C / C++ / MFC

Re: Determining Data Size For Network Send/Rec :: Winsock

7-May-02 4:49

Hi.

Okay. Basically, the program will be a client and a server. If it is connected to any other client/server, than the connect feature will be disabled.

As for the message, I plan to send and receive message and and forth. As for I/O mode and I/O model, I will use the simple WSAAsynSelect (non-blocking) model since it uses the Windows (MFC) messaging system.

Kuphryn

valikac7-May-02 4:45

Re: Determining Data Size For Network Send/Rec :: Winsock

7-May-02 4:45

Thanks.

Kuphryn

Niklas L6-May-02 22:10

Niklas L

6-May-02 22:10

From heart:

char szMsg[] = "A message";
long nMsgSize = strlen(szMsg);
long nSize = nMsgSize;
nSize = htonl(nSize); // Convert to net byte order
send(sock, &nSize, sizeof(long), 0);
send(sock, szMsg, nMsgSize, 0);

This example uses a four byte length header.
Now, when reading

long nSize;
recv(sock, &nSize, sizeof(long), 0);
nSize = ntohl(nSize); // Convert to host byte order
char *pszMsg = new char[nSize + 1];
recv(sock, pszMsg, nSize, 0);
pszMsg[nSize] = '\0';

pszMsg will now, hopefully Smile | :)

, contain your message.

Re: Determining Data Size For Network Send/Rec :: Winsock

valikac7-May-02 4:39

Re: Determining Data Size For Network Send/Rec :: Winsock

7-May-02 4:39

Wow. Nice!

Thanks.

Okay. I want to walk through your code one part at a time.

1)According to the above, you did not use "4" as byte count anywhere in the code. You used a long variable as the static size of the first four bytes. Is that correct? If yes, what is the advantage to using sizeof(long) stead of just this:

// char fourbyte[4];
//send(sock, fourbyte, 4, 0);

2) You used the function htonl() to convert to "net byte order." Jones and Ohlund dedicated a section or so to four functions that converts between byte order (host byte order to/from network byte order). Can you explain why we eed htonl()?

Dire.Wolf posted another technique using WSARevc(). Here is a link to the code.

http://www.gamedev.net/community/forums/topic.asp?topic_id=93771

I will try both your technique and the one Dire.Wolf mentioned. Although, your technique is more flexible in the sense that we do not need to know the size of the data after the first four byte. The size of the data after the first four byte will be calculated and then a character array is created at that size. Very nice!

Thanks again,
Kuphry

7-May-02 19:55

Note from MSDN
int recv(
SOCKET s,
char FAR *buf,
int len, //sizeof buffer NOT amount to read
int flags
);

"For connection-oriented sockets (type SOCK_STREAM for example), calling recv will return as much information as is currently available—up to the size of the buffer supplied"

Correct me here if I am wrong but;

So if ALL the info is not available at the time of the call it will return with less. The next time you call recv() you will be expecting a size amount but the remainder of the previous string will be there. Splat!

while(iRecv < iLen)
iRecv+= recv(socket ,&sBuffer[iRecv] ,iLen, FLAGS); //this could work

Now what happens if the amount in the socket is greater than the buffer size (ie Next string is there as well)?
recv() returns an error, WSAEMSGSIZE and waits until a buffer large enough is supplied. But you can't get a buffer large enough as you need to read from the socket to get the size of the second msg.

Enable/Disable A Window in SplitView :: MFC

valikac6-May-02 18:32

6-May-02 18:32

Hi.

I would like to know how to enable/disable a specific view inside a split window. For example, let there the split window comes default with three visible windows.

-----
View1
-----
View2
-----
View3
-----

If the user select an option in the menu to hide view2 or maybe a calculated needs to disable view2, is there a way to do that in MFC?

Most important that is the entire window must be redrawn. I am not sure how to redraw multiviews inside of main in SDI architecture.

Thanks,
Kuphryn

CString!

tongc6-May-02 17:21

tongc

6-May-02 17:21

Hi Could anyone kindly show me how to remove the last character in CString pls
I've tried Delete and Remove but it didnt' work

Thanks

Bugra Barin6-May-02 17:32

Bugra Barin

6-May-02 17:32

Delete should work

CString cs = "String";
cs.Delete(cs.GetLength()-1);

tongc6-May-02 23:24

tongc

6-May-02 23:24

Hi Your solution just doesn't work. But thanks anyway.

Cheers

Nish Nishant6-May-02 17:37

6-May-02 17:37

tcuong wrote:
Could anyone kindly show me how to remove the last character in CString pls

m_string=m_string.Left(m_string.GetLength()-1);

Nish

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tongc6-May-02 23:24

tongc

6-May-02 23:24

Hi
This work perfectly

Thanks for assistant

a newbie question

dhon6-May-02 17:13

dhon

6-May-02 17:13

how can i make my .cpp file member of my project?

Re: a newbie question

Nish Nishant6-May-02 17:19

6-May-02 17:19

dhon wrote:
how can i make my .cpp file member of my project?

From the "Project" menu, take "Add to Project" and then "New"

Nish

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Borderless Splitter

alpha+6-May-02 16:59

alpha+

6-May-02 16:59

what does it take to make a borderless splitter window in VC6? I want to put a few views one next to each other, without the "border" between them.

is there any "simple" way to do it (meaning, one call does the work) or should I derive a class from CSplitterWnd, change a few internal member variables (sizes & colors), and force them to draw a splitter which blends with the background?

thanks.

Re: Borderless Splitter

Shog⁹6-May-02 17:04

Shog⁹

6-May-02 17:04

Views are just windows, so you can arrange them in what ever way pleases you. If it works best for you to use CSplitterWnd, then do so; it is not too difficult to create a derived class that will draw the splitters in any way you choose. Do a search here for splitter; I think you'll have several articles to choose from.

--------
I don't think that I'm a sell-out but I do "Enjoy Coke!"...

-- Bloodhound Gang, The Inevitable Return Of The Great White Dope

screen mate

6-May-02 16:47

How I know what my screen mate move pass each window component (such as edge of window..etc.) ?

Thank a lot

Shog⁹6-May-02 17:06

Shog⁹

6-May-02 17:06

What is a screen mate? Confused | :confused:

(and if you reply "that square thing in front of you mate", i will hurt you Wink | ;)

)

--------
I don't think that I'm a sell-out but I do "Enjoy Coke!"...

-- Bloodhound Gang, The Inevitable Return Of The Great White Dope

Nish Nishant6-May-02 17:21

6-May-02 17:21

Shog⁹ wrote:
and if you reply "that square thing in front of you mate", i will hurt you

LOL
Seriously I think he means some kinda funny desktop program that does fun stuff, like walk into the screen randomly and strip or something.

Nish

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Nish Nishant6-May-02 17:19

6-May-02 17:19

Screen mate?
Is that some kinda fancy desktop application?

Nish

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6-May-02 20:43

yes. sometime called "desktop toy"

the screen mate will move on desktop and do something fun
I want to know what's component that screen mate move over (such as edge of window app)

Thank a lot

Re: POST MESSAGE help needed

Maxwell Chen6-May-02 21:09

Maxwell Chen

6-May-02 21:09

The personnel manageress in my company has a very cute penguin screen mate!

Maxwell Chen
People say "No news is good news". Then, no code is good code!?

POST MESSAGE help needed

6-May-02 15:17

I have written a button class that sends a user defined message when clicked. The message is passed as a parameter when the button is created.

It works if I know the specific window to post the message to. How do I post the message so a class that is not known untill runtime can handle it?

Would it make more sense to store a CWnd* as member data for the window to send the message to?

Thanks, ~Paul~

Nish Nishant6-May-02 15:29