boost asio 채팅 소스 질문염 ㅠ

void PostSend( const bool bImmediately, const int nSize, char* pData )
	{
		char* pSendData = nullptr;
 
		EnterCriticalSection(&m_lock);		// 락 시작
 
		if( bImmediately == false ) // 이 변수의 의미는ㄴ .. ㅠㅠ
		{
			pSendData = new char[nSize];
			memcpy( pSendData, pData, nSize);
 
			m_SendDataQueue.push_back( pSendData );
		}
		else
		{
			pSendData = pData;
		}
 
		if( bImmediately || m_SendDataQueue.size() < 2 )
		{
			boost::asio::async_write( m_Socket, boost::asio::buffer( pSendData, nSize ),
									 boost::bind( &ChatClient::handle_write, this,
										boost::asio::placeholders::error,
										boost::asio::placeholders::bytes_transferred )
									);
		}
 
		LeaveCriticalSection(&m_lock);		// 락 완료
	}
 
void handle_receive( const boost::system::error_code& error, size_t bytes_transferred )
	{
		if( error )
		{
			if( error == boost::asio::error::eof )
			{
				std::cout << "클라이언트와 연결이 끊어졌습니다" << std::endl;
			}
			else 
			{
				std::cout << "error No: " << error.value() << " error Message: " << error.message() << std::endl;
			}
 
			Close();
		}
		else
		{
			memcpy( &m_PacketBuffer[ m_nPacketBufferMark ], m_ReceiveBuffer.data(), bytes_transferred );
 
			int nPacketData = m_nPacketBufferMark + bytes_transferred; // 
			int nReadData = 0; // 이 두 라인과 
 
			while( nPacketData > 0 )
			{
				if( nPacketData < sizeof(PACKET_HEADER) ) // 이 조건문은 왜 필요한 거죠??
				{
					break;
				}
 
				PACKET_HEADER* pHeader = (PACKET_HEADER*)&m_PacketBuffer[nReadData];
 
				if( pHeader->nSize <= nPacketData )
				{
					ProcessPacket( &m_PacketBuffer[nReadData] );
 
					nPacketData -= pHeader->nSize;
					nReadData += pHeader->nSize;
				}
				else
				{
					break;
				}
			}
 
			if( nPacketData > 0 )
			{
				char TempBuffer[MAX_RECEIVE_BUFFER_LEN] = {0,};
				memcpy( &TempBuffer[ 0 ], &m_PacketBuffer[nReadData], nPacketData );
				memcpy( &m_PacketBuffer[ 0 ], &TempBuffer[0], nPacketData );
			}
 
			m_nPacketBufferMark = nPacketData;
 
 
			PostReceive(); 
		}
	}
 
	void ProcessPacket( const char*pData )
	{
		PACKET_HEADER* pheader = (PACKET_HEADER*)pData;
 
		switch( pheader->nID )
		{
		case RES_IN:
			{
				PKT_RES_IN* pPacket = (PKT_RES_IN*)pData;
 
				LoginOK();
 
				std::cout << "클라이언트 로그인 성공 ?: " << pPacket->bIsSuccess << std::endl; 
			}
			break;
		case NOTICE_CHAT:
			{
				PKT_NOTICE_CHAT* pPacket = (PKT_NOTICE_CHAT*)pData;
 
				std::cout << pPacket->szName << ": " << pPacket->szMessage << std::endl; 
			}
			break;
		}
	}