this is the code,but after compile ,run .
it doesn't work.
use gdb debug,it stopped at recvfrom (line 24),no error return,but it
stopped,how can I do?

1 #include <sys/types.h
2 #include <sys/socket.h
3 #include <netinet/in.h
4 #include <arpa/inet.h
5 #include <stdio.h
6 #include <stdlib.h
7 #include <string.h
8 #define BUFFSIZE 150
9 //#define int socklen_t

10 int main()
11 {
12 struct sockaddr_in serv;
13 char buff[BUFFSIZE];
14 int sockfd,n;
15 if((sockfd = socket(PF_INET,SOCK_DGRAM,0)) <0)
16 printf("socket error");
17 bzero((char*)&serv ,sizeof(serv));
18 serv.sin_family=AF_INET;
19 serv.sin_addr.s_addr=inet_addr("64.233.189.104");
20 serv.sin_port=htons(13);

21 if(sendto(sockfd,buff,BUFFSIZE,0,
22 (struct sockaddr*)&serv,sizeof(serv))!=BUFFSIZE)
23 printf("sendto error");

24 if((n=recvfrom(sockfd,buff,BUFFSIZE,0,
25 (struct sockaddr*)NULL,(int*) NULL))<2)
26 printf("recvfrom error");
27 buff[n-2]=0;
28 printf("%s\n",buff);
29 // exit(0);
30 return 0;
31 }