/* * This program creates a socket and initiates a connection with * the socket given in the command line. One message is sent over * the connection and then the socket is closed, ending the * connection. The form of the command line is streamwrite * hostname portnumber. */ #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <netdb.h> #include <stdio.h> #define DATA "Half a league, half a league..." main(argc, argv) int argc; char *argv[]; { int sock; struct sockaddr_in server; struct hostent *hp, *gethostbyname(); char buf[1024];
/* Create socket. */ sock = socket(AF_INET, SOCK_STREAM, 0); if (sock < 0) { perror("opening stream socket"); exit(1); } /* Connect socket using name specified by command line. */ server.sin_family = AF_INET; server.sin_len = sizeof(server); hp = gethostbyname(argv[1]); if (hp == 0) { fprintf(stderr, "%s: unknown host", argv[1]); exit(2); } bcopy(hp->h_addr, &server.sin_addr, hp->h_length); server.sin_port = htons(atoi(argv[2]));
if (connect(sock, (struct sockaddr *)&server, sizeof(server)) < 0) { perror("connecting stream socket"); exit(1); } if (write(sock, DATA, sizeof(DATA)) < 0) perror("writing on stream socket"); close(sock); }