用select管理套接字的状态，套接字可读的时候如何判断该SOCKET是可以接收数据，还是SOCKET关闭？

[chenkangli]

用select管理套接字的状态，套接字可读的时候如何判断该SOCKET是可以接收数据，还是SOCKET关闭？

[kugou123]

// Server.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "winsock.h"
#include "io.h"
#include "stdlib.h"
#include <vector>

using namespace std;

#pragma comment(lib,"WSOCK32")

int main(int argc, char* argv[])
{
int len;
char buff[255];
fd_set readfds;

memset(buff,0,sizeof(buff));

WSADATA wsdata;
WSAStartup(0x0202,&wsdata);
vector <SOCKET> SockList;
vector <SOCKET>::iterator Iter;

SOCKET ListenSocket,NewSocket;
sockaddr_in s_in,new_s_in;
s_in.sin_family = AF_INET;
s_in.sin_addr.s_addr = htonl(INADDR_ANY);
s_in.sin_port = htons(55555);

ListenSocket=socket(AF_INET,SOCK_STREAM,0);

if(ListenSocket==INVALID_SOCKET)
{
printf("\n Failed to setup socket!");
return 0;
}

bind(ListenSocket,(struct sockaddr * )&s_in,sizeof(s_in));

listen(ListenSocket,5);

printf("\n Waiting for client to connect...");

len=sizeof(new_s_in);

FD_ZERO(&readfds);
FD_SET(ListenSocket, &readfds);

int nRet;
for (;;)
{

nRet = select(0, &readfds, NULL, NULL, NULL);

// 判断监听套接字是否可读，如果可读，表示有连接请求
if (FD_ISSET(ListenSocket, &readfds))
{
NewSocket = accept(ListenSocket, (struct sockaddr *)&new_s_in,&len);

if(SockList.size()==63)
{
printf("此次连接被拒绝\n");
closesocket(NewSocket);
continue;
}

else
{

// 将套接字放入套接字容器

SockList.push_back(NewSocket);
}

}


for(Iter=SockList.begin();Iter!=SockList.end();)
{
if(FD_ISSET(*Iter, &readfds))
{
nRet = recv(*Iter, buff, sizeof(buff), 0);

if(nRet>0)
printf("\n %s", buff); // 输出接受到的数据

else
{
INT iError = ::WSAGetLastError();
if ((iError == WSAENETRESET ) ||
( iError == WSAECONNABORTED ) ||
( iError == WSAECONNRESET ) ||
( iError == WSAEINVAL ) ||
( nRet == 0 ) )
{ //表明客户端已经断开
closesocket(*Iter);
printf("\n Socket %d disconnect!",*Iter);
Iter=SockList.erase(Iter);
continue;
}
}

}
Iter++;
}

//更新套接字容器
FD_ZERO(&readfds);
FD_SET(ListenSocket, &readfds);
for(Iter=SockList.begin();Iter!=SockList.end();Iter++)
{
FD_SET(*Iter,&readfds);
}
}

return 0;
}