// Run like this: simple_client address port // Results in argv ["./simple_client", "address", "port"] #include #include #include #include #include #include #include #include #include int main(int argc, char ** argv){ if(argc < 4){ printf("Usage: %s hostname port message\n", argv[0]); return 1; } struct sockaddr_in sad; sad.sin_port = htons(atoi(argv[2])); sad.sin_family = AF_INET; int skt = socket(AF_INET, SOCK_DGRAM, 0); struct hostent* entry = gethostbyname(argv[1]); if(!entry){ if(h_errno == HOST_NOT_FOUND){ printf("This is our own message that says the host wasn't found\n"); } herror("gethostbyname"); return 1; } struct in_addr **addr_list = (struct in_addr**)entry->h_addr_list; struct in_addr* c_addr = addr_list[0]; char* ip_string = inet_ntoa(*c_addr); sad.sin_addr = *c_addr; printf("Sending to: %s\n", ip_string); sendto(skt, argv[3], strlen(argv[3]), 0, (struct sockaddr*)&sad, sizeof(sad)); char message[256]; size_t actual_length = read(skt, message, 256); printf("Received message(%lu bytes): %s\n", actual_length, message); return 0; }