用select实现的简单聊天室

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>

#include <vector>
#include <string>
using namespace std;

int main(int argc,char* argv[])
{
printf("server start up\n");

if(argc <= 3)
{
printf("usage:%s ip port backlog\n",basename(argv[0]));
return 1;
}

//IP地址
const char* ip = argv[1];
//端口号
int port = atoi(argv[2]);
//内核监听队列的最大长度（完全连接的socket）
int backlog = atoi(argv[3]);

//创建socket	(TIP/IP协议族，流式socket)
int server_sockfd = socket(PF_INET,SOCK_STREAM,0);

//最大连接数，初始化为server_sockfd
int max_fd = server_sockfd;

//
vector<int>	 connFds;
connFds.reserve(backlog);

//TCP/IP协议族的socket地址结构体
struct sockaddr_in server_addr;
bzero(&server_addr,sizeof(server_addr));
server_addr.sin_family = AF_INET;			//TCP/IPv4的地址族
inet_pton(AF_INET,ip,&server_addr.sin_addr);	//将IP地址字符串转换为二进制的整数并赋给addr.sin_server_addr
server_addr.sin_port = htons(port);			//端口，host to net，将主机字节序（小端）转换为网络字节序（大端）

//将文件描述符sock和socket地址关联，仅服务端需要，客户端自动绑定地址
//注意需要强制转换为 struct sockaddr*
int ret = bind(server_sockfd,(struct sockaddr*)&server_addr,sizeof(server_addr));
assert(ret != -1);

//监听
ret = listen(server_sockfd,backlog);
assert(ret != -1);

//客户端地址信息
struct sockaddr_in client_addr;
socklen_t client_addrlength = sizeof(client_addr);

char buf[1024]={0};

//文件描述符集合
fd_set read_fds;
fd_set  exception_fds;
FD_ZERO(&read_fds);
FD_ZERO(&exception_fds);

//超时
//    struct timeval timeout;
//    timeout.tv_sec = 500;             //秒
//    timeout.tv_usec = 0 ;            //微秒

while(1)
{
FD_SET(server_sockfd,&read_fds);
for(int i =0;i<connFds.size();++i)
{
FD_SET(connFds[i],&read_fds);
FD_SET(connFds[i],&exception_fds);
}

int ret = select(max_fd+1,&read_fds,NULL,&exception_fds,NULL);
if( ret  ==  -1)
{
//printf("selection failure\n");
perror("select");
break;
}
else if( ret == 0)
{
perror("timeout");
break;
}

for(vector<int>::iterator it = connFds.begin();it != connFds.end();)
{
if( FD_ISSET(*it,&read_fds) )
{
memset(buf,0,sizeof(buf));
int ret = recv(*it,buf,sizeof(buf)-1,0);
if(ret <= 0)
{
perror("recv");
close(*it);
FD_CLR(*it,&read_fds);
printf("A client disconnectd\n");

it = connFds.erase(it);
continue;
}
else
{
buf[ret] = '\0';
printf("recived:%s\n",buf);

for(int i =0;i<connFds.size();++i)
{
if(connFds[i] != *it)
{
string str("some one said:");
str.append(buf);
int ret = send(connFds[i],str.c_str(),str.length(),0);
if(ret<=0)
{
perror("send");
}
}

}

}

}

++it;
}

for(vector<int>::iterator it = connFds.begin();it != connFds.end();++it)
{
if(FD_ISSET(*it,&exception_fds))
{
memset(buf,0,sizeof(buf));
int ret = recv(*it,buf,sizeof(buf)-1,MSG_OOB);
if(ret < 0)
{
perror("exception");
}
else
{
buf[ret] = '\0';
printf("%s",buf);
}

}
}

if( FD_ISSET(server_sockfd,&read_fds) )
{
//接受连接,并将被接受的远端sock地址信息保存在第二个参数中
int newfd = accept(server_sockfd,(struct sockaddr*)&client_addr,&client_addrlength);

if(newfd < 0)
{
perror("accept");
close(newfd);
return -1;
}
else
{
connFds.push_back(newfd);
max_fd = newfd;
//inet_ntoa(struct addr_in) 将IP地址转换为字符串并返回
//只是从监听队列中取出连接，即使客户端已经断开网络连接也会accept成功
printf("accept client_addr %s\n",inet_ntoa(client_addr.sin_addr));
}
}

}

//关闭连接，实际只是socket的引用-1,必须引用为0才会真正关闭
for(int i= 0;i< connFds.size();++i)
{
close(connFds[i]);
}

close(server_sockfd);
return 0;
}

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

#include <string>
#include <iostream>
using namespace std;

int main(int argc,char* argv[])
{
if(argc <= 2)
{
printf("usage:%s ip port\n",basename(argv[0]));
return 1;
}

const char* ip = argv[1];
int port = atoi(argv[2]);

struct sockaddr_in remote_addr;
bzero(&remote_addr,sizeof(remote_addr));
remote_addr.sin_family = AF_INET;
inet_pton(AF_INET,ip,&remote_addr.sin_addr);
remote_addr.sin_port = htons(port);

int remote_sockfd = socket(PF_INET,SOCK_STREAM,0);
assert(remote_sockfd>=0);

//连接
if(connect(remote_sockfd,(struct sockaddr*)&remote_addr,sizeof(struct sockaddr)) < 0)
{
perror("connect:");
return -1;
}
else
{
printf("connect success\n");
}

//文件描述符集合
fd_set read_fds;
FD_ZERO(&read_fds);

FD_SET(remote_sockfd,&read_fds);
//add stand input device
FD_SET(0,&read_fds);

int ret= -1;
string str;
char  buf[1024]={0};

while (1)
{
FD_SET(remote_sockfd,&read_fds);
FD_SET(0,&read_fds);//add stand input device

ret = select(remote_sockfd+1,&read_fds,NULL,NULL,NULL);
if(ret < 0)
{
perror("select");
}

if(FD_ISSET(remote_sockfd,&read_fds))
{
ret = recv(remote_sockfd,buf,sizeof(buf),0);
if(ret > 0)
{
str.clear();
buf[ret] = '\0';
str.append(buf);
cout<<str<<endl;
}

}

if(FD_ISSET(0,&read_fds))
{
memset(buf,0,sizeof(buf));
scanf("%s",buf);
ret = send(remote_sockfd,buf,strlen(buf),0);
if(ret<=0)
{
perror("send");
}
else
{
str.clear();
str = str+"send: "+buf+"success\n";
cout<<str;
}
}

}

close(remote_sockfd);
}