mfc thread에서 socket 보낼때 오류 attach

1.요약

CSocket / CAsyncSocket을 생성한 곳이 아닌 다른 Thread로 넘겨 처리할 경우 CSocket이 가진 Thread state가 변해 에러가 발생합니다.

예를들어 한쪽에서는 Listen을 하여 클라이언트 Socket을 Accept하고, Thread를 생성시켜 Socket전송을 맡길 경우에 Thread문제를 해결하는 방법을 소개하겠습니다.


2.본문

방법은 간단합니다.
Accept한 Socket을 Deatch시키고 거기에서 나온 handle을 Thread로 넘김니다.
그리고 Thread에서 handle을 Attach시켜 CSocket / CAsyncSocket 개체 인스턴스를 만들어 사용하면 됩니다. 

[출처] CSocket 과 CAsyncSocket에서 Thread문제|작성자 행님

CSocket::Attach

Call this member function to attach the hSocket handle to a CSocket object.

BOOL Attach(
   SOCKET hSocket 
);

Parameters

hSocket

Contains a handle to a socket.

Return Value

Nonzero if the function is successful.

Remarks

The SOCKET handle is stored in the object's m_hSocket data member.

For more information, see Windows Sockets: Using Sockets with Archives. Also see Windows Sockets Programming Considerations in the Platform SDK.

Example

// ...
class CSockThread : public CWinThread
{
// ... Other function and member declarations
protected:
  CSocket m_sConnected;
};

SOCKET hConnected;

BOOL CSockThread::InitInstance()
{
   // Attach the socket object to the socket handle
   // in the context of this thread.
   m_sConnected.Attach(hConnected);

   return TRUE;
}

// This listening socket has been constructed
// in the primary thread.
void CListeningSocket::OnAccept(int nErrorCode)
{
   // This CSocket object is used just temporarily
   // to accept the incoming connection.
   CSocket sConnected;
   Accept(sConnected);

   // Detach the newly accepted socket and save
   // the SOCKET handle.
   hConnected = sConnected.Detach();

   // After detaching it, it should no longer be
   // used in the context of this thread.

   // Start the other thread.
   AfxBeginThread(RUNTIME_CLASS(CSockThread));
}

See Also

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclib/html/_mfc_csocket.3a3a.attach.asp

[출처] NDK csocket thread|작성자 spjt