网络编程 单纯UDP通信

网络编程 单纯udp通信

1，udp发送端

2，udp接收端

udp发送端：

#include <stdio.h>
#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;

  if(argc != 2){
    return 1;
  }

  sock = socket(af_inet, sock_dgram, 0);
  addr.sin_family = af_inet;
  addr.sin_port = htons(12345);
  inet_pton(af_inet, argv[1], &addr.sin_addr.s_addr);

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

发送端的执行方式：

./a.out 127.0.0.1

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;
}

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