udp

UDP发送端：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21

#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main(int argc, char* argv[]){
  int sock
  sockaddr_in addr
  int n

  sock = socket(AF_INET, SOCK_DGRAM, 0)
  addr.sin_family = AF_INET
  addr.sin_port = htons(12345)
  inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr.s_addr)

  n = sendto(sock, "aaaaa", 5, 0, (sockaddr*)&addr, sizeof(addr))
  close(sock)
  return 0
}

UDP接收端

#include <stdio.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

int main(){
int sock;
sockaddr_in addr;
sockaddr_in senderinfo;
socklen_t addrlen;
char buf[2048];
int n;

sock = socket(AF_INET, SOCK_DGRAM, 0);

addr.sin_family = AF_INET;
addr.sin_port = htons(12345);
addr.sin_addr.s_addr = INADDR_ANY;

bind(sock, (sockaddr*)&addr, sizeof(addr));

addrlen = sizeof(senderinfo);

n = recvfrom(sock, buf, sizeof(buf) - 1, 0, (sockaddr*)&senderinfo, &addrlen);
write(fileno(stdout), buf, n);
close(sock);
return 0;
}