Hi Experts, I'm writing a C program (cut/paste below) to establish a TCP socket connection from my Mac Pro to a Windows XP-based test instrument sitting next to it over LAN (Ethernet). The program compiles without any warnings or errors. But executing the code using GNU Debugger, I can see it exits at 'exit(2)' which is the "if(connect(MySocket" line. There's no timeout, it just exits immediately. I compile using: gcc -g -Wall talk2me.c -o talk2me but I don't get any hints in the output nor when debugging at to what might be the issue. I'm sure the 10.0.1.100 and port 5025 are correct (independently, using Matlab code I can communicate fine using these parameters). Any idea where else I could look to debug? Outside of the code itself, are there any other requirements (perhaps system-level) that need to be satisfied (like running the code from a certain directory, or setting a parameter in unix to allow connections, etc.)? It may be something obvious that I'm missing as I'm not that experienced in this. I can run a 'hello world' program fine, it that helps. -gkk Code: int main(void) { int MySocket; if((MySocket=socket(PF_INET,SOCK_STREAM,0))==-1) exit(1); struct in_addr { unsigned long s_addr; }; struct sockaddr_in { short int sin_family; // Address family unsigned short int sin_port; // Port number struct in_addr sin_addr; // Internet address unsigned char sin_zero[8]; // Padding }; struct sockaddr_in MyAddress; // Initialize the whole structure to zero memset(&MyAddress,0,sizeof(struct sockaddr_in)); // Then set the individual fields MyAddress.sin_family=PF_INET; // IPv4 MyAddress.sin_port=htons(5025); // Port number used by instrument MyAddress.sin_addr.s_addr=inet_addr("10.0.1.100"); // IP Address if(connect(MySocket,(struct sockaddr *) &MyAddress, sizeof(struct sockaddr_in))==-1) exit(2); // Send SCPI command if(send(MySocket,"*IDN?\n",6,0)==-1) exit(3); // Read response char buffer[200]; int actual; if((actual=recv(MySocket,&buffer[0],200,0))==-1) exit(4); buffer[actual]=0; // Add zero character (C string) printf("Instrument ID: %s\n",buffer); // Close socket if(close(MySocket)==-1) exit(99); return 0; }
