搭建select的TCP客户端
#include <stdio.h>
#include <head.h>
#include <string.h>
#include <stdlib.h>
#define PORT 6666
#define IP "192.168.112.40"
int main(int argc, const char *argv[])
{
//创建流式套接字
int cfd = socket(AF_INET, SOCK_STREAM, 0);
if(cfd < 0)
{
Err("socket");
return -1;
}
printf("cfd = %d\n",cfd);
//绑定客户端的IP和端口————>非必须绑定
//若不绑定,则操作系统会给客户端绑定上客户端所在的主机IP,以及随机端口(49151~65535)
//填充地址消息结构体,真实的地址信息结构体根据地址族制定
//AF_INET:man 7 ip
//要连接哪个服务器,就填对应的服务器的IP和端口
struct sockaddr_in sin;
sin.sin_family = AF_INET; //必须填AF_INET
sin.sin_port = htons(PORT); //端口号:1024~49151
sin.sin_addr.s_addr = inet_addr(IP); //本机IP ifconfig查看
//连接服务器
if(connect(cfd,(struct sockaddr*)&sin,sizeof(sin)) < 0)
{
Err("connect");
return -1;
}
printf("connect ok\n");
//创建一个读集合
fd_set readfds, tempfds;
FD_ZERO(&readfds);
FD_ZERO(&tempfds);
FD_SET(0, &readfds);
FD_SET(cfd, &readfds);
int maxfd = cfd;
char buf[128] = "";
ssize_t res = 0;
int s_res = -1;
int newfd = -1;
while(1)
{
tempfds = readfds;
//调用IO多路复用函数 select()
s_res = select(maxfd + 1, &tempfds, NULL, NULL, NULL);
if(s_res < 0)
{
Err("select");
return -1;
}
else if(0 == s_res)
{
printf("time out...\n");
break;
}
if(FD_ISSET(0, &tempfds))
{
printf("触发键盘输入事件\n");
bzero(buf,sizeof(buf));
fgets(buf,sizeof(buf),stdin);
buf[strlen(buf)-1]=0;
//发送数据
res = send(cfd, buf, sizeof(buf), 0);
if(res < 0)
{
Err("send");
return -1;
}
}
if(FD_ISSET(cfd, &tempfds))
{
printf("触发服务器交互事件\n");
bzero(buf,sizeof(buf));
//接收数据
res = recv(cfd, buf, sizeof(buf), 0);
if(res < 0)
{
Err("recv");
return -1;
}
else if(0 == res)
{
printf("[%s :%d]cfd = %d 服务器掉线\n", IP, PORT, cfd);
break;
}
printf("[%s :%d]cfd = %d : %s\n", IP, PORT, cfd, buf);
}
}
close(cfd);
return 0;
}
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