Connect a socket of TCP/IP on the same machine, R2009b and VC++2008 express SP1

Hello

I tried to connect a TCP/IP socket. Before connect remote machines, I want to test the communication on the same machine.

I tested the socket program with C++ already. And It works properly.

However, when I test same routines on the C-mex file, it downs Matlab.

I wrote down the socket program as like bellows.

----------------------------------------------------------------

--- Server side ---

// Global variables for TCP/IP

int srcSocket; // this program

int dstSocket; // remote program

// sockaddr_in structure

struct sockaddr_in srcAddr;

struct sockaddr_in dstAddr;

int dstAddrSize = sizeof(dstAddr);

int status;

int numrcv;

char buffer[1024];

WSADATA data;

#define MDL_START /* Change to #undef to remove function */

#if defined(MDL_START)

static void mdlStart(SimStruct *S) {

   // Initialize socket

   WSAStartup(MAKEWORD(2,0), &data);

   memset(&srcAddr, 0, sizeof(srcAddr));
   srcAddr.sin_port = htons(PORT);
   srcAddr.sin_family = AF_INET;
   srcAddr.sin_addr.s_addr = htonl(INADDR_ANY); // allow any address to receive data

   // open socket, stream type
   srcSocket = socket(AF_INET, SOCK_STREAM, 0);

   // bind sockek
   bind(srcSocket, (struct sockaddr *) &srcAddr, sizeof(srcAddr));

   // allow connection
   listen(srcSocket, 1); 

   // accept connection
   dstSocket = accept(srcSocket, (struct sockaddr *) &dstAddr, &dstAddrSize);

} #endif /* MDL_START */

--- Client side ---

// Global variables for TCP/IP

char destination[] = "192.168.11.8";

int dstSocket;

struct sockaddr_in dstAddr;

char buffer[1024];

WSADATA data;

#define MDL_START /* Change to #undef to remove function */

#if defined(MDL_START)

static void mdlStart(SimStruct *S) {

   WSAStartup(MAKEWORD(2,0), &data);

   // Set the structure of sockaddr_in
   memset( &dstAddr, 0, sizeof(dstAddr));
   dstAddr.sin_port = htons(PORT);
   dstAddr.sin_family = AF_INET;
   dstAddr.sin_addr.s_addr = inet_addr(destination);

   // Create a socket
   dstSocket = socket( AF_INET, SOCK_STREAM, 0);

   if( connect(dstSocket, (struct sockaddr *) &dstAddr, sizeof(dstAddr)))
   {
      // Failed to connect
      connectCheck = 3;
    }
    else
    {
      // Success with connection
      connectCheck = 8;
    }

}

#endif /* MDL_START */

------------------------------------------------------------------------

I put the server block and the client block on the same model file. Is it the reason of freezing Matlab? I think this is not the good way to initialize the socket between two blocks.

If someone inform me any clue, it would be great help.

Answer 1

[Ankit Desai]

This blog post might be helpful in trying to establish a server/client connection using TCPIP.

Remember, once you open (using fopen) the server socket, it will wait indefinitely for a connection. MATLAB will wait until an incoming connection is established.

It is therefore best to keep server and client on separate machines.

Hope this helps

-Ankit

[Sangkyun Kim]

Now, I separated the server with the different process of execution file, not Matlab.

And, it works without problem. I think I need more practice with the socket programming.

Thanks for your advice.