linux socket编程 udp connect例子

#include <stdarg.h>
#include <stdio.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <sys/select.h>
#include <math.h>

void process_client(int s) {

char buff[128];
int rc,maxfd;
while(fgets(buff,sizeof(buff),stdin)!=NULL) {
write(s,buff,strlen(buff));
rc = read(s,buff,sizeof(buff));
if(rc <= 0)
error(1,0,"no data!!/n");
buff[rc]='/0';
write(1,buff,rc);
bzero(buff,sizeof(buff));
}

}

int main(int argc, char **argv) {
struct sockaddr_in server,temp;
char *hname, *sname;
int s, c, len;
if(argc < 2)
error(1,0,"parameters less than 2/n");
else if(argc == 2) {
hname = NULL;
sname = argv[1];
}
else if(argc == 3) {
hname = argv[1];
sname = argv[2];
}

s = client_connect(hname, sname, &server, "udp",1);
printf("%s,%d",inet_ntoa(server.sin_addr),ntohs(server.sin_port));
process_client(s);
close(s);
exit(0);
}