请、教一下在socket编程中connect()函数链接问题，谢谢！

Question

winsock编程中，我用的socket是非阻塞的，现在我要问的是，在非阻塞的情况下，函数一执行就会返回，那么如果我调用connect（）函数后，他还没有链接上服务器就返回了，最后他该怎样连接服务器呢？ 我理解阻塞的工作方式，一直等到链接之后才返回，不知道是不是这样的，请各位socket编程高手帮帮我，谢谢！！！

Answer 1

直接用就好了嘛~~
1.简单服务器
//#include <winsock2.h>
//#pragma comment(lib,"WS2_32.lib")
WSADATA wsd;
static UINT port=%%1;
UINT Listen(LPVOID pParam)
{
SOCKET sServer,sClient;
char buf[1024];
int retVal;
if(WSAStartup(MAKEWORD(2,2),&wsd)!=0)
{
return -1;//失败
}
sServer=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if(INVALID_SOCKET==sServer)
{
WSACleanup();
return -1;//创建套接字失败
}
SOCKADDR_IN addrServ;
addrServ.sin_family=AF_INET;
addrServ.sin_port=htons((short)pParam);
addrServ.sin_addr.s_addr=INADDR_ANY;
retVal=bind(sServer,(LPSOCKADDR)&addrServ,sizeof(SOCKADDR_IN));
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
WSACleanup();
return -1;//绑定套接字失败
}
retVal=listen(sServer,1);
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
WSACleanup();
return -1;//开始监听失败
}
sockaddr_in addrClient;
int addrClientlen=sizeof(addrClient);
sClient=accept(sServer,(sockaddr FAR*)&addrClient,&addrClientlen);
if(INVALID_SOCKET==sClient)
{
closesocket(sServer);
WSACleanup();
return -1;//开始接受客户端连接失败
}
ZeroMemory(buf,sizeof(buf));
retVal=recv(sClient,buf,sizeof(buf),0);
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
closesocket(sClient);
WSACleanup();
return -1;//接收数据失败
}
CString %%2(buf);
closesocket(sServer);
closesocket(sClient);
WSACleanup();
return 0;
}
CWinThread *pThread=AfxBeginThread(Listen,&port);

2.简单客户端
//#include <winsock2.h>
//#pragma comment(lib,"WS2_32.lib")
WSADATA wsd;
SOCKET sHost;
SOCKADDR_IN servAddr;
char buf[1024];
int retVal;
if(WSAStartup(MAKEWORD(2,2),&wsd)!=0)
{
return -1;//失败
}
sHost=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if(INVALID_SOCKET==sHost)
{
WSACleanup();
return -1;//创建套接字失败
}
servAddr.sin_family=AF_INET;
servAddr.sin_addr.s_addr=inet_addr(%%3);
servAddr.sin_port=htons((short)%%2);
int nServAddlen=sizeof(servAddr);
retVal=connect(sHost,(LPSOCKADDR)&servAddr,sizeof(servAddr));
if(SOCKET_ERROR==retVal) {
closesocket(sHost);
WSACleanup();
return -1;//连接服务器失败
}
ZeroMemory(buf,sizeof(buf));
strcpy(buf,%%3);
retVal=send(sHost,buf,sizeof(buf),0);
if(SOCKET_ERROR==retVal)
{
closesocket(sHost);
WSACleanup();
return -1;//向服务器发送数据失败
}
closesocket(sHost);
WSACleanup();

3.获得本机IP
//#include <winsock2.h>
//#pragma comment(lib,"WS2_32.lib")
WSADATA wsd;
if(WSAStartup(MAKEWORD(2,2),&wsd)!=0)
{
return -1;//失败
}
char szHostname[100],szHostaddress[200];
if(gethostname(szHostname,sizeof(szHostname))!=SOCKET_ERROR)
{
HOSTENT *pHostEnt=gethostbyname(szHostname);
if(pHostEnt!=NULL){
sprintf(szHostaddress,"%d.%d.%d.%d",
( pHostEnt->h_addr_list[0][0]&0x00ff ),
( pHostEnt->h_addr_list[0][1]&0x00ff ),
( pHostEnt->h_addr_list[0][2]&0x00ff ),
( pHostEnt->h_addr_list[0][3]&0x00ff ));
}
}
else
return;
CString %%1(szHostaddress);

5.点对点通信
//#include <winsock2.h>
//#pragma comment(lib,"WS2_32.lib")
WSADATA wsd;
SOCKADDR_IN addrServ,addrServ2;
SOCKET sServer,sClient,sHost;
int retVal;
sockaddr_in addrClient;
char buf[1024];
static UINT port=%%2;
BOOL listenerRun=TRUE;
UINT Listen(LPVOID pParam)
{
addrServ.sin_family=AF_INET;
addrServ.sin_port=htons((UINT)pParam);
addrServ.sin_addr.s_addr=INADDR_ANY;
retVal=bind(sServer,(LPSOCKADDR)&addrServ,sizeof(SOCKADDR_IN));
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
WSACleanup();
return -1;//绑定套接字失败
}
retVal=listen(sServer,1);
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
WSACleanup();
return -1;//开始监听失败
}
int addrClientlen=sizeof(addrClient);
sClient=accept(sServer,(sockaddr FAR*)&addrClient,&addClientlen);
if(INVALID_SOCKET==sClient)
{
closesocket(sServer);
WSACleanup();
return -1;//接收客户端请求失败
}
while(listenerRun)
{
ZeroMemory(buf,sizeof(buf));
retVal=recv(sClient,buf,sizeof(buf));
if(SOCKET_ERROR==retVal)
{
closesocket(sServer);
closesocket(sClient);
WSACleanup();
return -1;//接收客户端数据失败
}
CString %%4(buf);
}
}
if(WSAStartup(MAKEWORD(2,2),&wsd)!=0)
{
return -1;//失败
}
sServer=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if(INVALID_SOCKET==sServer)
{
WSACleanup();
return -1;//创建套接字失败
}
CWinThread *pThread=AfxBeginThread(Listen,&port);
sHost=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if(INVALID_SOCKET==sHost)
{
WSACleanup();
return -1;//创建套接字失败
}
servAddr2.sin_family=AF_INET;
servAddr2.sin_addr.s_addr=inet_addr(%%1);
servAddr.sin_port=htons((short)%%3);
int nServerAddrlen=sizeof(servAddr2);
retVal=connect(sHost,(LPSOCKADDR)&servAddr2,sizeof(servAddr2));
if(SOCKET_ERROR==retVal)
{
closesocket(sHost);
WSACleanup();
return -1;//连接失败
}
zeroMemory(buf,sizeof(buf));
strcpy(buf,%%5);
retVal=send(sHost,buf,sizeof(buf),0);
if(SOCKET_ERROR==retVal)
{
closesocket(sHost);
WSACleanup();
return -1;//向发送数据失败
}
listenerRun=FALSE;
DWORD dwExitCode;
::GetExitCodeThread(pThread->m_hThread,&dwExitCode);
pThread=null;
closesocket(sServer);
closesocket(sClient);
closesocket(sHost);
WSACleanup();

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