GCC下的BSD Socket简单使用

GCC下的BSD Socket简单使用

亲手在用GCC编过没问题。之前老是写成C++的，要用G++才能编得过。
包含头文件：
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <netdb.h>
#include <fcntl.h>

服务器篇：
int createUdpServer()
{
int  g_socketSrv;//最好弄成全局的。
 struct sockaddr_in addrSrv;
 memset(&addrSrv,0,sizeof(struct sockaddr_in));
 addrSrv.sin_family = AF_INET; 
 addrSrv.sin_addr.s_addr=inet_addr("127.0.0.1"); 
 addrSrv.sin_port  = htons(20000); 
 
 if((g_socketSrv = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
        return -1;
//绑定socket
     if (-1 == bind(g_socketSrv, (struct sockaddr*)&addrSrv, sizeof(struct sockaddr_in))) 
     { 
         close(g_socketSrv);
  g_socketSrv = -1;
  return -1;    
     }
//设置堵塞模式
 int flags = fcntl(g_socketSrv, F_GETFL, 0);
 fcntl(g_socketSrv, F_SETFL, flags & ~O_NONBLOCK);
//循环收数据
   struct sockaddr_in addrClient; 
    int len = sizeof(struct sockaddr_in);
    int err = -1;
    while (1) {
  char recvBuf[256];
  memset(recvBuf, 0, sizeof(char)*256);
  recvfrom(g_socketSrv, recvBuf, 256, 0, (struct sockaddr*) &addrClient, (socklen_t*)&len); 
  int len2 = strlen(recvBuf); 
  if(len2>0)
  {
   //收到数据。。。recvBuf
  }
  sleep(2); 
    }

}

客户端：
-void sendMsg()
{
 int sock_fd;
 struct sockaddr_in receiver_addr;
 int port = 20000;
char palam[200];
strcpy(palam,http://www.baidu.com/);
 if((sock_fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
    {
     }
 receiver_addr.sin_family = AF_INET;
 receiver_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
 receiver_addr.sin_port = htons(port);
//就发送一条信息
 int ret = sendto(sock_fd, palam, strlen(palam), 0,(struct sockaddr*)&receiver_addr,sizeof(receiver_addr));
 if (-1 == ret) 
 {  
  //sendto error";
 }
 close(sock_fd);
}

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