SOCKET SELECT

Question

select会检测不到包吗？
如果TCP将包一次性发过来 能正常检测到，
如果TCP将包分两次发过来，SELECT有时检测不到包，这是怎么回事？

Answer 1

应该不会吧，程序逻辑处理有问题吧，用select好久了，没有听说有lz的这种问题哦，

Answer 2

DWORD WINAPI CClientSocket::RecvThread(LPVOID lpParameter)
{
TRACE(_T("接收数据线程启动 \n")); CClientSocket *pClientSocket = (CClientSocket *)lpParameter;
  TRACE(_T("SOCKET Handle:%d in Thread \n"),pClientSocket->m_hClientSocket);
int nRet = connect(pClientSocket->m_hClientSocket,(sockaddr *)&(pClientSocket->m_SAI),sizeof(sockaddr));
  if (nRet == SOCKET_ERROR)
{
pClientSocket->m_strLastError.Format(_T("创建连接socket发生错误，错误信息:%d"),WSAGetLastError());
 
TRACE( pClientSocket->m_strLastError);
TRACE(_T("  in RecvThread \n")); closesocket(pClientSocket->m_hClientSocket);
pClientSocket->m_hClientSocket = NULL; PostMessage(pClientSocket->m_hMainWnd,WM_CONNECTMSG,0,0);
return -1;

} pClientSocket->m_IsSocketConnect = TRUE;
PostMessage(pClientSocket->m_hMainWnd,WM_CONNECTMSG,1,0);
TRACE(_T("服务器连接成功 \n"));

pClientSocket->m_nConnectionCount = 0;
TRACE(_T("连接成功据，设置为0 \n")); if (!pClientSocket->SendRegistration())
return -1; while (pClientSocket->m_hClientSocket)
{

TRACE(_T("等待返回的数据 \n")); fd_set RecvFS;
FD_ZERO(&RecvFS);
FD_SET(pClientSocket->m_hClientSocket,&RecvFS);

struct timeval timeout;
timeout.tv_sec = WAITTIME;
timeout.tv_usec = 0;

nRet = select(pClientSocket->m_hClientSocket+1,&RecvFS,NULL,NULL,&timeout);
if (nRet == SOCKET_ERROR) //select函数执行错误
{
pClientSocket->m_strLastError.Format(_T("监听Socket进行select出错,错误原因:%d"),WSAGetLastError());
break;
}
else
if (nRet == 0) //
{
TRACE(_T("监听Socket进行select等待超时\n"));
pClientSocket->m_strLastError.Format(_T("监听Socket进行select等待超时"));
}
else
{
if (FD_ISSET(pClientSocket->m_hClientSocket,&RecvFS))
{


nRet = recv(pClientSocket->m_hClientSocket,(char *)pClientSocket->m_pRecvBuffer+pClientSocket->m_nRecvBufferPos,RECVBUFFER_SIZE-pClientSocket->m_nRecvBufferPos,0);
if (nRet == SOCKET_ERROR)
{
if (pClientSocket->m_hClientSocket != NULL)
{

shutdown(pClientSocket->m_hClientSocket ,SD_BOTH );

closesocket(pClientSocket->m_hClientSocket);
pClientSocket->m_hClientSocket = NULL;

}
pClientSocket->m_nConnectionCount = -1;
pClientSocket->m_IsSocketConnect = FALSE;

PostMessage(pClientSocket->m_hMainWnd,WM_DISCONNECTMSG,2,0); //客户端异常主动断开

pClientSocket->m_strLastError.Format(_T("通信异常中断,错误代码:%d"),WSAGetLastError());
AfxMessageBox(pClientSocket->m_strLastError);
break;
}

if (nRet==0)
{
if (pClientSocket->m_hClientSocket != NULL)
{

shutdown(pClientSocket->m_hClientSocket ,SD_BOTH );

closesocket(pClientSocket->m_hClientSocket);
pClientSocket->m_hClientSocket = NULL;

}
pClientSocket->m_nConnectionCount = -1;
pClientSocket->m_IsSocketConnect = FALSE; PostMessage(pClientSocket->m_hMainWnd,WM_DISCONNECTMSG,3,0);  //服务器端主动断开

pClientSocket->m_strLastError.Format(_T("服务器端关闭连接"));
 break;
}

  TRACE(_T("收到数据，设置为0 \n"));
pClientSocket->m_nConnectionCount = 0;

if ( !pClientSocket->CheckPacket(nRet) )
break;
}
}
} //end-while return 0;
}