Send/Recv

This is what I have:

Code:

---

/*
        Application:        Chat Client v1.0
        By:                                Brian Denys
        Email:                        [email protected]
*/

/*        Include Files        */
#include <winsock2.h>
#include <stdio.h>
#pragma comment(lib, "ws2_32")

#define BACKLOG 5

int __cdecl Send_to_Client(const char *ip, unsigned short Port, char *Message)
{
        /*        Declare and Initialize variables        */
        int iResult;
        WSADATA wsaData;
        SOCKET ConnectSocket;
        struct sockaddr_in clientConnect;

        /*        Initialize Winsock        */
        iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
        if(iResult != NO_ERROR)
        {
                printf("WSAStartup() failed.\n");
                return 1;
        }

        /*        Create socket to connect to server        */
        ConnectSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
        if(ConnectSocket == INVALID_SOCKET)
        {
                printf("Failed to create ConnectSocket.\n");
                WSACleanup();
                return 1;
        }

        /*        IP Address of client to send to        */
        clientConnect.sin_family = AF_INET;
        clientConnect.sin_addr.s_addr = inet_addr( ip );
        clientConnect.sin_port = htons ( Port );

        /*        Connect to client        */
        iResult = connect(ConnectSocket, (SOCKADDR*)&clientConnect, sizeof(clientConnect));
        if(iResult == SOCKET_ERROR)
        {
                printf("Failed to connect to client.\n");
                closesocket(ConnectSocket);
                WSACleanup();
                return 1;
        }

        /*        Send buffer        */
        iResult = send(ConnectSocket, Message, (int)strlen(Message), 0);
        if(iResult == SOCKET_ERROR)
        {
                printf("Failed to send buffer.\n");
                closesocket(ConnectSocket);
                WSACleanup();
                return 1;
        }else{
                printf("Bytes send: &#37;d.", iResult);
        }
       
        /*        Shutdown the connection        */
        iResult = shutdown(ConnectSocket, SD_SEND);
        if(iResult == SOCKET_ERROR)
        {
                printf("Shutdown connection failed.\n");
                closesocket(ConnectSocket);
                WSACleanup();
                return 1;
        }

        /*        Cleanup        */
        closesocket(ConnectSocket);
        WSACleanup();

}

int __cdecl Receive_from_Client(const char *ip, unsigned short Port)
{
        /*        Declare and initialize variables        */
        int iResult;
        WSADATA wsaData;
        SOCKET ConnectSocket;
        struct sockaddr_in clientRecv;
        int recvbuflen = 512;
        char recvbuf[512];

        /*        Initialize Winsock        */
        iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if (iResult != NO_ERROR) {
      printf("WSAStartup() failed.\n");
      return 1;
    }

        /*        Create a socket to connect to client        */
        ConnectSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (ConnectSocket == INVALID_SOCKET) {
        printf("socket() failed.\n");
        WSACleanup();
        return 1;
    }

        /*        IP Address and Port of the Client to connect to        */
        clientRecv.sin_family = AF_INET;
    clientRecv.sin_addr.s_addr = inet_addr( ip );
    clientRecv.sin_port = htons( Port );

        /*        Connect to client        */
        iResult = connect( ConnectSocket, (SOCKADDR*) &clientRecv, sizeof(clientRecv) );
    if ( iResult == SOCKET_ERROR) {
        closesocket (ConnectSocket);
        printf("Connect to client failed.\n");
        WSACleanup();
        return 1;
    }

        /*        Receive from Client        */
        iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
        printf("Received: %d\n", iResult);

        /*        Shutdown the connection        */
        iResult = shutdown(ConnectSocket, SD_SEND);
        if(iResult == SOCKET_ERROR)
        {
                printf("Shutdown connection failed.\n");
                closesocket(ConnectSocket);
                WSACleanup();
                return 1;
        }

        /*        Cleanup        */
        closesocket(ConnectSocket);
        WSACleanup();

}

int Listen_for_Client(unsigned short Port)
{
        /*        Declare and initialize variables        */
        int iResult;
        WSADATA wsaData;
        SOCKET ConnectSocket;
        struct sockaddr_in clientListen;

        /*        Initialize Winsock        */
        iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if (iResult != NO_ERROR) {
      printf("WSAStartup() failed.\n");
      return 1;
    }

        /*        Create a socket to connect to client        */
        ConnectSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (ConnectSocket == INVALID_SOCKET) {
        printf("socket() failed.\n");
        WSACleanup();
        return 1;
    }

        /*        IP Address and Port of the Client to connect to        */
        clientListen.sin_family = AF_INET;
    clientListen.sin_addr.s_addr = htonl(INADDR_ANY);
    clientListen.sin_port = htons( Port );

        /*        Bind        */
        iResult = bind(ConnectSocket, (SOCKADDR*)&clientListen, sizeof(clientListen));
        if(iResult == SOCKET_ERROR)
        {
                printf("bind() failed.\n");
                closesocket(ConnectSocket);
                WSACleanup();
                return 1;
        }

        /*        Listen        */
        iResult = listen(ConnectSocket, BACKLOG);
        if(iResult == SOCKET_ERROR)
        {
                printf("listen() failed.\n");
                closesocket(ConnectSocket);
                WSACleanup();
                return 1;
        }

        printf("Listening on socket ..\n");

        /*        Cleanup        */
        WSACleanup();

}

void Create1()
{
                Send_to_Client("127.0.0.1", 1111, "Test.");
}

void Create2()
{
        Receive_from_Client("127.0.0.1", 1111);
}

void Create3()
{
        Listen_for_Client(1111);
}

int __cdecl main()
{
        CreateThread(NULL, 0, (unsigned long(__stdcall*)(void*))Create3, NULL, 0, NULL);
        CreateThread(NULL, 0, (unsigned long(__stdcall*)(void*))Create2, NULL, 0, NULL);
        CreateThread(NULL, 0, (unsigned long(__stdcall*)(void*))Create1, NULL, 0, NULL);

        system("pause");
        return 0;
}

---

I don't receive the msg i just send, why?

Code:

---

/*
        Application:        Chat Client v1.0
        By:                                Brian Denys
        Email:                        [email protected]
*/

/*        Include Files        */
#include <winsock2.h>
#include <stdio.h>
#pragma comment(lib, "ws2_32")

#define BACKLOG 5

int __cdecl Send_to_Client(const char *ip, unsigned short Port, char *Message)
{
        /*        Declare and Initialize variables        */
        int iResult;
        WSADATA wsaData;
        SOCKET ConnectSocket;
        struct sockaddr_in clientConnect;

        /*        Initialize Winsock        */
        iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
        if(iResult != NO_ERROR)
        {
                printf("WSAStartup() failed.\n");
                return 1;
        }

        /*        Create socket to connect to server        */
        ConnectSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
        if(ConnectSocket == INVALID_SOCKET)
        {
                printf("Failed to create ConnectSocket.\n");
                WSACleanup();
                return 1;
        }

        /*        IP Address of client to send to        */
        clientConnect.sin_family = AF_INET;
        clientConnect.sin_addr.s_addr = inet_addr( ip );
        clientConnect.sin_port = htons ( Port );

        /*        Connect to client        */
        iResult = connect(ConnectSocket, (SOCKADDR*)&clientConnect, sizeof(clientConnect));
        if(iResult == SOCKET_ERROR)
        {
                printf("Failed to connect to client.\n");
                closesocket(ConnectSocket);
                WSACleanup();
                return 1;
        }

        /*        Send buffer        */
        iResult = send(ConnectSocket, Message, (int)strlen(Message), 0);
        if(iResult == SOCKET_ERROR)
        {
                printf("Failed to send buffer.\n");
                closesocket(ConnectSocket);
                WSACleanup();
                return 1;
        }else{
                printf("Message send: %s.", Message);
        }
       
        /*        Shutdown the connection        */
        iResult = shutdown(ConnectSocket, SD_SEND);
        if(iResult == SOCKET_ERROR)
        {
                printf("Shutdown connection failed.\n");
                closesocket(ConnectSocket);
                WSACleanup();
                return 1;
        }

        /*        Cleanup        */
        closesocket(ConnectSocket);
        WSACleanup();

}

int Listen_for_Client(unsigned short Port)
{
        /*        Declare and initialize variables        */
        int iResult2;
        WSADATA wsaData2;
        SOCKET ConnectSocket2;
        SOCKET AcceptSocket;
        struct sockaddr_in clientListen;
        int recvbuflen = 512;
        char recvbuf[512];

        /*        Initialize Winsock        */
        iResult2 = WSAStartup(MAKEWORD(2,2), &wsaData2);
    if (iResult2 != NO_ERROR) {
      printf("WSAStartup() failed.\n");
      return 1;
    }

        /*        Create a socket to connect to client        */
        ConnectSocket2 = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (ConnectSocket2 == INVALID_SOCKET) {
        printf("socket() failed.\n");
        WSACleanup();
        return 1;
    }

        /*        IP Address and Port of the Client to connect to        */
        clientListen.sin_family = AF_INET;
    clientListen.sin_addr.s_addr = htonl(INADDR_ANY);
    clientListen.sin_port = htons( Port );

        /*        Bind        */
        iResult2 = bind(ConnectSocket2, (SOCKADDR*)&clientListen, sizeof(clientListen));
        if(iResult2 == SOCKET_ERROR)
        {
                printf("bind() failed.\n");
                closesocket(ConnectSocket2);
                WSACleanup();
                return 1;
        }

        /*        Listen        */
        iResult2 = listen(ConnectSocket2, BACKLOG);
        if(iResult2 == SOCKET_ERROR)
        {
                printf("listen() failed.\n");
                closesocket(ConnectSocket2);
                WSACleanup();
                return 1;
        }

        printf("Listening on socket ..\n");

        /*        Accept        */
        while(true){
        AcceptSocket = accept(ConnectSocket2, NULL, NULL);
        if (AcceptSocket == INVALID_SOCKET)
        {
                printf("accept() failed\n");
                closesocket(ConnectSocket2);
                WSACleanup();
                return 1;
        }else{
                printf("Client connected.\n");
                iResult2 = recv(AcceptSocket, recvbuf, recvbuflen, 0);
        printf("Message received: %s\n", &recvbuf);
        }
        }

        /*        Cleanup        */
        closesocket(ConnectSocket2);
        WSACleanup();

}

void Create2()
{
        char *Msg = "omg";
                Send_to_Client("127.0.0.1", 1111, Msg);
}

void Create1()
{
        Listen_for_Client(1111);
}

int __cdecl main()
{
        CreateThread(NULL, 0, (unsigned long(__stdcall*)(void*))Create1, NULL, 0, NULL);
        CreateThread(NULL, 0, (unsigned long(__stdcall*)(void*))Create2, NULL, 0, NULL);

        system("pause");
        return 0;
}

---

Why I am getting a buch of strange characters in my receive?

you do not send the null termination.
So obviously - you do not receive it

Or - while printing add preceision to your format to print exactly the same number of chars you have received

Or add the null terminator manually - after the last received character before printing (check for memory overrun in this solution)

Thanks got that working =]
Now i still have to make a chat client from that =]

If you want to process several connections - maybe better to start work asynchrony on the select

Whats wrong with:

Code:

---

char *Msg;
cin >> Msg;
printf(Msg);

---

I'm using VC2008

Do you mean aside from you not allocating any memory for Msg?

--
Mats

Quote:

---

Originally Posted by matsp

Do you mean aside from you not allocating any memory for Msg?

--
Mats

---

Unhandled exception at 0x104e63b1 in Chat.exe: 0xC0000005: Access violation writing location 0xcccccccc.

Quote:

---

Originally Posted by brietje698

Unhandled exception at 0x104e63b1 in Chat.exe: 0xC0000005: Access violation writing location 0xcccccccc.

---

Yes, let me guess that "Msg" happens to be 0xcccccccc when you do this? Have you tried actually single-stepping into the function, rather than asking here? Do you understand how cin and printf() uses memory?

You have not set Msg to a valid memory location to write to, and since Visual Studio ensures that uninitialized variables are still set to a defined value, you get this, rather than just randomly overwriting something in your memory - much better, I think.

--
Mats

Quote:

---

Originally Posted by brietje698

Whats wrong with:

Code:

---

char *Msg;
cin >> Msg;
printf(Msg);

---

---

The first parameter of printf treats % as special, so you'd have to do it like this:

Code:

---

char *Msg;
cin >> Msg;
printf("%s",Msg);

---

Quote:

---

Originally Posted by robwhit

The first parameter of printf treats % as special, so you'd have to do it like this:

Code:

---

char *Msg;
cin >> Msg;
printf("%s",Msg);

---

---

it the line

Code:

---

cin >> Msg;

---

thats givng me the error

That's because Msg points to one byte (assuming char is 1 byte) of memory. You are assuming it is pointing to a chunk of memory big enough to hold whatever is inputted. The program may or may not crash depending on who or what owns the memory directly after the 1 byte pointed to by Msg. If you want to make sure that you have a chunk of memory you need to ALLOCATE it.

in C:

Code:

---

Msg = malloc(sizeof(char) * HoweverManyCharactersYouExpect);

---

in C++

Code:

---

Msg = new char[HoweverManyCharacterYouExpect];

---

Msg isn't allocalted any memory. Make it an array or dynamically allocate it.

You can't allocate memory and you are writing a socket program?? Hmmm.