diff --git a/qse/cmd/awk/awk.c b/qse/cmd/awk/awk.c
index 1c21c095..80d941c0 100644
--- a/qse/cmd/awk/awk.c
+++ b/qse/cmd/awk/awk.c
@@ -29,6 +29,7 @@
 #include <qse/cmn/main.h>
 #include <qse/cmn/mbwc.h>
 #include <qse/cmn/xma.h>
+#include <qse/cmn/nwio.h>
 
 #include <string.h>
 #include <signal.h>
@@ -55,6 +56,10 @@
 #	include <errno.h>
 #endif
 
+
+
+#include <sys/socket.h>
+
 static qse_awk_rtx_t* app_rtx = QSE_NULL;
 static int app_debug = 0;
 
@@ -93,6 +98,11 @@ struct gvmv_t
 	qse_size_t  len;
 };
 
+struct rtx_xtn_t
+{
+	qse_awk_rio_fun_t old_pipe_handler;
+};
+
 static void dprint (const qse_char_t* fmt, ...)
 {
 	if (app_debug)
@@ -884,6 +894,101 @@ static qse_mmgr_t debug_mmgr =
 };
 #endif
 
+static qse_ssize_t nwio_handler (
+	qse_awk_rtx_t* rtx, qse_awk_rio_cmd_t cmd, qse_awk_rio_arg_t* riod,
+	qse_char_t* data, qse_size_t size, qse_nwad_t* nwad)
+{
+	switch (cmd)
+	{
+		case QSE_AWK_RIO_OPEN:
+		{
+			qse_nwio_t* handle;
+
+			handle = qse_nwio_open (
+				qse_awk_rtx_getmmgr(rtx), 0, nwad, 
+				QSE_NWIO_TEXT | QSE_NWIO_IGNOREMBWCERR |
+				QSE_NWIO_READNORETRY | QSE_NWIO_WRITENORETRY
+			);
+			if (handle == QSE_NULL) return -1;
+
+#if defined(QSE_CHAR_IS_WCHAR)
+			{
+				qse_cmgr_t* cmgr = qse_awk_rtx_getcmgrstd (rtx, riod->name);
+				if (cmgr)	qse_nwio_setcmgr (handle, cmgr);
+			}
+#endif
+
+			riod->handle = (void*)handle;
+			return 1;
+		}
+
+		case QSE_AWK_RIO_CLOSE:
+		{
+			qse_nwio_close ((qse_nwio_t*)riod->handle);
+			riod->handle = QSE_NULL;
+			return 0;
+		}
+
+		case QSE_AWK_RIO_READ:
+		{
+			return qse_nwio_read ((qse_nwio_t*)riod->handle, data, size);
+		}
+
+		case QSE_AWK_RIO_WRITE:
+		{
+			return qse_nwio_write ((qse_nwio_t*)riod->handle, data, size);
+		}
+
+		case QSE_AWK_RIO_FLUSH:
+		{
+			/*if (riod->mode == QSE_AWK_RIO_PIPE_READ) return -1;*/
+			return qse_nwio_flush ((qse_nwio_t*)riod->handle);
+		}
+
+		case QSE_AWK_RIO_NEXT:
+		{
+			return -1;
+		}
+	}
+
+	return -1;
+}
+
+static qse_ssize_t new_pipe_handler (
+	qse_awk_rtx_t* rtx, qse_awk_rio_cmd_t cmd, qse_awk_rio_arg_t* riod,
+	qse_char_t* data, qse_size_t size)
+{
+	struct rtx_xtn_t* xtn;
+	qse_nwad_t nwad;
+	
+	xtn = qse_awk_rtx_getxtnstd (rtx);
+
+	if (qse_strtonwad (riod->name, &nwad) >= 0)
+		return nwio_handler (rtx, cmd, riod, data, size, &nwad);
+
+	return xtn->old_pipe_handler (rtx, cmd, riod, data, size);
+}
+
+static void extend_pipe_handler (qse_awk_rtx_t* rtx)
+{
+	struct rtx_xtn_t* xtn;
+	qse_awk_rio_t rio;
+
+	xtn = qse_awk_rtx_getxtnstd (rtx);
+
+	/* get the previous handler functions */
+	qse_awk_rtx_getrio (rtx, &rio); 
+
+	/* remember the old pipe handler function */
+	xtn->old_pipe_handler = rio.pipe;
+
+	/* change the pipe handler to a new one */
+	rio.pipe = new_pipe_handler;
+
+	/* changes the handlers with a new set */
+	qse_awk_rtx_setrio (rtx, &rio);
+}
+
 static int awk_main (int argc, qse_char_t* argv[])
 {
 	qse_awk_t* awk = QSE_NULL;
@@ -999,7 +1104,7 @@ static int awk_main (int argc, qse_char_t* argv[])
 #endif
 
 	rtx = qse_awk_rtx_openstd (
-		awk, 0, QSE_T("qseawk"),
+		awk, QSE_SIZEOF(struct rtx_xtn_t), QSE_T("qseawk"),
 		(const qse_char_t*const*)arg.icf, QSE_NULL, arg.console_cmgr);
 	if (rtx == QSE_NULL) 
 	{
@@ -1012,6 +1117,8 @@ static int awk_main (int argc, qse_char_t* argv[])
 		print_awkerr (awk);
 		goto oops;
 	}
+	
+	extend_pipe_handler (rtx);
 
 	app_rtx = rtx;
 #ifdef ENABLE_CALLBACK
diff --git a/qse/configure b/qse/configure
index 3ebfb13b..b91098fb 100755
--- a/qse/configure
+++ b/qse/configure
@@ -16002,7 +16002,7 @@ fi
 
 done
 
-for ac_header in time.h sys/time.h utime.h spawn.h
+for ac_header in time.h sys/time.h utime.h spawn.h execinfo.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
@@ -16015,7 +16015,7 @@ fi
 
 done
 
-for ac_header in sys/resource.h sys/wait.h sys/syscall.h sys/sendfile.h
+for ac_header in sys/resource.h sys/wait.h sys/syscall.h sys/sendfile.h sys/epoll.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
@@ -16028,18 +16028,6 @@ fi
 
 done
 
-for ac_header in execinfo.h
-do :
-  ac_fn_c_check_header_mongrel "$LINENO" "execinfo.h" "ac_cv_header_execinfo_h" "$ac_includes_default"
-if test "x$ac_cv_header_execinfo_h" = xyes; then :
-  cat >>confdefs.h <<_ACEOF
-#define HAVE_EXECINFO_H 1
-_ACEOF
-
-fi
-
-done
-
 
 ac_fn_c_check_type "$LINENO" "wchar_t" "ac_cv_type_wchar_t" "#include <stddef.h>
 "
@@ -16542,6 +16530,27 @@ fi
 fi
 
 
+
+$as_echo "#define HAVE_EPOLL /**/" >>confdefs.h
+
+for ac_func in epoll_create epoll_create1
+do :
+  as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
+ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
+if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
+  cat >>confdefs.h <<_ACEOF
+#define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
+_ACEOF
+
+fi
+done
+
+if test "$ac_cv_func_epoll_create" = "yes"
+then
+	$as_echo "#define HAVE_EPOLL 1" >>confdefs.h
+
+fi
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for main in -lunicows" >&5
 $as_echo_n "checking for main in -lunicows... " >&6; }
 if ${ac_cv_lib_unicows_main+:} false; then :
diff --git a/qse/configure.ac b/qse/configure.ac
index 2286d723..c0679957 100644
--- a/qse/configure.ac
+++ b/qse/configure.ac
@@ -83,9 +83,8 @@ AC_SUBST(LIBM, $LIBM)
 dnl check header files.
 AC_HEADER_STDC
 AC_CHECK_HEADERS([stddef.h wchar.h wctype.h errno.h signal.h fcntl.h])
-AC_CHECK_HEADERS([time.h sys/time.h utime.h spawn.h])
-AC_CHECK_HEADERS([sys/resource.h sys/wait.h sys/syscall.h sys/sendfile.h])
-AC_CHECK_HEADERS([execinfo.h])
+AC_CHECK_HEADERS([time.h sys/time.h utime.h spawn.h execinfo.h])
+AC_CHECK_HEADERS([sys/resource.h sys/wait.h sys/syscall.h sys/sendfile.h sys/epoll.h])
 
 dnl check data types
 AC_CHECK_TYPE([wchar_t], 
@@ -173,6 +172,13 @@ then
 fi
 AC_SUBST(SENDFILE_LIBS)
 
+AC_DEFINE(HAVE_EPOLL, [], [epoll support])
+AC_CHECK_FUNCS([epoll_create epoll_create1])
+if test "$ac_cv_func_epoll_create" = "yes"
+then
+	AC_DEFINE(HAVE_EPOLL, 1)
+fi
+
 dnl check is the import library for unicows.dll exists
 dnl this check doesn't look for a particular symbol
 dnl but for the symbol 'main' since i want to check 
diff --git a/qse/include/qse/awk/awk.h b/qse/include/qse/awk/awk.h
index 9a9fc6e8..14f834e0 100644
--- a/qse/include/qse/awk/awk.h
+++ b/qse/include/qse/awk/awk.h
@@ -1674,6 +1674,24 @@ void qse_awk_rtx_stop (
 	qse_awk_rtx_t* rtx /**< runtime context */
 );
 
+/**
+ * The qse_awk_rtx_getrio() function copies runtime I/O handlers
+ * to the memory buffer pointed to by @a rio.
+ */
+void qse_awk_rtx_getrio (
+	qse_awk_rtx_t* rtx,
+	qse_awk_rio_t* rio
+);
+
+/**
+ * The qse_awk_rtx_getrio() function sets runtime I/O handlers
+ * with the functions pointed to by @a rio.
+ */
+void qse_awk_rtx_setrio (
+	qse_awk_rtx_t*       rtx,
+	const qse_awk_rio_t* rio
+);
+
 /**
  * The qse_awk_rtx_poprcb() function pops a runtime callback set
  * and returns the pointer to it. If no callback set can be popped,
diff --git a/qse/include/qse/awk/std.h b/qse/include/qse/awk/std.h
index ab10d2c1..dbbb5ea6 100644
--- a/qse/include/qse/awk/std.h
+++ b/qse/include/qse/awk/std.h
@@ -166,12 +166,23 @@ qse_awk_rtx_t* qse_awk_rtx_openstd (
 );
 
 /**
- * The qse_awk_rtx_getxtnstd() gets the pointer to extension space.
+ * The qse_awk_rtx_getxtnstd() function gets the pointer to extension space.
  */
 void* qse_awk_rtx_getxtnstd (
 	qse_awk_rtx_t* rtx
 );
 
+
+/**
+ * The qse_awk_rtx_getcmgrstd() function gets the current character 
+ * manager associated with a particular I/O target indicated by the name 
+ * @a ioname.
+ */
+qse_cmgr_t* qse_awk_rtx_getcmgrstd (
+	qse_awk_rtx_t*    rtx,
+	const qse_char_t* ioname
+);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/qse/include/qse/cmn/Makefile.am b/qse/include/qse/cmn/Makefile.am
index 00881183..a78916ec 100644
--- a/qse/include/qse/cmn/Makefile.am
+++ b/qse/include/qse/cmn/Makefile.am
@@ -21,6 +21,7 @@ pkginclude_HEADERS = \
 	mbwc.h \
 	mem.h \
 	nwad.h \
+	nwio.h \
 	oht.h \
 	opt.h \
 	path.h \
diff --git a/qse/include/qse/cmn/Makefile.in b/qse/include/qse/cmn/Makefile.in
index de6dc6f8..ce829a7d 100644
--- a/qse/include/qse/cmn/Makefile.in
+++ b/qse/include/qse/cmn/Makefile.in
@@ -53,9 +53,9 @@ SOURCES =
 DIST_SOURCES =
 am__pkginclude_HEADERS_DIST = alg.h chr.h cp949.h cp950.h dll.h env.h \
 	fio.h fma.h fmt.h fs.h gdl.h htb.h hton.h ipad.h lda.h main.h \
-	map.h mbwc.h mem.h nwad.h oht.h opt.h path.h pio.h pma.h rbt.h \
-	rex.h sio.h sll.h slmb.h stdio.h str.h time.h tio.h tre.h \
-	utf8.h xma.h Mmgr.hpp StdMmgr.hpp Mmged.hpp
+	map.h mbwc.h mem.h nwad.h nwio.h oht.h opt.h path.h pio.h \
+	pma.h rbt.h rex.h sio.h sll.h slmb.h stdio.h str.h time.h \
+	tio.h tre.h utf8.h xma.h Mmgr.hpp StdMmgr.hpp Mmged.hpp
 am__vpath_adj_setup = srcdirstrip=`echo "$(srcdir)" | sed 's|.|.|g'`;
 am__vpath_adj = case $$p in \
     $(srcdir)/*) f=`echo "$$p" | sed "s|^$$srcdirstrip/||"`;; \
@@ -231,9 +231,9 @@ top_builddir = @top_builddir@
 top_srcdir = @top_srcdir@
 pkginclude_HEADERS = alg.h chr.h cp949.h cp950.h dll.h env.h fio.h \
 	fma.h fmt.h fs.h gdl.h htb.h hton.h ipad.h lda.h main.h map.h \
-	mbwc.h mem.h nwad.h oht.h opt.h path.h pio.h pma.h rbt.h rex.h \
-	sio.h sll.h slmb.h stdio.h str.h time.h tio.h tre.h utf8.h \
-	xma.h $(am__append_1)
+	mbwc.h mem.h nwad.h nwio.h oht.h opt.h path.h pio.h pma.h \
+	rbt.h rex.h sio.h sll.h slmb.h stdio.h str.h time.h tio.h \
+	tre.h utf8.h xma.h $(am__append_1)
 all: all-am
 
 .SUFFIXES:
diff --git a/qse/include/qse/cmn/nwio.h b/qse/include/qse/cmn/nwio.h
new file mode 100644
index 00000000..ecb50860
--- /dev/null
+++ b/qse/include/qse/cmn/nwio.h
@@ -0,0 +1,201 @@
+/*
+ * $Id$
+ *
+    Copyright 2006-2011 Chung, Hyung-Hwan.
+    This file is part of QSE.
+
+    QSE is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as 
+    published by the Free Software Foundation, either version 3 of 
+    the License, or (at your option) any later version.
+
+    QSE is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public 
+    License along with QSE. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _QSE_CMN_NWIO_H_
+#define _QSE_CMN_NWIO_H_
+
+/** @file
+ * This file defines a generic text I/O interface.
+ */
+
+#include <qse/types.h>
+#include <qse/macros.h>
+#include <qse/cmn/tio.h>
+#include <qse/cmn/nwad.h>
+
+enum qse_nwio_flag_t
+{
+	QSE_NWIO_TEXT          = (1 << 0),
+	QSE_NWIO_IGNOREMBWCERR = (1 << 1),
+	QSE_NWIO_NOAUTOFLUSH   = (1 << 2),
+
+	/* normal open flags */
+	QSE_NWIO_READ          = (1 << 8),
+	QSE_NWIO_WRITE         = (1 << 9),
+
+	/** do not reread if read has been interrupted */
+	QSE_NWIO_READNORETRY   = (1 << 10),
+	/** do not rewrite if write has been interrupted */
+	QSE_NWIO_WRITENORETRY  = (1 << 11),
+	QSE_NWIO_LISTEN        = (1 << 12)
+};
+
+enum qse_nwio_errnum_t
+{
+	QSE_NWIO_ENOERR = 0, /**< no error */
+
+	QSE_NWIO_ENOMEM,     /**< out of memory */
+	QSE_NWIO_EINVAL,     /**< invalid parameter */
+	QSE_NWIO_EACCES,     /**< access denied */
+	QSE_NWIO_ENOENT,     /**< no such file */
+	QSE_NWIO_EEXIST,     /**< already exist */
+	QSE_NWIO_EINTR,      /**< interrupted */
+	QSE_NWIO_EPIPE,      /**< broken pipe */
+	QSE_NWIO_ECONN,      /**< connection refused */
+	QSE_NWIO_EILSEQ,     /**< illegal sequence */
+	QSE_NWIO_EICSEQ,     /**< incomplete sequence */
+	QSE_NWIO_EILCHR,     /**< illegal character */
+	QSE_NWIO_ESYSERR,    /**< subsystem(system call) error */
+	QSE_NWIO_ENOIMPL,    /**< not implemented */
+
+	QSE_NWIO_EOTHER      /**< other error */
+};
+typedef enum qse_nwio_errnum_t qse_nwio_errnum_t;
+
+#if defined(_WIN32)
+/* TODO: */
+#elif defined(__OS2__)
+/* TODO: */
+#elif defined(__DOS__)
+/* TODO: */
+#else
+     typedef int qse_nwio_hnd_t; /**< defines a pipe handle type */
+#    define  QSE_NWIO_HND_NIL ((qse_nwio_hnd_t)-1)
+#endif
+
+typedef struct qse_nwio_t qse_nwio_t;
+
+struct qse_nwio_t
+{
+	QSE_DEFINE_COMMON_FIELDS (nwio)
+	int               flags;
+	qse_nwio_errnum_t errnum;
+	qse_nwio_hnd_t    handle;
+	qse_tio_t*        tio;
+};
+
+#define QSE_NWIO_HANDLE(nwio) ((nwio)->handle)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+QSE_DEFINE_COMMON_FUNCTIONS (nwio)
+
+/**
+ * The qse_nwio_open() function opens a file.
+ * To open a file, you should set the flags with at least one of
+ * QSE_NWIO_READ, QSE_NWIO_WRITE, QSE_NWIO_APPEND.
+ *
+ * If the #QSE_NWIO_HANDLE flag is set, the @a nwad parameter is interpreted
+ * as a pointer to qse_nwio_hnd_t.
+ */
+qse_nwio_t* qse_nwio_open (
+	qse_mmgr_t*       mmgr,
+	qse_size_t        ext,
+	const qse_nwad_t* nwad,
+	int               flags
+);
+
+/**
+ * The qse_nwio_close() function closes a file.
+ */
+void qse_nwio_close (
+	qse_nwio_t* nwio
+);
+
+/**
+ * The qse_nwio_close() function opens a file into @a nwio.
+ */
+int qse_nwio_init (
+	qse_nwio_t*       nwio,
+	qse_mmgr_t*       mmgr,
+	const qse_nwad_t* nwad,
+	int               flags
+);
+
+/**
+ * The qse_nwio_close() function finalizes a file by closing the handle 
+ * stored in @a nwio.
+ */
+void qse_nwio_fini (
+	qse_nwio_t* nwio
+);
+
+qse_nwio_errnum_t qse_nwio_geterrnum (
+	const qse_nwio_t* nwio
+);
+
+/**
+ * The qse_nwio_gethandle() function returns the native file handle.
+ */
+qse_nwio_hnd_t qse_nwio_gethandle (
+	const qse_nwio_t* nwio
+);
+
+qse_ubi_t qse_nwio_gethandleasubi (
+	const qse_nwio_t* nwio
+);
+
+
+qse_cmgr_t* qse_nwio_getcmgr (
+	qse_nwio_t* nwio
+);
+
+void qse_nwio_setcmgr (
+	qse_nwio_t* nwio,
+	qse_cmgr_t* cmgr
+);
+
+
+qse_ssize_t qse_nwio_flush (
+	qse_nwio_t*  nwio
+);
+
+void qse_nwio_purge (
+	qse_nwio_t*  nwio
+);
+
+/**
+ * The qse_nwio_read() function reads data.
+ */
+qse_ssize_t qse_nwio_read (
+	qse_nwio_t*  nwio,
+	void*        buf,
+	qse_size_t   size
+);
+
+/**
+ * The qse_nwio_write() function writes data.
+ * If QSE_NWIO_TEXT is used and the size parameter is (qse_size_t)-1,
+ * the function treats the data parameter as a pointer to a null-terminated
+ * string.
+ */
+qse_ssize_t qse_nwio_write (
+	qse_nwio_t*  nwio,
+	const void*  data,
+	qse_size_t   size
+);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/qse/include/qse/cmn/pio.h b/qse/include/qse/cmn/pio.h
index 3155f2f9..bee3ee1c 100644
--- a/qse/include/qse/cmn/pio.h
+++ b/qse/include/qse/cmn/pio.h
@@ -83,7 +83,16 @@ enum qse_pio_flag_t
 	/** drop stdout */
 	QSE_PIO_DROPOUT       = (1 << 17),
 	/** drop stderr */
-	QSE_PIO_DROPERR       = (1 << 18)
+	QSE_PIO_DROPERR       = (1 << 18),
+
+	/** do not reread if read has been interrupted */
+	QSE_PIO_READNORETRY   = (1 << 21), 
+	/** do not rewrite if write has been interrupted */
+	QSE_PIO_WRITENORETRY  = (1 << 22),
+	/** return immediately from qse_pio_wait() if a child has not exited */
+	QSE_PIO_WAITNOBLOCK   = (1 << 23),
+	/** do not wait again if waitpid has been interrupted */
+	QSE_PIO_WAITNORETRY   = (1 << 24)
 };
 
 /**
@@ -97,29 +106,6 @@ enum qse_pio_hid_t
 };
 typedef enum qse_pio_hid_t qse_pio_hid_t;
 
-/** 
- * The qse_pio_option_t type defines options to change the behavior of
- * qse_pio_xxx functions.
- */
-enum qse_pio_option_t
-{
-	/*QSE_PIO_READ_NOBLOCK   = (1 << 0),*/
-
-	/** do not reread if read has been interrupted */
-	QSE_PIO_READ_NORETRY   = (1 << 1), 
-
-	/*QSE_PIO_WRITE_NOBLOCK  = (1 << 2),*/
-
-	/** do not rewrite if write has been interrupted */
-	QSE_PIO_WRITE_NORETRY  = (1 << 3),
-
-	/** return immediately from qse_pio_wait() if a child has not exited */
-	QSE_PIO_WAIT_NOBLOCK   = (1 << 4),
-
-	/** do not wait again if waitpid has been interrupted */
-	QSE_PIO_WAIT_NORETRY   = (1 << 5)
-};
-
 /**
  * The qse_pio_errnum_t type defines error numbers.
  */
@@ -190,7 +176,7 @@ struct qse_pio_pin_t
 struct qse_pio_t
 {
 	QSE_DEFINE_COMMON_FIELDS(pio)
-	int              option;  /**< options */
+	int              flags;  /**< options */
 	qse_pio_errnum_t errnum;  /**< error number */
 	qse_pio_pid_t    child;   /**< handle to a child process */
 	qse_pio_pin_t    pin[3];
@@ -198,8 +184,6 @@ struct qse_pio_t
 
 /** access the @a errnum field of the #qse_pio_t structure */
 #define QSE_PIO_ERRNUM(pio)    ((pio)->errnum)
-/** access the @a option field of the #qse_pio_t structure */
-#define QSE_PIO_OPTION(pio)    ((pio)->option)
 /** access the @a child field of the #qse_pio_t structure */
 #define QSE_PIO_CHILD(pio)     ((pio)->child)
 /** get the native handle from the #qse_pio_t structure */
@@ -272,23 +256,6 @@ qse_pio_errnum_t qse_pio_geterrnum (
 	const qse_pio_t* pio /**< pio object */
 );
 
-/**
- * The qse_pio_getoption() function gets the current option.
- * @return option number OR'ed of #qse_pio_option_t enumerators
- */
-int qse_pio_getoption (
-	const qse_pio_t* pio    /**< pio object */
-);
-
-/**
- * The qse_pio_setoption() function sets the option.
- */ 
-void qse_pio_setoption (
-	qse_pio_t* pio, /**< pio object */
-	int        opt  /**< 0 or a number OR'ed of #qse_pio_option_t
-	                     enumerators */
-);
-
 /**
  * The qse_pio_getcmgr() function returns the current character manager.
  * It returns #QSE_NULL is @a pio is not opened with #QSE_PIO_TEXT.
@@ -368,6 +335,15 @@ qse_ssize_t qse_pio_flush (
 	qse_pio_hid_t hid  /**< handle ID */
 );
 
+/**
+ * The qse_pio_purge() drops unflushed input and output data in the 
+ * buffer. 
+ */
+void qse_pio_purge (
+	qse_pio_t*    pio, /**< pio object */
+	qse_pio_hid_t hid  /**< handle ID */
+);
+
 /**
  * The qse_pio_end() function closes a pipe to a child process
  */
diff --git a/qse/include/qse/cmn/sio.h b/qse/include/qse/cmn/sio.h
index 1593cb69..3e527436 100644
--- a/qse/include/qse/cmn/sio.h
+++ b/qse/include/qse/cmn/sio.h
@@ -99,15 +99,7 @@ struct qse_sio_t
 	QSE_DEFINE_COMMON_FIELDS (sio)
 	qse_sio_errnum_t errnum;
 
-	/*
-	depending on the stream type... FILE, FIFO, TCP, UDP
-	qse_sio_type_t type;
-	*/
-	union
-	{
-		qse_fio_t file;
-		int sck;
-	} u;
+	qse_fio_t file;
 
 	struct
 	{
@@ -126,30 +118,6 @@ struct qse_sio_t
 /** access the @a errnum field of the #qse_sio_t structure */
 #define QSE_SIO_ERRNUM(sio)    ((sio)->errnum)
 
-#if 0
-typedef struct qse_sio_uri_t qse_sio_uri_t;
-struct qse_sio_uri_t
-{
-	enum
-	{
-		QSE_SIO_FILE,
-		QSE_SIO_FIFO,
-		QSE_SIO_PIPE,
-		QSE_SIO_TCP,
-		QSE_SIO_UDP
-	};
-
-	union
-	{
-		const qse_char_t* file;
-		const qse_char_t* fifo;
-		/* nothing needed for pipe */
-	/*	qse_ipap_t        tcp;
-		qse_ipap_t        udp; */
-	} u;
-};
-#endif
-
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/qse/include/qse/conf_vms.h b/qse/include/qse/conf_vms.h
index 5617baf2..a8c4d73e 100644
--- a/qse/include/qse/conf_vms.h
+++ b/qse/include/qse/conf_vms.h
@@ -101,7 +101,19 @@
 #endif
 
 #define QSE_SIZEOF_WCHAR_T 4
+#define QSE_CHAR_IS_WCHAR
+ 
+#if defined(vax) || defined(__vax)
+#	define QSE_SIZEOF_OFF_T 4
+#elif defined(_LARGEFILE)
+#	define QSE_SIZEOF_OFF_T 8
+#else
+#	define QSE_SIZEOF_OFF_T 4
+#endif
 
+#define QSE_SIZEOF_OFF64_T     0
+#define QSE_SIZEOF_MBSTATE_T   24 
+#define QSE_MBLEN_MAX          8
 
 /* make sure you change these when you change 
  * the version in configure.ac */
diff --git a/qse/include/qse/config.h.in b/qse/include/qse/config.h.in
index 5d1c67da..6deddba9 100644
--- a/qse/include/qse/config.h.in
+++ b/qse/include/qse/config.h.in
@@ -55,6 +55,15 @@
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #undef HAVE_DLFCN_H
 
+/* epoll support */
+#undef HAVE_EPOLL
+
+/* Define to 1 if you have the `epoll_create' function. */
+#undef HAVE_EPOLL_CREATE
+
+/* Define to 1 if you have the `epoll_create1' function. */
+#undef HAVE_EPOLL_CREATE1
+
 /* Define to 1 if you have the <errno.h> header file. */
 #undef HAVE_ERRNO_H
 
@@ -263,6 +272,9 @@
    */
 #undef HAVE_SYS_DIR_H
 
+/* Define to 1 if you have the <sys/epoll.h> header file. */
+#undef HAVE_SYS_EPOLL_H
+
 /* Define to 1 if you have the <sys/ndir.h> header file, and it defines `DIR'.
    */
 #undef HAVE_SYS_NDIR_H
diff --git a/qse/lib/awk/rio.c b/qse/lib/awk/rio.c
index 739d80db..a4bffda7 100644
--- a/qse/lib/awk/rio.c
+++ b/qse/lib/awk/rio.c
@@ -135,6 +135,8 @@ static int find_rio_in (
 			return -1;
 		}
 
+		QSE_MEMSET (p, 0, QSE_SIZEOF(*p));
+
 		p->name = QSE_AWK_STRDUP (run->awk, name);
 		if (p->name == QSE_NULL)
 		{
@@ -146,6 +148,7 @@ static int find_rio_in (
 		p->type = (io_type | io_mask);
 		p->mode = io_mode;
 		p->rwcmode = QSE_AWK_RIO_CLOSE_FULL;
+		/*
 		p->handle = QSE_NULL;
 		p->next = QSE_NULL;
 		p->rwcstate = 0;
@@ -155,6 +158,7 @@ static int find_rio_in (
 		p->in.len = 0;
 		p->in.eof = 0;
 		p->in.eos = 0;
+		*/
 
 		qse_awk_rtx_seterrnum (run, QSE_AWK_ENOERR, QSE_NULL);
 
@@ -718,6 +722,8 @@ int qse_awk_rtx_writeio_str (
 			qse_awk_rtx_seterrnum (run, QSE_AWK_ENOMEM, QSE_NULL);
 			return -1;
 		}
+		
+		QSE_MEMSET (p, 0, QSE_SIZEOF(*p));
 
 		p->name = QSE_AWK_STRDUP (run->awk, name);
 		if (p->name == QSE_NULL)
@@ -730,12 +736,14 @@ int qse_awk_rtx_writeio_str (
 		p->type = (io_type | io_mask);
 		p->mode = io_mode;
 		p->rwcmode = QSE_AWK_RIO_CLOSE_FULL;
+		/*
 		p->handle = QSE_NULL;
 		p->next = QSE_NULL;
 		p->rwcstate = 0;
 
 		p->out.eof = 0;
 		p->out.eos = 0;
+		*/
 
 		qse_awk_rtx_seterrnum (run, QSE_AWK_ENOERR, QSE_NULL);
 		n = handler (run, QSE_AWK_RIO_OPEN, p, QSE_NULL, 0);
diff --git a/qse/lib/awk/run.c b/qse/lib/awk/run.c
index 65464c90..76dc9a4b 100644
--- a/qse/lib/awk/run.c
+++ b/qse/lib/awk/run.c
@@ -765,6 +765,20 @@ qse_bool_t qse_awk_rtx_isstop (qse_awk_rtx_t* rtx)
 	return (rtx->exit_level == EXIT_ABORT || rtx->awk->stopall);
 }
 
+void qse_awk_rtx_getrio (qse_awk_rtx_t* rtx, qse_awk_rio_t* rio)
+{
+	rio->pipe = rtx->rio.handler[QSE_AWK_RIO_PIPE];
+	rio->file = rtx->rio.handler[QSE_AWK_RIO_FILE];
+	rio->console = rtx->rio.handler[QSE_AWK_RIO_CONSOLE];
+}
+
+void qse_awk_rtx_setrio (qse_awk_rtx_t* rtx, const qse_awk_rio_t* rio)
+{
+	rtx->rio.handler[QSE_AWK_RIO_PIPE] = rio->pipe;
+	rtx->rio.handler[QSE_AWK_RIO_FILE] = rio->file;
+	rtx->rio.handler[QSE_AWK_RIO_CONSOLE] = rio->console;
+}
+
 qse_awk_rcb_t* qse_awk_rtx_poprcb (qse_awk_rtx_t* rtx)
 {
 	qse_awk_rcb_t* top = rtx->rcb;
@@ -917,7 +931,7 @@ static int init_rtx (qse_awk_rtx_t* rtx, qse_awk_t* awk, qse_awk_rio_t* rio)
 	}
 	else rtx->pattern_range_state = QSE_NULL;
 
-	if (rio != QSE_NULL)
+	if (rio)
 	{
 		rtx->rio.handler[QSE_AWK_RIO_PIPE] = rio->pipe;
 		rtx->rio.handler[QSE_AWK_RIO_FILE] = rio->file;
diff --git a/qse/lib/awk/std.c b/qse/lib/awk/std.c
index 4a5b789e..45e16e1d 100644
--- a/qse/lib/awk/std.c
+++ b/qse/lib/awk/std.c
@@ -91,11 +91,10 @@ typedef struct xtn_t
 				} str;
 			} u;
 		} out;
+	} s; /* script/source handling */
 
-	} s;
 } xtn_t;
 
-
 typedef struct rxtn_t
 {
 	unsigned int seed;	
@@ -124,11 +123,6 @@ typedef struct rxtn_t
 #endif
 } rxtn_t;
 
-#if defined(QSE_CHAR_IS_WCHAR)
-static qse_cmgr_t* getcmgr_from_cmgrtab (
-	qse_awk_rtx_t* rtx, const qse_char_t* ioname);
-#endif
-
 static qse_flt_t custom_awk_pow (qse_awk_t* awk, qse_flt_t x, qse_flt_t y)
 {
 #if defined(HAVE_POWL) && (QSE_SIZEOF_LONG_DOUBLE > QSE_SIZEOF_DOUBLE)
@@ -798,6 +792,7 @@ int qse_awk_parsestd (
 }
 
 /*** RTX_OPENSTD ***/
+
 static qse_ssize_t awk_rio_pipe (
 	qse_awk_rtx_t* rtx, qse_awk_rio_cmd_t cmd, qse_awk_rio_arg_t* riod,
 	qse_char_t* data, qse_size_t size)
@@ -811,7 +806,7 @@ static qse_ssize_t awk_rio_pipe (
 
 			if (riod->mode == QSE_AWK_RIO_PIPE_READ)
 			{
-				/* TODO: should we specify ERRTOOUT? */
+				/* TODO: should ERRTOOUT be unset? */
 				flags = QSE_PIO_READOUT | 
 				        QSE_PIO_ERRTOOUT;
 			}
@@ -825,7 +820,12 @@ static qse_ssize_t awk_rio_pipe (
 				        QSE_PIO_ERRTOOUT |
 				        QSE_PIO_WRITEIN;
 			}
-			else return -1; /* TODO: any way to set the error number? */
+			else 
+			{
+				/* this must not happen */
+				qse_awk_rtx_seterrnum (rtx, QSE_AWK_EINTERN, QSE_NULL);
+				return -1;
+			}
 
 			handle = qse_pio_open (
 				rtx->awk->mmgr,
@@ -838,7 +838,7 @@ static qse_ssize_t awk_rio_pipe (
 
 #if defined(QSE_CHAR_IS_WCHAR)
 			{
-				qse_cmgr_t* cmgr = getcmgr_from_cmgrtab (rtx, riod->name);
+				qse_cmgr_t* cmgr = qse_awk_rtx_getcmgrstd (rtx, riod->name);
 				if (cmgr)	
 				{
 					qse_pio_setcmgr (handle, QSE_PIO_IN, cmgr);
@@ -951,7 +951,7 @@ static qse_ssize_t awk_rio_file (
 
 #if defined(QSE_CHAR_IS_WCHAR)
 			{
-				qse_cmgr_t* cmgr = getcmgr_from_cmgrtab (rtx, riod->name);
+				qse_cmgr_t* cmgr = qse_awk_rtx_getcmgrstd (rtx, riod->name);
 				if (cmgr) qse_sio_setcmgr (handle, cmgr);
 			}
 #endif
@@ -1587,7 +1587,7 @@ static int fnc_time (qse_awk_rtx_t* rtx, const qse_cstr_t* fnm)
 }
 
 #if defined(QSE_CHAR_IS_WCHAR)
-static qse_cmgr_t* getcmgr_from_cmgrtab (
+qse_cmgr_t* qse_awk_rtx_getcmgrstd (
 	qse_awk_rtx_t* rtx, const qse_char_t* ioname)
 {
 	rxtn_t* rxtn;
diff --git a/qse/lib/cmn/Makefile.am b/qse/lib/cmn/Makefile.am
index aa4c909a..d0c80524 100644
--- a/qse/lib/cmn/Makefile.am
+++ b/qse/lib/cmn/Makefile.am
@@ -47,6 +47,7 @@ libqsecmn_la_SOURCES = \
 	mbwc-str.c \
 	mem.c \
 	nwad.c \
+	nwio.c \
 	oht.c \
 	opt.c \
 	path-basename.c \
diff --git a/qse/lib/cmn/Makefile.in b/qse/lib/cmn/Makefile.in
index fd2a96f8..fce9e5db 100644
--- a/qse/lib/cmn/Makefile.in
+++ b/qse/lib/cmn/Makefile.in
@@ -82,17 +82,18 @@ libqsecmn_la_LIBADD =
 am_libqsecmn_la_OBJECTS = alg-rand.lo alg-search.lo alg-sort.lo \
 	assert.lo chr.lo cp949.lo cp950.lo dll.lo env.lo gdl.lo htb.lo \
 	lda.lo fio.lo fma.lo fmt.lo fs.lo fs-err.lo fs-move.lo hton.lo \
-	ipad.lo main.lo mbwc.lo mbwc-str.lo mem.lo nwad.lo oht.lo \
-	opt.lo path-basename.lo path-canon.lo pio.lo pma.lo rbt.lo \
-	rex.lo sio.lo sll.lo slmb.lo stdio.lo str-beg.lo str-cat.lo \
-	str-chr.lo str-cnv.lo str-cmp.lo str-cpy.lo str-del.lo \
-	str-dup.lo str-dynm.lo str-dynw.lo str-end.lo str-excl.lo \
-	str-fcpy.lo str-fnmat.lo str-incl.lo str-len.lo str-pac.lo \
-	str-pbrk.lo str-put.lo str-rev.lo str-rot.lo str-set.lo \
-	str-spl.lo str-spn.lo str-str.lo str-subst.lo str-tok.lo \
-	str-trm.lo str-word.lo time.lo tio.lo tio-get.lo tio-put.lo \
-	tre.lo tre-ast.lo tre-compile.lo tre-match-backtrack.lo \
-	tre-match-parallel.lo tre-parse.lo tre-stack.lo utf8.lo xma.lo
+	ipad.lo main.lo mbwc.lo mbwc-str.lo mem.lo nwad.lo nwio.lo \
+	oht.lo opt.lo path-basename.lo path-canon.lo pio.lo pma.lo \
+	rbt.lo rex.lo sio.lo sll.lo slmb.lo stdio.lo str-beg.lo \
+	str-cat.lo str-chr.lo str-cnv.lo str-cmp.lo str-cpy.lo \
+	str-del.lo str-dup.lo str-dynm.lo str-dynw.lo str-end.lo \
+	str-excl.lo str-fcpy.lo str-fnmat.lo str-incl.lo str-len.lo \
+	str-pac.lo str-pbrk.lo str-put.lo str-rev.lo str-rot.lo \
+	str-set.lo str-spl.lo str-spn.lo str-str.lo str-subst.lo \
+	str-tok.lo str-trm.lo str-word.lo time.lo tio.lo tio-get.lo \
+	tio-put.lo tre.lo tre-ast.lo tre-compile.lo \
+	tre-match-backtrack.lo tre-match-parallel.lo tre-parse.lo \
+	tre-stack.lo utf8.lo xma.lo
 libqsecmn_la_OBJECTS = $(am_libqsecmn_la_OBJECTS)
 libqsecmn_la_LINK = $(LIBTOOL) --tag=CC $(AM_LIBTOOLFLAGS) \
 	$(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
@@ -326,6 +327,7 @@ libqsecmn_la_SOURCES = \
 	mbwc-str.c \
 	mem.c \
 	nwad.c \
+	nwio.c \
 	oht.c \
 	opt.c \
 	path-basename.c \
@@ -489,6 +491,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/mbwc.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/mem.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/nwad.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/nwio.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/oht.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/opt.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/path-basename.Plo@am__quote@
diff --git a/qse/lib/cmn/assert.c b/qse/lib/cmn/assert.c
index cc564d9b..4f0d9bec 100644
--- a/qse/lib/cmn/assert.c
+++ b/qse/lib/cmn/assert.c
@@ -40,6 +40,9 @@
 #elif defined(__DOS__)
 #	include <dos.h>
 #	include <dosfunc.h>
+#elif defined(vms) || defined(__vms)
+#	include <starlet.h> /* (SYS$...) */
+#	include <ssdef.h> /* (SS$...) */
 #else
 #	include "syscall.h"
 #endif
@@ -165,6 +168,9 @@ void qse_assert_failed (
 		regs.h.al = 249;
 		intdos (&regs, &regs);
 	}
+#elif defined(vms) || defined(__vms)
+	sys$exit (SS$_ABORT); /* this condition code can be shown with 
+	                       * 'show symbol $status' from the command-line. */
 #else
 	QSE_KILL (QSE_GETPID(), SIGABRT);
 	QSE_EXIT (1);
diff --git a/qse/lib/cmn/nwio.c b/qse/lib/cmn/nwio.c
new file mode 100644
index 00000000..e2e179c6
--- /dev/null
+++ b/qse/lib/cmn/nwio.c
@@ -0,0 +1,659 @@
+/*
+ * $Id$
+ *
+    Copyright 2006-2011 Chung, Hyung-Hwan.
+    This file is part of QSE.
+
+    QSE is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as 
+    published by the Free Software Foundation, either vernwion 3 of 
+    the License, or (at your option) any later vernwion.
+
+    QSE is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public 
+    License along with QSE. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <qse/cmn/nwio.h>
+#include "mem.h"
+
+#if defined(_WIN32)
+/* TODO: */
+#elif defined(__OS2__)
+/* TODO: */
+#elif defined(__DOS__)
+/* TODO: */
+#else
+#	include "syscall.h"
+#	include <sys/socket.h>
+#	include <netinet/in.h>
+#endif
+
+
+static qse_ssize_t socket_input (
+	qse_tio_t* tio, qse_tio_cmd_t cmd, void* buf, qse_size_t size);
+static qse_ssize_t socket_output (
+	qse_tio_t* tio, qse_tio_cmd_t cmd, void* buf, qse_size_t size);
+
+static int nwad_to_sockaddr (const qse_nwad_t* nwad, int* family, void* addr)
+{
+	int addrsize = -1;
+
+	switch (nwad->type)
+	{
+		case QSE_NWAD_IN4:
+		{
+			struct sockaddr_in* in; 
+
+			in = (struct sockaddr_in*)addr;
+			addrsize = QSE_SIZEOF(*in);
+			QSE_MEMSET (in, 0, addrsize);
+
+			*family = AF_INET;
+			in->sin_family = AF_INET;
+			in->sin_addr.s_addr = nwad->u.in4.addr.value;
+			in->sin_port = nwad->u.in4.port;
+			break;
+		}
+
+		case QSE_NWAD_IN6:
+		{
+#if defined(AF_INET6)
+			struct sockaddr_in6* in; 
+
+			in = (struct sockaddr_in6*)addr;
+			addrsize = QSE_SIZEOF(*in);
+			QSE_MEMSET (in, 0, addrsize);
+
+			*family = AF_INET6;
+			in->sin6_family = AF_INET6;
+			memcpy (&in->sin6_addr, &nwad->u.in6.addr, QSE_SIZEOF(nwad->u.in6.addr));
+			in->sin6_scope_id = nwad->u.in6.scope;
+			in->sin6_port = nwad->u.in6.port;
+#endif
+			break;
+		}
+	}
+
+	return addrsize;
+}
+
+#if defined(_WIN32)
+static qse_nwio_errnum_t syserr_to_errnum (DWORD e)
+{
+	switch (e)
+	{
+		case ERROR_NOT_ENOUGH_MEMORY:
+		case ERROR_OUTOFMEMORY:
+			return QSE_NWIO_ENOMEM;
+
+		case ERROR_INVALID_PARAMETER:
+		case ERROR_INVALID_HANDLE:
+		case ERROR_INVALID_NAME:
+			return QSE_NWIO_EINVAL;
+
+		case ERROR_ACCESS_DENIED:
+			return QSE_NWIO_EACCES;
+
+		case ERROR_FILE_NOT_FOUND:
+		case ERROR_PATH_NOT_FOUND:
+			return QSE_NWIO_ENOENT;
+
+		case ERROR_ALREADY_EXISTS:
+		case ERROR_FILE_EXISTS:
+			return QSE_NWIO_EEXIST;
+
+		case ERROR_BROKEN_PIPE:
+			return QSE_NWIO_EPIPE;
+
+		default:
+			return QSE_NWIO_ESYSERR;
+	}
+}
+#elif defined(__OS2__)
+static qse_nwio_errnum_t syserr_to_errnum (APIRET e)
+{
+	switch (e)
+	{
+		case ERROR_NOT_ENOUGH_MEMORY:
+			return QSE_NWIO_ENOMEM;
+
+		case ERROR_INVALID_PARAMETER:
+		case ERROR_INVALID_HANDLE:
+		case ERROR_INVALID_NAME:
+			return QSE_NWIO_EINVAL;
+
+		case ERROR_ACCESS_DENIED:
+			return QSE_NWIO_EACCES;
+
+		case ERROR_FILE_NOT_FOUND:
+		case ERROR_PATH_NOT_FOUND:
+			return QSE_NWIO_ENOENT;
+
+		case ERROR_ALREADY_EXISTS:
+			return QSE_NWIO_EEXIST;
+
+		case ERROR_BROKEN_PIPE:
+			return QSE_NWIO_EPIPE;
+
+		default:
+			return QSE_NWIO_ESYSERR;
+	}
+}
+#elif defined(__DOS__)
+static qse_nwio_errnum_t syserr_to_errnum (int e)
+{
+	switch (e)
+	{
+		case ENOMEM:
+			return QSE_NWIO_ENOMEM;
+
+		case EINVAL:
+			return QSE_NWIO_EINVAL;
+
+		case EACCES:
+			return QSE_NWIO_EACCES;
+
+		case ENOENT:
+			return QSE_NWIO_ENOENT;
+
+		case EEXIST:
+			return QSE_NWIO_EEXIST;
+		
+	
+		default:
+			return QSE_NWIO_ESYSERR;
+	}
+}
+#else
+static qse_nwio_errnum_t syserr_to_errnum (int e)
+{
+	switch (e)
+	{
+		case ENOMEM:
+			return QSE_NWIO_ENOMEM;
+
+		case EINVAL:
+			return QSE_NWIO_EINVAL;
+
+		case EACCES:
+			return QSE_NWIO_EACCES;
+
+		case ENOENT:
+			return QSE_NWIO_ENOENT;
+
+		case EEXIST:
+			return QSE_NWIO_EEXIST;
+	
+		case EINTR:
+			return QSE_NWIO_EINTR;
+
+		case EPIPE:
+			return QSE_NWIO_EPIPE;
+
+#if defined(ECONNREFUSED) || defined(ENETUNREACH)
+	#if defined(ECONNREFUSED) 
+		case ECONNREFUSED:
+	#endif
+	#if defined(ENETUNREACH) 
+		case ENETUNREACH:
+	#endif
+			return QSE_NWIO_ECONN;
+#endif
+
+		default:
+			return QSE_NWIO_ESYSERR;
+	}
+}
+#endif
+
+static qse_nwio_errnum_t tio_errnum_to_nwio_errnum (qse_tio_t* tio)
+{
+	switch (tio->errnum)
+	{
+		case QSE_TIO_ENOMEM:
+			return QSE_NWIO_ENOMEM;
+		case QSE_TIO_EINVAL:
+			return QSE_NWIO_EINVAL;
+		case QSE_TIO_EACCES:
+			return QSE_NWIO_EACCES;
+		case QSE_TIO_ENOENT:
+			return QSE_NWIO_ENOENT;
+		case QSE_TIO_EILSEQ:
+			return QSE_NWIO_EILSEQ;
+		case QSE_TIO_EICSEQ:
+			return QSE_NWIO_EICSEQ;
+		case QSE_TIO_EILCHR:
+			return QSE_NWIO_EILCHR;
+		default:
+			return QSE_NWIO_EOTHER;
+	}
+}
+
+qse_nwio_t* qse_nwio_open (
+	qse_mmgr_t* mmgr, qse_size_t xtnsize, const qse_nwad_t* nwad, int flags)
+{
+	qse_nwio_t* nwio;
+
+	nwio = QSE_MMGR_ALLOC (mmgr, QSE_SIZEOF(qse_nwio_t) + xtnsize);
+	if (nwio == QSE_NULL) return QSE_NULL;
+
+	if (qse_nwio_init (nwio, mmgr, nwad, flags) <= -1)
+	{
+		QSE_MMGR_FREE (mmgr, nwio);
+		return QSE_NULL;
+	}
+
+	return nwio;
+}
+
+void qse_nwio_close (qse_nwio_t* nwio)
+{
+	qse_nwio_fini (nwio);
+	QSE_MMGR_FREE (nwio->mmgr, nwio);
+}
+
+int qse_nwio_init (
+	qse_nwio_t* nwio, qse_mmgr_t* mmgr, const qse_nwad_t* nwad, int flags)
+{
+	union
+	{
+		struct sockaddr_in in4;
+		struct sockaddr_in6 in6;
+	} addr;
+	int addrlen;
+	int family;
+
+	QSE_MEMSET (nwio, 0, QSE_SIZEOF(*nwio));
+	nwio->mmgr = mmgr;
+	nwio->flags = flags;
+
+	addrlen = nwad_to_sockaddr (nwad, &family, &addr);
+
+#if defined(_WIN32)
+/* TODO: */
+#elif defined(__OS2__)
+/* TODO: */
+#elif defined(__DOS__)
+/* TODO: */
+#else
+	nwio->handle = socket (family, SOCK_STREAM, 0);
+	if (nwio->handle <= -1)
+	{
+		nwio->errnum = syserr_to_errnum (errno);
+		goto oops;
+	}
+
+#if defined(FD_CLOEXEC)
+	{ 
+		int tmp = fcntl (nwio->handle, F_GETFD);
+		if (tmp >= 0) fcntl (nwio->handle, F_SETFD, tmp | FD_CLOEXEC);
+	}
+#endif
+
+	if (flags & QSE_NWIO_LISTEN)
+	{
+		qse_nwio_hnd_t handle;
+
+		if (bind (nwio->handle, (struct sockaddr*)&addr, addrlen) <= -1 ||
+		    listen (nwio->handle, 10) <= -1)
+		{
+			nwio->errnum = syserr_to_errnum (errno);
+			goto oops;
+		}
+
+/* TODO: socklen_t */
+		handle = accept (nwio->handle, &addr, &addrlen);
+		if (handle <= -1)
+		{
+			nwio->errnum = syserr_to_errnum (errno);
+			goto oops;
+		}
+
+		close (nwio->handle);
+		nwio->handle = handle;
+	}
+	else
+	{
+		if (connect (nwio->handle, (struct sockaddr*)&addr, addrlen) <= -1)
+		{
+			nwio->errnum = syserr_to_errnum (errno);
+			goto oops;
+		}
+	}
+#endif
+
+	if (flags & QSE_NWIO_TEXT)
+	{
+		int topt = 0;
+
+		if (flags & QSE_NWIO_IGNOREMBWCERR) topt |= QSE_TIO_IGNOREMBWCERR;
+		if (flags & QSE_NWIO_NOAUTOFLUSH) topt |= QSE_TIO_NOAUTOFLUSH;
+
+		nwio->tio = qse_tio_open (mmgr, QSE_SIZEOF(qse_nwio_t*), topt);
+		if (nwio->tio == QSE_NULL)
+		{
+			nwio->errnum = QSE_NWIO_ENOMEM;
+			goto oops;
+		}
+
+		/* store the back-reference to nwio in the extension area.*/
+		*(qse_nwio_t**)QSE_XTN(nwio->tio) = nwio;
+
+		if (qse_tio_attachin (nwio->tio, socket_input, QSE_NULL, 4096) <= -1 ||
+		    qse_tio_attachout (nwio->tio, socket_output, QSE_NULL, 4096) <= -1)
+		{
+			if (nwio->errnum == QSE_NWIO_ENOERR) 
+				nwio->errnum = tio_errnum_to_nwio_errnum (nwio->tio);
+			goto oops;
+		}
+	}
+
+	return 0;
+
+oops:
+	if (nwio->tio) qse_tio_close (nwio->tio);
+
+#if defined(_WIN32)
+/* TODO: */
+#elif defined(__OS2__)
+/* TODO: */
+#elif defined(__DOS__)
+/* TODO: */
+#else
+	close (nwio->handle);
+#endif
+	return -1;
+}
+
+void qse_nwio_fini (qse_nwio_t* nwio)
+{
+	/*if (qse_nwio_flush (nwio) <= -1) return -1;*/
+	qse_nwio_flush (nwio);
+	if (nwio->tio)
+	{
+		qse_tio_close (nwio->tio);
+		nwio->tio = QSE_NULL;
+	}
+}
+
+qse_nwio_errnum_t qse_nwio_geterrnum (const qse_nwio_t* nwio)
+{
+	return nwio->errnum;
+}
+
+qse_cmgr_t* qse_nwio_getcmgr (qse_nwio_t* nwio)
+{
+	return nwio->tio? qse_tio_getcmgr (nwio->tio): QSE_NULL;
+}
+
+void qse_nwio_setcmgr (qse_nwio_t* nwio, qse_cmgr_t* cmgr)
+{
+	if (nwio->tio) qse_tio_setcmgr (nwio->tio, cmgr);
+}
+
+qse_nwio_hnd_t qse_nwio_gethandle (const qse_nwio_t* nwio)
+{
+	return QSE_NWIO_HANDLE(nwio);
+}
+
+qse_ubi_t qse_nwio_gethandleasubi (const qse_nwio_t* nwio)
+{
+	qse_ubi_t ubi;
+
+#if defined(_WIN32)
+/* TODO: */
+#elif defined(__OS2__)
+/* TODO: */
+#elif defined(__DOS__)
+/* TODO: */
+#else
+	ubi.i = nwio->handle;
+#endif
+	return ubi;
+}
+
+qse_ssize_t qse_nwio_flush (qse_nwio_t* nwio)
+{
+	qse_ssize_t n;
+
+	if (nwio->tio)
+	{
+		nwio->errnum = QSE_NWIO_ENOERR;
+		n = qse_tio_flush (nwio->tio);
+		if (n <= -1 && nwio->errnum == QSE_NWIO_ENOERR) 
+			nwio->errnum = tio_errnum_to_nwio_errnum (nwio->tio);
+	}
+	else n = 0;
+
+	return n;
+}
+
+void qse_nwio_purge (qse_nwio_t* nwio)
+{
+	if (nwio->tio) qse_tio_purge (nwio->tio);
+}
+
+/* ---------------------------------------------------------- */
+
+static qse_ssize_t nwio_read (qse_nwio_t* nwio, void* buf, qse_size_t size)
+{
+#if defined(_WIN32)
+	DWORD count;
+#elif defined(__OS2__)
+	ULONG count;
+	APIRET rc;
+#elif defined(__DOS__)
+	int n;
+#else
+	qse_ssize_t n;
+#endif
+
+#if defined(_WIN32)
+
+	if (size > (QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(DWORD)))
+		size = QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(DWORD);
+
+	if (ReadFile(nwio->handle, buf, (DWORD)size, &count, QSE_NULL) == FALSE) 
+	{
+		/* ReadFile receives ERROR_BROKEN_PIPE when the write end
+		 * is closed in the child process */
+		if (GetLastError() == ERROR_BROKEN_PIPE) return 0;
+		nwio->errnum = syserr_to_errnum(GetLastError());
+		return -1;
+	}
+	return (qse_ssize_t)count;
+
+#elif defined(__OS2__)
+
+	if (size > (QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(ULONG)))
+		size = QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(ULONG);
+
+	rc = DosRead (nwio->handle, buf, (ULONG)size, &count);
+	if (rc != NO_ERROR)
+	{
+    		if (rc == ERROR_BROKEN_PIPE) return 0; /* TODO: check this */
+		nwio->errnum = syserr_to_errnum(rc);
+    		return -1;
+    	}
+	return (qse_ssize_t)count;
+
+#elif defined(__DOS__)
+	/* TODO: verify this */
+
+	if (size > (QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(unsigned int)))
+		size = QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(unsigned int);
+
+	n = read (nwio->handle, buf, size);
+	if (n <= -1) nwio->errnum = syserr_to_errnum(errno);
+	return n;
+
+#else
+
+	if (size > (QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(size_t)))
+		size = QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(size_t);
+
+reread:
+	n = recv (nwio->handle, buf, size, 0);
+	if (n <= -1) 
+	{
+		if (errno == EINTR)
+		{
+			if (nwio->flags & QSE_NWIO_READNORETRY) 
+				nwio->errnum = QSE_NWIO_EINTR;
+			else goto reread;
+		}
+		else
+		{
+			nwio->errnum = syserr_to_errnum (errno);
+		}
+	}
+
+	return n;
+#endif
+}
+
+qse_ssize_t qse_nwio_read (qse_nwio_t* nwio, void* buf, qse_size_t size)
+{
+	if (nwio->tio == QSE_NULL) 
+		return nwio_read (nwio, buf, size);
+	else
+	{
+		qse_ssize_t n;
+
+		nwio->errnum = QSE_NWIO_ENOERR;
+		n = qse_tio_read (nwio->tio, buf, size);
+		if (n <= -1 && nwio->errnum == QSE_NWIO_ENOERR) 
+			nwio->errnum = tio_errnum_to_nwio_errnum (nwio->tio);
+
+		return n;
+	}
+}
+
+static qse_ssize_t nwio_write (qse_nwio_t* nwio, const void* data, qse_size_t size)
+{
+#if defined(_WIN32)
+	DWORD count;
+#elif defined(__OS2__)
+	ULONG count;
+	APIRET rc;
+#elif defined(__DOS__)
+	int n;
+#else
+	qse_ssize_t n;
+#endif
+
+#if defined(_WIN32)
+
+	if (size > (QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(DWORD)))
+		size = QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(DWORD);
+
+	if (WriteFile (nwio->handle, data, (DWORD)size, &count, QSE_NULL) == FALSE)
+	{
+		nwio->errnum = syserr_to_errnum(GetLastError());
+		return -1;
+	}
+	return (qse_ssize_t)count;
+
+#elif defined(__OS2__)
+
+	if (size > (QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(ULONG)))
+		size = QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(ULONG);
+
+	rc = DosWrite (nwio->handle, (PVOID)data, (ULONG)size, &count);
+	if (rc != NO_ERROR)
+	{
+		nwio->errnum = syserr_to_errnum(rc);
+    		return -1;
+	}
+	return (qse_ssize_t)count;
+
+#elif defined(__DOS__)
+
+	if (size > (QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(unsigned int)))
+		size = QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(unsigned int);
+
+	n = write (nwio->handle, data, size);
+	if (n <= -1) nwio->errnum = syserr_to_errnum (errno);
+	return n;
+
+#else
+
+	if (size > (QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(size_t)))
+		size = QSE_TYPE_MAX(qse_ssize_t) & QSE_TYPE_MAX(size_t);
+
+rewrite:
+	n = send (nwio->handle, data, size, 0);
+	if (n <= -1) 
+	{
+		if (errno == EINTR)
+		{
+			if (nwio->flags & QSE_NWIO_WRITENORETRY)
+				nwio->errnum = QSE_NWIO_EINTR;
+			else goto rewrite;
+		}
+		else
+		{
+			nwio->errnum = syserr_to_errnum (errno);
+		}
+	}
+	return n;
+
+#endif
+}
+
+qse_ssize_t qse_nwio_write (qse_nwio_t* nwio, const void* data, qse_size_t size)
+{
+	if (nwio->tio == QSE_NULL)
+		return nwio_write (nwio, data, size);
+	else
+	{
+		qse_ssize_t n;
+
+		nwio->errnum = QSE_NWIO_ENOERR;	
+		n = qse_tio_write (nwio->tio, data, size);
+		if (n <= -1 && nwio->errnum == QSE_NWIO_ENOERR) 
+			nwio->errnum = tio_errnum_to_nwio_errnum (nwio->tio);
+
+		return n;
+	}
+}
+
+/* ---------------------------------------------------------- */
+
+static qse_ssize_t socket_input (
+	qse_tio_t* tio, qse_tio_cmd_t cmd, void* buf, qse_size_t size)
+{
+	if (cmd == QSE_TIO_DATA) 
+	{
+		qse_nwio_t* nwio;
+
+		nwio = *(qse_nwio_t**)QSE_XTN(tio);
+		QSE_ASSERT (nwio != QSE_NULL);
+
+		return nwio_read (nwio, buf, size);
+	}
+
+	return 0;
+}
+
+static qse_ssize_t socket_output (
+	qse_tio_t* tio, qse_tio_cmd_t cmd, void* buf, qse_size_t size)
+{
+	if (cmd == QSE_TIO_DATA) 
+	{
+		qse_nwio_t* nwio;
+
+		nwio = *(qse_nwio_t**)QSE_XTN(tio);
+		QSE_ASSERT (nwio != QSE_NULL);
+
+		return nwio_write (nwio, buf, size);
+	}
+
+	return 0;
+}
+
diff --git a/qse/lib/cmn/pio.c b/qse/lib/cmn/pio.c
index 6ba91fab..02563559 100644
--- a/qse/lib/cmn/pio.c
+++ b/qse/lib/cmn/pio.c
@@ -575,6 +575,7 @@ int qse_pio_init (
 
 	QSE_MEMSET (pio, 0, QSE_SIZEOF(*pio));
 	pio->mmgr = mmgr;
+	pio->flags = flags;
 
 #if defined(_WIN32)
 	/* http://msdn.microsoft.com/en-us/library/ms682499(VS.85).aspx */
@@ -1886,7 +1887,6 @@ create_process:
 		}
 	}
 
-	pio->option = 0;
 	return 0;
 
 oops:
@@ -1961,8 +1961,9 @@ void qse_pio_fini (qse_pio_t* pio)
 	qse_pio_end (pio, QSE_PIO_OUT);
 	qse_pio_end (pio, QSE_PIO_IN);
 
-	pio->option &= ~QSE_PIO_WAIT_NOBLOCK;
-	pio->option &= ~QSE_PIO_WAIT_NORETRY;
+	/* when closing, enable blocking and retrying */
+	pio->flags &= ~QSE_PIO_WAITNOBLOCK;
+	pio->flags &= ~QSE_PIO_WAITNORETRY;
 	qse_pio_wait (pio);
 }
 
@@ -1971,16 +1972,6 @@ qse_pio_errnum_t qse_pio_geterrnum (const qse_pio_t* pio)
 	return pio->errnum;
 }
 
-int qse_pio_getoption (const qse_pio_t* pio)
-{
-	return pio->option;
-}
-
-void qse_pio_setoption (qse_pio_t* pio, int opt)
-{
-	pio->option = opt;
-}
-
 qse_cmgr_t* qse_pio_getcmgr (qse_pio_t* pio, qse_pio_hid_t hid)
 {
 	return pio->pin[hid].tio? 
@@ -2090,7 +2081,7 @@ reread:
 	{
 		if (errno == EINTR)
 		{
-			if (pio->option & QSE_PIO_READ_NORETRY) 
+			if (pio->flags & QSE_PIO_READNORETRY) 
 				pio->errnum = QSE_PIO_EINTR;
 			else goto reread;
 		}
@@ -2188,7 +2179,7 @@ rewrite:
 	{
 		if (errno == EINTR)
 		{
-			if (pio->option & QSE_PIO_WRITE_NORETRY)
+			if (pio->flags & QSE_PIO_WRITENORETRY)
 				pio->errnum = QSE_PIO_EINTR;
 			else goto rewrite;
 		}
@@ -2235,9 +2226,14 @@ qse_ssize_t qse_pio_flush (qse_pio_t* pio, qse_pio_hid_t hid)
 	return n;
 }
 
+void qse_pio_purge (qse_pio_t* pio, qse_pio_hid_t hid)
+{
+	if (pio->pin[hid].tio) qse_tio_purge (pio->pin[hid].tio);
+}
+
 void qse_pio_end (qse_pio_t* pio, qse_pio_hid_t hid)
 {
-	if (pio->pin[hid].tio != QSE_NULL)
+	if (pio->pin[hid].tio)
 	{
 		qse_tio_close (pio->pin[hid].tio);
 		pio->pin[hid].tio = QSE_NULL;
@@ -2271,7 +2267,7 @@ int qse_pio_wait (qse_pio_t* pio)
 	}
 
 	w = WaitForSingleObject (pio->child, 
-		((pio->option & QSE_PIO_WAIT_NOBLOCK)? 0: INFINITE)
+		((pio->flags & QSE_PIO_WAITNOBLOCK)? 0: INFINITE)
 	);
 	if (w == WAIT_TIMEOUT)
 	{
@@ -2327,7 +2323,7 @@ int qse_pio_wait (qse_pio_t* pio)
 
 	rc = DosWaitChild (
 		DCWA_PROCESSTREE,
-		((pio->option & QSE_PIO_WAIT_NOBLOCK)? DCWW_NOWAIT: DCWW_WAIT),
+		((pio->flags & QSE_PIO_WAITNOBLOCK)? DCWW_NOWAIT: DCWW_WAIT),
 		&child_rc,
 		&ppid,
 		pio->child
@@ -2367,7 +2363,7 @@ int qse_pio_wait (qse_pio_t* pio)
 		return -1;
 	}
 
-	if (pio->option & QSE_PIO_WAIT_NOBLOCK) opt |= WNOHANG;
+	if (pio->flags & QSE_PIO_WAITNOBLOCK) opt |= WNOHANG;
 
 	while (1)
 	{
@@ -2385,7 +2381,7 @@ int qse_pio_wait (qse_pio_t* pio)
 			}
 			else if (errno == EINTR)
 			{
-				if (pio->option & QSE_PIO_WAIT_NORETRY) 
+				if (pio->flags & QSE_PIO_WAITNORETRY) 
 					pio->errnum = QSE_PIO_EINTR;
 				else continue;
 			}
@@ -2397,7 +2393,7 @@ int qse_pio_wait (qse_pio_t* pio)
 		if (n == 0) 
 		{
 			/* when WNOHANG is not specified, 0 can't be returned */
-			QSE_ASSERT (pio->option & QSE_PIO_WAIT_NOBLOCK);
+			QSE_ASSERT (pio->flags & QSE_PIO_WAITNOBLOCK);
 
 			ret = 255 + 1;
 			/* the child process is still alive */
diff --git a/qse/lib/cmn/sio.c b/qse/lib/cmn/sio.c
index cbd250fc..6bf2565c 100644
--- a/qse/lib/cmn/sio.c
+++ b/qse/lib/cmn/sio.c
@@ -44,11 +44,6 @@ static qse_ssize_t file_input (
 static qse_ssize_t file_output (
 	qse_tio_t* tio, qse_tio_cmd_t cmd, void* buf, qse_size_t size);
 
-static qse_ssize_t socket_input (
-	qse_tio_t* tio, qse_tio_cmd_t cmd, void* buf, qse_size_t size);
-static qse_ssize_t socket_output (
-	qse_tio_t* tio, qse_tio_cmd_t cmd, void* buf, qse_size_t size);
-
 static qse_sio_errnum_t fio_errnum_to_sio_errnum (qse_fio_t* fio)
 {
 	switch (fio->errnum)
@@ -129,7 +124,7 @@ qse_sio_t* qse_sio_openstd (
 	if (sio) 
 	{
 		DWORD mode;
-		if (GetConsoleMode (sio->u.file.handle, &mode) == TRUE &&
+		if (GetConsoleMode (sio->file.handle, &mode) == TRUE &&
 		    GetConsoleOutputCP() == CP_UTF8)
 		{
 			sio->status |= STATUS_UTF8_CONSOLE;
@@ -163,10 +158,10 @@ int qse_sio_init (
 	 * this function, a user can specify a sio flag enumerator not 
 	 * present in the fio flag enumerator. mask off such an enumerator. */
 	if (qse_fio_init (
-		&sio->u.file, mmgr, file, 
+		&sio->file, mmgr, file, 
 		(flags & ~QSE_FIO_RESERVED), mode) <= -1) 
 	{
-		sio->errnum = fio_errnum_to_sio_errnum (&sio->u.file);
+		sio->errnum = fio_errnum_to_sio_errnum (&sio->file);
 		return -1;
 	}
 
@@ -176,7 +171,7 @@ int qse_sio_init (
 	if (qse_tio_init(&sio->tio.io, mmgr, topt) <= -1)
 	{
 		sio->errnum = tio_errnum_to_sio_errnum (&sio->tio.io);
-		qse_fio_fini (&sio->u.file);
+		qse_fio_fini (&sio->file);
 		return -1;
 	}
 	/* store the back-reference to sio in the extension area.*/
@@ -189,7 +184,7 @@ int qse_sio_init (
 		if (sio->errnum == QSE_SIO_ENOERR) 
 			sio->errnum = tio_errnum_to_sio_errnum (&sio->tio.io);
 		qse_tio_fini (&sio->tio.io);	
-		qse_fio_fini (&sio->u.file);
+		qse_fio_fini (&sio->file);
 		return -1;
 	}
 
@@ -211,7 +206,7 @@ int qse_sio_initstd (
 	if (n >= 0) 
 	{
 		DWORD mode;
-		if (GetConsoleMode (sio->u.file.handle, &mode) == TRUE &&
+		if (GetConsoleMode (sio->file.handle, &mode) == TRUE &&
 		    GetConsoleOutputCP() == CP_UTF8)
 		{
 			sio->status |= STATUS_UTF8_CONSOLE;
@@ -227,7 +222,7 @@ void qse_sio_fini (qse_sio_t* sio)
 	/*if (qse_sio_flush (sio) <= -1) return -1;*/
 	qse_sio_flush (sio);
 	qse_tio_fini (&sio->tio.io);
-	qse_fio_fini (&sio->u.file);
+	qse_fio_fini (&sio->file);
 }
 
 qse_sio_errnum_t qse_sio_geterrnum (const qse_sio_t* sio)
@@ -247,13 +242,13 @@ void qse_sio_setcmgr (qse_sio_t* sio, qse_cmgr_t* cmgr)
 
 qse_sio_hnd_t qse_sio_gethandle (const qse_sio_t* sio)
 {
-	/*return qse_fio_gethandle (&sio->u.file);*/
-	return QSE_FIO_HANDLE(&sio->u.file);
+	/*return qse_fio_gethandle (&sio->file);*/
+	return QSE_FIO_HANDLE(&sio->file);
 }
 
 qse_ubi_t qse_sio_gethandleasubi (const qse_sio_t* sio)
 {
-	return qse_fio_gethandleasubi (&sio->u.file);
+	return qse_fio_gethandleasubi (&sio->file);
 }
 
 qse_ssize_t qse_sio_flush (qse_sio_t* sio)
@@ -453,7 +448,7 @@ qse_ssize_t qse_sio_putwcs (qse_sio_t* sio, const qse_wchar_t* str)
 		for (cur = str, left = qse_wcslen(str); left > 0; cur += count, left -= count)
 		{
 			if (WriteConsoleW (
-				sio->u.file.handle, cur, left,
+				sio->file.handle, cur, left,
 				&count, QSE_NULL) == FALSE) 
 			{
 				sio->errnum = QSE_SIO_ESYSERR;
@@ -506,7 +501,7 @@ qse_ssize_t qse_sio_putwcsn (
 		for (cur = str, left = size; left > 0; cur += count, left -= count)
 		{
 			if (WriteConsoleW (
-				sio->u.file.handle, cur, left, 
+				sio->file.handle, cur, left, 
 				&count, QSE_NULL) == FALSE) 
 			{
 				sio->errnum = QSE_SIO_ESYSERR;
@@ -544,10 +539,10 @@ int qse_sio_getpos (qse_sio_t* sio, qse_sio_pos_t* pos)
 {
 	qse_fio_off_t off;
 
-	off = qse_fio_seek (&sio->u.file, 0, QSE_FIO_CURRENT);
+	off = qse_fio_seek (&sio->file, 0, QSE_FIO_CURRENT);
 	if (off == (qse_fio_off_t)-1) 
 	{
-		sio->errnum = fio_errnum_to_sio_errnum (&sio->u.file);
+		sio->errnum = fio_errnum_to_sio_errnum (&sio->file);
 		return -1;
 	}
 
@@ -560,10 +555,10 @@ int qse_sio_setpos (qse_sio_t* sio, qse_sio_pos_t pos)
    	qse_fio_off_t off;
 
 	if (qse_sio_flush(sio) <= -1) return -1;
-	off = qse_fio_seek (&sio->u.file, pos, QSE_FIO_BEGIN);
+	off = qse_fio_seek (&sio->file, pos, QSE_FIO_BEGIN);
 	if (off == (qse_fio_off_t)-1)
 	{
-		sio->errnum = fio_errnum_to_sio_errnum (&sio->u.file);
+		sio->errnum = fio_errnum_to_sio_errnum (&sio->file);
 		return -1;
 	}
 
@@ -577,12 +572,12 @@ int qse_sio_seek (qse_sio_t* sio, qse_sio_seek_t pos)
 	 *       can move to the end of the stream also.... */
 
 	if (qse_sio_flush(sio) <= -1) return -1;
-	return (qse_fio_seek (&sio->u.file, 
+	return (qse_fio_seek (&sio->file, 
 		0, QSE_FIO_END) == (qse_fio_off_t)-1)? -1: 0;
 
 	/* TODO: write this function */
 	if (qse_sio_flush(sio) <= -1) return -1;
-	return (qse_fio_seek (&sio->u.file, 
+	return (qse_fio_seek (&sio->file, 
 		0, QSE_FIO_BEGIN) == (qse_fio_off_t)-1)? -1: 0;
 
 }
@@ -600,8 +595,8 @@ static qse_ssize_t file_input (
 		sio = *(qse_sio_t**)QSE_XTN(tio);
 		QSE_ASSERT (sio != QSE_NULL);
 
-		n = qse_fio_read (&sio->u.file, buf, size);
-		if (n <= -1) sio->errnum = fio_errnum_to_sio_errnum (&sio->u.file);
+		n = qse_fio_read (&sio->file, buf, size);
+		if (n <= -1) sio->errnum = fio_errnum_to_sio_errnum (&sio->file);
 		return n;
 	}
 
@@ -619,61 +614,11 @@ static qse_ssize_t file_output (
 		sio = *(qse_sio_t**)QSE_XTN(tio);
 		QSE_ASSERT (sio != QSE_NULL);
 
-		n = qse_fio_write (&sio->u.file, buf, size);
-		if (n <= -1) sio->errnum = fio_errnum_to_sio_errnum (&sio->u.file);
+		n = qse_fio_write (&sio->file, buf, size);
+		if (n <= -1) sio->errnum = fio_errnum_to_sio_errnum (&sio->file);
 		return n;
 	}
 
 	return 0;
 }
 
-/* ---------------------------------------------------------- */
-
-#if 0
-
-#if defined(_WIN32)
-#	include <winsock2.h>
-#else
-#	include <sys/socket.h>
-#endif
-
-static qse_ssize_t socket_input (
-	qse_tio_t* tio, qse_tio_cmd_t cmd, void* buf, qse_size_t size)
-{
-
-	if (cmd == QSE_TIO_DATA) 
-	{
-		qse_ssize_t n;
-		qse_sio_t* sio;
-
-		sio = *(qse_sio_t**)QSE_XTN(tio);
-		QSE_ASSERT (sio != QSE_NULL);
-
-		n = recv (sio->u.sck, buf, size, 0);
-		if (n <= -1) sio->errnum = syserr_to_errnum (errno);
-		return n;
-	}
-
-	return 0;
-}
-
-static qse_ssize_t socket_output (
-	qse_tio_t* tio, qse_tio_cmd_t cmd, void* buf, qse_size_t size)
-{
-	if (cmd == QSE_TIO_DATA) 
-	{
-		qse_ssize_t n;
-		qse_sio_t* sio;
-
-		sio = *(qse_sio_t**)QSE_XTN(tio);
-		QSE_ASSERT (sio != QSE_NULL);
-
-		n = send (sio->u.sck, buf, size, 0);
-		if (n <= -1) sio->errnum = syserr_to_errnum (errno);
-		return n;
-	}
-
-	return 0;
-}
-
-#endif
diff --git a/qse/lib/sed/err.c b/qse/lib/sed/err.c
index a2278263..79e8015b 100644
--- a/qse/lib/sed/err.c
+++ b/qse/lib/sed/err.c
@@ -21,7 +21,8 @@
 #include "sed.h"
 #include "../cmn/mem.h"
 
-const qse_char_t* qse_sed_dflerrstr (qse_sed_t* sed, qse_sed_errnum_t errnum)
+const qse_char_t* qse_sed_dflerrstr (
+	const qse_sed_t* sed, qse_sed_errnum_t errnum)
 {
 	static const qse_char_t* errstr[] =
  	{
diff --git a/qse/lib/sed/sed.h b/qse/lib/sed/sed.h
index 0e74d5f5..4d116278 100644
--- a/qse/lib/sed/sed.h
+++ b/qse/lib/sed/sed.h
@@ -233,11 +233,10 @@ void qse_sed_fini (
 );
 
 const qse_char_t* qse_sed_dflerrstr (
-	qse_sed_t* sed, 
+	const qse_sed_t* sed, 
 	qse_sed_errnum_t errnum
 );
 
-
 #ifdef USE_REX
 /**
  * The qse_sed_getmaxdepth() gets the maximum processing depth.
diff --git a/qse/samples/net/http01.c b/qse/samples/net/http01.c
index ec81b61e..b4e67069 100644
--- a/qse/samples/net/http01.c
+++ b/qse/samples/net/http01.c
@@ -19,7 +19,12 @@
 #	include <sys/stat.h>
 #	include <sys/socket.h>
 #	include <netinet/in.h>
-#	include <sys/epoll.h>
+#endif
+
+#if defined(HAVE_EPOLL)
+#	if defined(HAVE_SYS_EPOLL_H)
+#		include <sys/epoll.h>
+#	endif
 #endif
 
 #if defined(__linux__)
@@ -332,12 +337,20 @@ static int server_open (qse_httpd_t* httpd, qse_httpd_server_t* server)
 	flag = 1;
 	setsockopt (fd, SOL_SOCKET, SO_REUSEADDR, &flag, QSE_SIZEOF(flag));
 
+#if defined(IP_TRANSPARENT)
+	/* remove the ip routing restriction that a packet can only
+	 * be sent using a local ip address. this option is useful
+	 * if transparency is achieved with TPROXY */
+	flag = 1;
+	setsockopt (fd, SOL_IP, IP_TRANSPARENT, &flag, QSE_SIZEOF(flag));
+#endif
+
 	/* Solaris 8 returns EINVAL if QSE_SIZEOF(addr) is passed in as the 
 	 * address size for AF_INET. */
 	/*if (bind (s, (struct sockaddr*)&addr, QSE_SIZEOF(addr)) <= -1) goto oops_esocket;*/
 	if (bind (fd, (struct sockaddr*)&addr, addrsize) <= -1) 
 	{
-#ifdef IPV6_V6ONLY
+#if defined(IPV6_V6ONLY)
 		if (errno == EADDRINUSE && addr.ss_family == AF_INET6)
 		{
 			int on = 1;
@@ -561,7 +574,11 @@ static void* mux_open (qse_httpd_t* httpd)
 
 	memset (mux, 0, QSE_SIZEOF(*mux));
 
+#if defined(HAVE_EPOLL_CREATE1)
+	mux->fd = epoll_create1 (O_CLOEXEC);
+#else
 	mux->fd = epoll_create (100);
+#endif
 	if (mux->fd <= -1) 
 	{
 		qse_httpd_freemem (httpd, mux);
@@ -569,6 +586,13 @@ static void* mux_open (qse_httpd_t* httpd)
 		return QSE_NULL;
 	}
 
+#if defined(HAVE_EPOLL_CREATE1)
+	/* nothing else to do */
+#else
+	flag = fcntl (mux->fd, F_GETFD);
+	if (flag >= 0) fcntl (mux->fd, F_SETFD, flag | FD_CLOEXEC);
+#endif
+
 	return mux;
 }
 
@@ -1188,6 +1212,7 @@ qse_printf (QSE_T("Entasking chunked CGI...\n"));
 		}
 		else
 		{
+#if 0
 			if (!peek)
 			{
 				/* file or directory */
@@ -1195,6 +1220,15 @@ qse_printf (QSE_T("Entasking chunked CGI...\n"));
 					httpd, client, QSE_NULL, qpath, req);
 				if (task == QSE_NULL) goto oops;
 			}
+#else
+			if (peek)
+			{
+				qse_httpd_discardcontent (httpd, req);
+				task = qse_httpd_entaskfile (
+					httpd, client, QSE_NULL, qpath, req);
+				if (task == QSE_NULL) goto oops;
+			}
+#endif
 		}
 	}
 	else