#include "unp.h" int main(int argc, char **argv) { int sockfd, n; char recvline[MAXLINE + 1]; socklen_t salen; struct sockaddr *sa; if (argc != 3) err_quit("usage: daytimeudpcli1 "); sockfd = Udp_client(argv[1], argv[2], (void **) &sa, &salen); printf("sending to %s\n", Sock_ntop_host(sa, salen)); Sendto(sockfd, "", 1, 0, sa, salen); /* send 1-byte datagram */ n = Recvfrom(sockfd, recvline, MAXLINE, 0, NULL, NULL); recvline[n] = '\0'; /* null terminate */ Fputs(recvline, stdout); exit(0); }