Re: Initialize empty buffer - C / C++ / MFC Discussion Boards

Re: Initialize empty buffer

chandu00412-Oct-07 0:59

chandu004

12-Oct-07 0:59

try strlen (tempBufferWrite) inside your write function.

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chandu.

Re: Initialize empty buffer

CodingLover12-Oct-07 1:07

CodingLover

12-Oct-07 1:07

You mean set the buffer size to length of the string(text)?

Eranga Smile | :)

I appreciate your help all the time...

Re: Initialize empty buffer

Nelek12-Oct-07 1:10

Nelek

12-Oct-07 1:10

mmm,

you are writing "text of letters" (16 chars including '\0'), but you have actually 256 bytes in the buffer and is not a pointer so the size is fix to you init value. That means the rest is going to be written with waste values.

Try:

void CSRFToolDlg::OnBnClickedWrite()
{
char* tempBufferWrite = NULL;

tempBufferWrite = new char[256];

tempBufferWrite = "text of letters";  //or something longer, it should be the same

openFile.Write(tempBufferWrite , sizeof(tempBufferWrite)) ;
openFile.Flush() ;
}

Greetings.

--------
M.D.V.

If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?

Help me to understand what I'm saying, and I'll explain it better to you

Wink | ;)

Re: Initialize empty buffer

CodingLover12-Oct-07 1:19

CodingLover

12-Oct-07 1:19

Seems it works. Thanks.

Now I'm going to slightly change it with dynamic text, like text from control box. I come back here if I got any issue there.

Eranga Smile | :)

I appreciate your help all the time...

Re: Initialize empty buffer

Nishad S12-Oct-07 1:20

Nishad S

12-Oct-07 1:20

Nelek wrote:
tempBufferWrite = new char[256];tempBufferWrite = "text of letters"; //or something longer, it should be the same

This is for what?

- NS -

Re: Initialize empty buffer

Nelek12-Oct-07 2:02

Nelek

12-Oct-07 2:02

mmm, I just made some changes but leaving his point of view.

Anyways, if it is not correct, or it is useless... instead of just ask "this is for what?" would be better to say, "this is not right, you should use...", so I would learn as the same time I try to help Smile | :)

Re: Initialize empty buffer

chandu00412-Oct-07 1:38

chandu004

12-Oct-07 1:38

Eranga Thennakoon wrote:
void CSRFToolDlg::OnBnClickedWrite()
{
char tempBufferWrite[256] = {0} ; // or {}
openFile.Write("text of letters", sizeof(tempBufferWrite)) ;
openFile.Flush() ;
}

instead of

sizeof(tempBufferWrite)

there you put strlen(tempBufferWrite)

thats it.

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prefix your main thread subject with [SOLVED] if it is solved.
chandu.

Re: Initialize empty buffer

David Crow12-Oct-07 2:54

David Crow

12-Oct-07 2:54

chandu004 wrote:
there you put strlen(tempBufferWrite)

That would equate to 0, which is obviously wrong. The second argument to Write() should be the number of bytes in the first argument.

"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

Re: Initialize empty buffer

chandu00412-Oct-07 3:10

chandu004

12-Oct-07 3:10

the length of hte string should obviously be the number of bytes in that string right??!

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chandu.

Re: Initialize empty buffer

David Crow12-Oct-07 3:40

David Crow

12-Oct-07 3:40

How you choose to say it is up to you, but the second argument to Write() must be the number of bytes in the first argument.

"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

Re: Initialize empty buffer

chandu00412-Oct-07 5:44

chandu004

12-Oct-07 5:44

please tell me what is the first argument, here and what is its size.
iam very sure that you may be right, but please let me know what is that wrong i have done.
thank you.

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chandu.

Re: Initialize empty buffer

David Crow12-Oct-07 5:49

David Crow

12-Oct-07 5:49

chandu004 wrote:
please tell me what is the first argument...

In your example here, the first argument is the string literal "text of letters".

"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

Re: Initialize empty buffer

chandu00412-Oct-07 6:21

chandu004

12-Oct-07 6:21

yah yah
i got it by seeing the nelek's post.
thank you very much(for both of you) for correcting me.

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chandu.

Re: Initialize empty buffer

Nelek12-Oct-07 4:01

Nelek

12-Oct-07 4:01

In this case won't work, because the tempBufferWrite is 256 chars long, but the string that is being written in the file is "text of letters" (16 chars), and note that there is no string to have length of. The code gives the "..." directly, not going through the buffer.

char tempBufferWrite[256] = "Test of letters" ; // or {}
openFile.Write(&tempBufferWrite, strlen(tempBufferWrite)) ;

That should work. What you proposed just changing sizeof with strlength must not.

Re: Initialize empty buffer

chandu00412-Oct-07 5:54

chandu004

12-Oct-07 5:54

thanks for the analysis,

Nelek wrote:
char tempBufferWrite[256] = "Test of letters" ; // or {}openFile.Write(&tempBufferWrite, strlen(tempBufferWrite)) ;

That should work

i was thinking that, &tempBufferWrite is used in the write,
i didnt observe some other readstring in that place.

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prefix your main thread subject with [SOLVED] if it is solved.
chandu.

Re: Initialize empty buffer

CodingLover14-Oct-07 17:52

CodingLover

14-Oct-07 17:52

Thanks,

Than mean strlen get the length of CString.

Eranga Smile | :)

I appreciate your help all the time...

Re: Initialize empty buffer

toxcct12-Oct-07 2:06

toxcct

12-Oct-07 2:06

anyway, just a guess: i see you're coding in C++, so why not using std::string or even CString (if using MFC) ... ?

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Re: Initialize empty buffer

CodingLover14-Oct-07 17:57

CodingLover

14-Oct-07 17:57

Actually that readString defines as CString in my code.

Eranga Smile | :)

I appreciate your help all the time...

Re: Initialize empty buffer

Mike Dimmick12-Oct-07 6:13

Mike Dimmick

12-Oct-07 6:13

openFile.Write(tempBuffer, amount of data you wrote to tempBuffer);

Don't pass the whole buffer length when you didn't fill that much.

DoEvents: Generating unexpected recursion since 1991

Re: Initialize empty buffer

CodingLover14-Oct-07 18:01

CodingLover

14-Oct-07 18:01

Actually that what I've worried about. Couldn't find any way to define the buffer length as the length of string. Actually I tried something like this.

readString.GetLength()

Eranga Smile | :)

I appreciate your help all the time...

Help with MSDN

gReaen11-Oct-07 23:40

gReaen

11-Oct-07 23:40

how can i install msdn library in vc++ 6.0 ??? I'm getting a message as "Please reinstall msdn" when i click on help.....

Re: Help with MSDN

CodingLover12-Oct-07 0:48

CodingLover

12-Oct-07 0:48

Can you run MSDN individually. At the installation you have a option to combine both MSDN and Visual C++ together. If you neglect that option you have to work with them separately.

Eranga Smile | :)

I appreciate your help all the time...

Re: Help with MSDN

Nishad S12-Oct-07 1:16

Nishad S

12-Oct-07 1:16

You might be using newer version of MSDN, which cant be taken directly from VC6.

- NS -

Re: Help with MSDN

David Crow12-Oct-07 2:57

David Crow

12-Oct-07 2:57

What version of MSDN are you working with?

"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

Re: Help with MSDN

Mike Dimmick12-Oct-07 6:24

Mike Dimmick

12-Oct-07 6:24

The newest version of MSDN Library that still integrates with Visual Studio 6.0 is October 2001. It may still be possible to download this if you're an MSDN subscriber (although not right now as the subscriber download site doesn't seem to be working).

A very out-of-date version of MSDN Library accompanied Visual Studio 6.0 itself (labelled 'MSDN Library for Visual Studio 6.0'). However, this predates Windows 2000 and I would not recommend using it. (It was up-to-date in mid-1998 when Visual Studio 6.0 was released!)

DoEvents: Generating unexpected recursion since 1991

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