8.5 UDP Echo Client: main Function


8.5 UDP Echo Client: main Function

The UDP client main function is shown in Figure 8.7.

Figure 8.7 UDP echo client.

udpcliserv/udpcli01.c

 1 #include     "unp.h"  2 int  3 main(int argc, char **argv)  4 {  5     int     sockfd;  6     struct sockaddr_in servaddr;  7     if(argc != 2)  8        err_quit("usage: udpcli <IPaddress>");  9     bzero(&servaddr, sizeof(servaddr)); 10     servaddr.sin_family = AF_INET; 11     servaddr.sin_port = htons(SERV_PORT); 12     Inet_pton(AF_INET, argv[1], &servaddr.sin_addr); 13     sockfd = Socket(AF_INET, SOCK_DGRAM, 0); 14     dg_cli(stdin, sockfd, (SA *) &servaddr, sizeof(servaddr)); 15     exit(0); 16 } 

Fill in socket address structure with server's address

9 “12 An IPv4 socket address structure is filled in with the IP address and port number of the server. This structure will be passed to dg_cli , specifying where to send datagrams.

13 “14 A UDP socket is created and the function dg_cli is called.



UNIX Network Programming Volume 1, Third Edition
Unix Network Programming, Volume 1: The Sockets Networking API (3rd Edition)
ISBN: 0131411551
EAN: 2147483647
Year: 2003
Pages: 441

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net