1 #include "apue.h" 2 static void sig_alarm(int); 3 void do_cli(int sockfd,FILE* fp,(SA*)pserveraddr,socklen_t servlen) 4 { 5 char sendbuf[maxlen],recvbuf[maxlen]; 6 int n; 7 while((fgets(sendbuf,maxlen,fp))!=NULL) 8 { 9 singal(SIGALRM,sig_alrm); //register an signal exec function 10 sendto(sockfd,sendbuf,strlen(sendbuf),0,pserveraddr,servlen); 11 alarm(5); 12 if((n=recvfrom(sockfd,recvbuf,maxlen,0,NULL,NULL))<0) 13 { 14 if(errno==EINTR) //time out 15 { 16 fprintf(stderr,"time out 5 sec! "); 17 } 18 else{ //recv error 19 perror("recv error! "); 20 } 21 } 22 else 23 { 24 alarm(0); // turn off alarm . we have successed recv a message; 25 recvbuf[n]='