outFile(_T("outfile.txt"));<br />
outFile<<_T("Test international character : ???????,??????\n");<br />
outFile.close();<br />

But it didn't work , only the english portion is written to the output file (and the file are still ASCII as open in notepad).

Can someone suggest me how to fix the problem ?

Another question what is length in function like GetWindowText and GetCurrentDirectory are.Is it number of character or a number of byte ?

Edit : those ?????? are suppose to be thai and arabic text

Re: Please let me ask again about creating unicode file.

Maxwell Chen26-Dec-07 20:17

Maxwell Chen

26-Dec-07 20:17

Did you define _UNICODE in preprocessor definitions?

Maxwell Chen

Re: Please let me ask again about creating unicode file.

xanagan66626-Dec-07 22:59

xanagan666

26-Dec-07 22:59

yes the program are compiled and work as expect (I can input thai and arabic text in to database).

Only the file writing thing that didn't work.

Re: Please let me ask again about creating unicode file.

Maxwell Chen26-Dec-07 23:10

Maxwell Chen

26-Dec-07 23:10

You have to use binary mode to open the Unicode file.

Reference:
www.gamedev.net/community/forums/topic.asp?topic_id=362755

Maxwell Chen

Detailed view

john563226-Dec-07 19:07

john5632

26-Dec-07 19:07

Hi Experts,

How can I use detailed view in CListView?

Re: Detailed view

CPallini26-Dec-07 21:21

CPallini

26-Dec-07 21:21

What exactly do you need to know? Confused | :confused:

For instance, to set the list style you can see http://msdn2.microsoft.com/en-us/library/2hxsby1h(VS.80).aspx[^]
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.

[my articles]

Re: Detailed view

Nishad S26-Dec-07 22:59

Nishad S

26-Dec-07 22:59

You have to set the report view style, LVS_REPORT.

- NS -
[ODBaseBtn]

can anybody tell me why the size of the class is 16

philiptabraham26-Dec-07 18:59

philiptabraham

26-Dec-07 18:59

i have a class as mentioned below.The size of the class is only 16.Can anybody give me an explanation for this.Is this because of padding

class EXP
{
char c1;
char c2;
int i1;
int i2;
char *ptr;
static int mem;
};

THANKS IN ADVANCE

Re: can anybody tell me why the size of the class is 16

Maxwell Chen26-Dec-07 19:47

Maxwell Chen

26-Dec-07 19:47

There are "paddings" between some members of a structure. This is for convenience for the CPU to access. But you can change the padding size.

To view the positions and the sizes of paddings, you can list the addresses of each members as below.

EXP obj;
printf("obj.c1: 0x%p \nobj.c2: 0x%p \nobj.i1: 0x%p \n", &obj.c1, &obj.c2, &obj.i1);

Maxwell Chen

Re: can anybody tell me why the size of the class is 16

Haroon Sarwar26-Dec-07 21:44

Haroon Sarwar

26-Dec-07 21:44

http://en.wikipedia.org/wiki/Data_structure_alignment[^]

http://msdn2.microsoft.com/en-us/library/xh3e3fd0(VS.80).aspx[^]

Opening a file with name in UNICODE format

Ajay L D26-Dec-07 18:44

Ajay L D

26-Dec-07 18:44

Hi,
I am trying to open a file, whose name is in UNICODE string with a Byte-order Mark (BOM). How do I open such files? The CFile class fails to recognize such a name.

Thank you.
AJ

Re: Opening a file with name in UNICODE format [modified]

Maxwell Chen26-Dec-07 19:28

Maxwell Chen

26-Dec-07 19:28

#include <fstream>
wchar_t file_name[] = L"hello.txt"; // ... Your file name source.
// std::fstream f(file_name, std::ios::in | std::ios::out);
std::wfstream f(file_name, std::ios::in | std::ios::out);

Maxwell Chen

modified on Thursday, December 27, 2007 4:01:06 AM

Re: Opening a file with name in UNICODE format

Ajay L D26-Dec-07 21:31

Ajay L D

26-Dec-07 21:31

Thank you for your reply. But an existing file with Byte-order Mark (Ex: FFFE), will not open with the above code.

Re: Opening a file with name in UNICODE format [modified]

Maxwell Chen26-Dec-07 22:00

Maxwell Chen

26-Dec-07 22:00

Ajay L D wrote:
But an existing file with Byte-order Mark (Ex: FFFE), will not open with the above code.

I just made a file with the mark EF BB BF in the beginning three bytes of the content, and the content is in Chinese. I use the below code, and it can open and load data into fstream variable. (Sorry for my typo in last reply. Note the "w" of the type name.)

std::wifstream file(file_name, std::ios::in | std::ios::binary);

12-27 05:12 pm> The content loaded is incorrect... Sigh | :sigh:

12-27 06:10 pm> Oh you have to use binary mode to open Unicode files.
Reference:
www.gamedev.net/community/forums/topic.asp?topic_id=362755

Maxwell Chen

modified on Thursday, December 27, 2007 5:11:48 AM

Regarding taking video data from camera

adiveppanavar26-Dec-07 18:37

adiveppanavar

26-Dec-07 18:37

hello,
i am created client/server application,in server iam taking video file from the hard disk then sending to client.In client side i am reciving video data and writing into file(test.m4v) then doing decompressio,rendering using AVCODEC lib funtions.(in windows using vc++)

now i am trying without writing into file(test.m4v)directly can i take buffer then decompress it and render it.
tell me what i have to do.

thanks
AMK

Shell Context Menu

john563226-Dec-07 18:29

john5632

26-Dec-07 18:29

Hi Experts,

How can I create a shell context menu for files,folders,drives and recycle bin? what is the steps I have to follow?

Thanx in advance.

Re: Shell Context Menu

Naveen26-Dec-07 21:00

Naveen

26-Dec-07 21:00

Read this[^]

nave

[OpenedFileFinder]

Print Preview in FormView

Shivarudrayya H26-Dec-07 18:09

Shivarudrayya H

26-Dec-07 18:09

Hello Friends,
I developed a SDI application,in that i splitted the window.
ie:one view & 3 forms.
In one of the my form created a button as Preview.
Im calling printpreview from main window.using CView::OnFile......
But it hangs, can anybody tell mr how to do it.

thanks in advance.

Reagards
Shiva

Re: Print Preview in FormView

wira1guys26-Dec-07 20:29

wira1guys

26-Dec-07 20:29

When you create SDI/MDI with FormView using wizard, it will tell FormView can use printing support (Maybe that's the problem).
If I am not wrong, there is tutorial how to use print (form view) in code project.

Good Luck

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