[완료] recvfrom 함수 질문

	WSADATA			wsaData;
	SOCKET			sock;
	SOCKADDR_IN		servAddr;
	SOCKADDR_IN		ack;
	int			nRet=0;
	int			nAckLen=0;
	int			nRecvLen=0;
	char			lpBuf[BUF_SIZE]={0};
 
	//  
	if (WSAStartup(MAKEWORD(2,2), &wsaData) == SOCKET_ERROR)
	{
		m_strErr.Format(_T("WSAStartup() error: %d"), WSAGetLastError());
		AfxMessageBox(m_strErr, MB_OK, 0);
		WSACleanup();
	}
 
	// get socket
	sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 
	if (sock == INVALID_SOCKET)
	{
		m_strErr.Format(_T("socket() error: %d"), WSAGetLastError());
		AfxMessageBox(m_strErr, MB_OK, 0);
		WSACleanup();
	}
 
	servAddr.sin_family=AF_INET;
	servAddr.sin_addr.s_addr=htonl(INADDR_ANY);
	servAddr.sin_port=htons(5000);
 
	// bind()
	nRet = bind(sock, (SOCKADDR *) &servAddr, sizeof(servAddr));
 
	if (nRet == -1) {
		m_strErr.Format(_T("bind() error: %d"), WSAGetLastError());
		AfxMessageBox(m_strErr, MB_OK, 0);
		closesocket(sock);
		WSACleanup();
	}
 
	// listen
	nRecvLen = recvfrom(sock, lpBuf, 4096, 0, (SOCKADDR *)&ack, &nAckLen);
 
	if (nRecvLen == SOCKET_ERROR) {
		m_strErr.Format(_T("recvfrom() error: %d"), WSAGetLastError());
		AfxMessageBox(m_strErr, 0, 0);
 
        ....
}