diff --git a/ftk/src/ftkunix.cpp b/ftk/src/ftkunix.cpp
index 6492619..546b664 100644
--- a/ftk/src/ftkunix.cpp
+++ b/ftk/src/ftkunix.cpp
@@ -1171,7 +1171,7 @@ RCODE F_FileHdl::directWrite(
 #ifndef FLM_NLM
 		else
 		{
-			struct aiocb *		pAio = pBufferObj->getAIOStruct();
+			struct aiocb *		pAio = ((F_IOBuffer *)pBufferObj)->getAIOStruct();
 			
 			f_memset( pAio, 0, sizeof( struct aiocb));
 			pAio->aio_lio_opcode = LIO_WRITE;
diff --git a/ftk/src/ftkwin.cpp b/ftk/src/ftkwin.cpp
index 5aa9de2..c7c4976 100644
--- a/ftk/src/ftkwin.cpp
+++ b/ftk/src/ftkwin.cpp
@@ -1303,8 +1303,8 @@ RCODE F_FileHdl::directWrite(
 			}
 			else
 			{
-				pOverlapped = pBufferObj->getOverlapped();
-				pBufferObj->setFileHandle( m_FileHandle);
+				pOverlapped = ((F_IOBuffer *)pBufferObj)->getOverlapped();
+				((F_IOBuffer *)pBufferObj)->setFileHandle( m_FileHandle);
 			}
 
 			if (!pOverlapped->hEvent)