C / C++ / MFC

2-Aug-05 23:16

I don't understand what you mean Confused | :confused:

... she said you are the perfect stranger she said baby let's keep it like this... Tunnel of Love, Dire Straits.

TCP Programming

Member 21610042-Aug-05 20:11

2-Aug-05 20:11

I now doing a project that I don't know how to start. I need to know how the
TCP work and write a program to send data from a PC to another PC using visual c++. After knowing how the TCP work, I need to write a program to send and receive message from Host PC to PLC follow the MODBUS format. Can help me.... Confused | :confused:

toxcct2-Aug-05 20:36

2-Aug-05 20:36

you should have a look at the MSDN, especially on CSocket[^] and CAsynSocket[^] classes...

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Member 21610042-Aug-05 22:28

2-Aug-05 22:28

I just go through the CAsyncSocket and I start program a little but got some error that I don't understand,can help me.....
Below is my code:
#include "iostream.h"
#include "afxsock.h"

BOOL Create(
UINT nSocketPort = 0,
int nSocketType = SOCK_STREAM,
long lEvent = FD_READ | FD_WRITE | FD_OOB | FD_ACCEPT | FD_CONNECT | FD_CLOSE,
LPCTSTR lpszSocketAddress = NULL
);

when I compile, it show the error below:
libcd.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/TEST.exe : fatal error LNK1120: 1 unresolved externals
D'Oh! | :doh:

toxcct2-Aug-05 22:33

2-Aug-05 22:33

looking at the linker error, your program don't have any main() function...

where did you put the code so ?

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Member 21610042-Aug-05 23:02

2-Aug-05 23:02

I very weak in programming and never learn visual c++ before...
What you mean by main() function. So, I cannot start a program without main() functon?

toxcct3-Aug-05 0:55

3-Aug-05 0:55

Tsaejen wrote:
What you mean by main() function. So, I cannot start a program without main() functon?

exactly, that's it....

actually, when a C/C++ program starts, the runtime looks for the main() function...

so, the program must be put into main() (at least, the beginning)...

TOXCCT >>> GEII power
[toxcct][VisualCalc]

markkuk3-Aug-05 2:40

markkuk

3-Aug-05 2:40

You must learn the basics of C++ before you can start working on TCP/IP in C++. If you even don't know what main() is, you can forget TCP and sockets for a long time.

Member 21610042-Aug-05 23:57

2-Aug-05 23:57

#include "iostream.h"
#include "afxsock.h"
#include "stdlib.h"

main()

{
return 0;
};

////////////////////////////////////////////////////////////////////////////////////////
// Create a socket

BOOL Create(
UINT nSocketPort = 0,
int nSocketType = SOCK_STREAM,
long lEvent = FD_READ | FD_WRITE | FD_OOB | FD_ACCEPT | FD_CONNECT | FD_CLOSE,
LPCTSTR lpszSocketAddress = NULL
);

////////////////////////////////////////////////////////////////////////////////////////
// Client socket Connect function

BOOL Connect(
LPCTSTR lpszHostAddress,
UINT nHostPort
);
BOOL Connect(
const SOCKADDR* lpSockAddr,
int nSockAddrLen
);

////////////////////////////////////////////////////////////////////////////////////////
// Server socket listen function

BOOL Listen(
int nConnectionBacklog = 5
);

////////////////////////////////////////////////////////////////////////////////////////
// Server socket Accept function

virtual BOOL Accept(
CAsyncSocket& rConnectedSocket,
SOCKADDR* lpSockAddr = NULL,
int* lpSockAddrLen = NULL
);

My code is above but still have error, help.....
error C2575: 'Accept' : only member functions and bases can be virtual

toxcct3-Aug-05 1:07

3-Aug-05 1:07

i think you should first learn for C/C++.

secondly, what are you trying to do with that code ?

your code above is not correct :

#include "iostream.h"
#include "afxsock.h"
#include "stdlib.h"

main()
{
return 0;
};

1) you declare main() without any returning type.
2) the ending ; is not correct there
3) the header files are standard headers, so they shouldn't be between "" but <> instead. Moreover, afx includes should be the first files to be includes
4) the program enters main, then execute the first instruction it finds (here return 0), which tells it to exit the function (so, also exiting the program, as main can be seen as the program at your level).

revise it this way :

#include <afxsock.h>
#include <iostream.h>
#include <stdlib.h>
 
void main(void) {
    //write what the program is supposed to do here
    //....
}

ok, then, what do you want to do with the following functions ?
it seems that you just copied/pasted some code you found in the doc into your source...
DON'T !!
these functions are already coded (and i doubt you could rewrite them by yourself seeing your advanced knowledge on the language).
just use them as the MSDN tells you to (right number of parameter, and matching types). also be careful of the case (C/C++ are case sensitive).
well now, give me a better piece of code in consequence and i'll try to help you more.

see you,

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Marc Soleda2-Aug-05 20:54

2-Aug-05 20:54

In CP there are quite a lot of projects related to sockets.
Network Transfer Of Files Using MFC's CSocket Class[^]

Marc Soleda.

... she said you are the perfect stranger she said baby let's keep it like this... Tunnel of Love, Dire Straits.

Member 21610042-Aug-05 22:57

2-Aug-05 22:57

I was given a sch project and I have a deadline to complete the project. But now I stil don't know how to start the programming part. I also very weak in programming and never study visual c++ before. Very STRESS!!!!

The project is about MODBUSTCP PROTOCOL. I need to create a Dialog that can send data to PLC. I already created a Dialog that contains edit box to enter Destination IP Address, 2 radio button to choose MODBUS or MEWTOCOL, edit box to type message and send the message, and also a group box include some button which label door open that when I click on the button, it will send a message tell the PLC to open the dooor.

And now I don't know how to write the program that when I type a message and send to another Destination(IP Address). Cry | :((

Marc Soleda2-Aug-05 23:07

2-Aug-05 23:07

I think you are in trouble Unsure | :~

If anybody in this forum could help you'd have to be more concrete and send the different pieces of code that didn't work.

Do you use a wrapper class or you have to build at your own?

Marc Soleda.

... she said you are the perfect stranger she said baby let's keep it like this... Tunnel of Love, Dire Straits.

Member 21610042-Aug-05 23:34

2-Aug-05 23:34

What is wrapper class?

My lecturer want me to use console application to try to do my testing on sending message first, and tell me to understand how TCP work then I will know how to do the MODBUS part....but I still not very understand the TCP work......

Marc Soleda2-Aug-05 23:56

2-Aug-05 23:56

Tsaejen wrote:
What is wrapper class?

It provides an easy/summarized way (sometimes extends) to use a class and some of its methods.

Tsaejen wrote:
....but I still not very understand the TCP work......

Read CAsyncSockets[^]
and take a look to Client[^] and server[^] samples.

Marc Soleda.

... she said you are the perfect stranger she said baby let's keep it like this... Tunnel of Love, Dire Straits.

toxcct3-Aug-05 1:59

3-Aug-05 1:59

RFC 793 : TCP[^]

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Member 21610043-Aug-05 16:02

Please help me with my Thread Problem

3-Aug-05 16:02

I actually want to start my program to do the socket programming. So the program I send to you yesterday, izit right to start like that?

Unicode support

bshti2-Aug-05 19:45

bshti

2-Aug-05 19:45

Help me, please to change my MFC applications to unicode supported application.
I've already found a lot of articles about it, I've defined _UNICODE symbol and set wWinMainCRTStartup entry point. But I'm still cannot pass link - I get an error "unresolved external symbol WinMain". My quastions are:
1) Do I have to define all this for all DLL-s or only for main project?
2) Which library I have to use - mfc42 or mfc42u etc
3) What else I have to do to link my application?

Thanks,
Bella

chiyinhk2-Aug-05 18:22

chiyinhk

2-Aug-05 18:22

Hi everyone, I am new to C++ Thread Programming, but I ran into a situation where my thread function never gets called, below is my code:

#include "StdAfx.h"
#include
#include

using namespace std;

static DWORD WINAPI kill (LPVOID p)
{
cout<<"Threading now";

return 0;
};

void main()
{

HANDLE t = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)kill, NULL, 0, NULL);

}

Can anyone tell me why the function "kill" never gets called? This is compiled in Visual C++ 6.0 under Windows 2000 Professtional. And how can I fix this?

Thanks

Andy Brummer2-Aug-05 18:38

Andy Brummer

2-Aug-05 18:38

Now that you are in the right forum, the simple answer is to add a Sleep(1000); right after your call to CreateThread. That will allow you to see the output.

Next, look up the CreateEvent API and replace your Sleep call to a WaitForSingleObject call on the event that gets triggered by the thread function to let you know that it is complete.

This is an excellent book for understanding basic multithreading techniques.

Multithreaded Programming with Win32[^]

I can imagine the sinking feeling one would have after ordering my book,
only to find a laughably ridiculous theory with demented logic once the book arrives - Mark McCutcheon

peterchen2-Aug-05 20:03

peterchen

2-Aug-05 20:03

You don't need an event, you can wait on the thread handle

Pandoras Gift #44: Hope. The one that keeps you on suffering.
aber.. "Wie gesagt, der Scheiss is' Therapie"
boost your code || Fold With Us! || sighist | doxygen

Andy Brummer2-Aug-05 20:15

Andy Brummer

2-Aug-05 20:15

That's true. I always forget about that D'Oh! | :doh:

, since I've mostly worked with threads on servers and you usually only let threads close down when the entire process is shutting down and you stop handling requests.

I can imagine the sinking feeling one would have after ordering my book,
only to find a laughably ridiculous theory with demented logic once the book arrives - Mark McCutcheon