diff --git a/qse/Makefile.in b/qse/Makefile.in
index 27a2cdfb..9b9cdaa2 100644
--- a/qse/Makefile.in
+++ b/qse/Makefile.in
@@ -57,6 +57,7 @@ DIST_COMMON = $(am__configure_deps) $(srcdir)/Makefile.am \
 	ac/depcomp ac/install-sh ac/ltmain.sh ac/missing
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/aclocal.m4 b/qse/aclocal.m4
index 67fd387d..0aaa0927 100644
--- a/qse/aclocal.m4
+++ b/qse/aclocal.m4
@@ -1027,6 +1027,7 @@ AC_SUBST([am__untar])
 ]) # _AM_PROG_TAR
 
 m4_include([m4/argz.m4])
+m4_include([m4/ax_check_sign.m4])
 m4_include([m4/ax_cxx_namespace.m4])
 m4_include([m4/ax_numval.m4])
 m4_include([m4/ax_pthread.m4])
diff --git a/qse/cmd/Makefile.in b/qse/cmd/Makefile.in
index 070fa133..7e6b12ba 100644
--- a/qse/cmd/Makefile.in
+++ b/qse/cmd/Makefile.in
@@ -54,6 +54,7 @@ subdir = cmd
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/cmd/awk/Makefile.in b/qse/cmd/awk/Makefile.in
index 92dc4041..e2855626 100644
--- a/qse/cmd/awk/Makefile.in
+++ b/qse/cmd/awk/Makefile.in
@@ -64,6 +64,7 @@ subdir = cmd/awk
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/cmd/http/Makefile.am b/qse/cmd/http/Makefile.am
index 967000bd..1071b3f2 100644
--- a/qse/cmd/http/Makefile.am
+++ b/qse/cmd/http/Makefile.am
@@ -8,7 +8,7 @@ AM_CPPFLAGS = \
 qsecfgdir = $(sysconfdir)/qse
 qsecfg_DATA = httpd.conf httpd-mime.conf
 
-bin_PROGRAMS = qsehttpd
+bin_PROGRAMS = qsehttpd qseursd
 
 qsehttpd_SOURCES = httpd.c
 qsehttpd_LDFLAGS = -L../../lib/xli -L../../lib/http -L../../lib/cmn 
@@ -20,4 +20,8 @@ qsehttpd_LDADD += $(UNICOWS_LIBS)
 endif
 endif
 
+qseursd_SOURCES = ursd.c
+qseursd_LDFLAGS = -L../../lib/cmn 
+qseursd_LDADD = -lqsecmn 
+
 EXTRA_DIST = $(qsecfg_DATA)
diff --git a/qse/cmd/http/Makefile.in b/qse/cmd/http/Makefile.in
index c3e7dc0e..1cac6ad2 100644
--- a/qse/cmd/http/Makefile.in
+++ b/qse/cmd/http/Makefile.in
@@ -52,12 +52,13 @@ PRE_UNINSTALL = :
 POST_UNINSTALL = :
 build_triplet = @build@
 host_triplet = @host@
-bin_PROGRAMS = qsehttpd$(EXEEXT)
+bin_PROGRAMS = qsehttpd$(EXEEXT) qseursd$(EXEEXT)
 @WCHAR_TRUE@@WIN32_TRUE@am__append_1 = $(UNICOWS_LIBS)
 subdir = cmd/http
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
@@ -83,6 +84,12 @@ am__v_lt_0 = --silent
 qsehttpd_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
 	$(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
 	$(qsehttpd_LDFLAGS) $(LDFLAGS) -o $@
+am_qseursd_OBJECTS = ursd.$(OBJEXT)
+qseursd_OBJECTS = $(am_qseursd_OBJECTS)
+qseursd_DEPENDENCIES =
+qseursd_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
+	$(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
+	$(qseursd_LDFLAGS) $(LDFLAGS) -o $@
 DEFAULT_INCLUDES = 
 depcomp = $(SHELL) $(top_srcdir)/ac/depcomp
 am__depfiles_maybe = depfiles
@@ -109,8 +116,8 @@ am__v_CCLD_0 = @echo "  CCLD  " $@;
 AM_V_GEN = $(am__v_GEN_@AM_V@)
 am__v_GEN_ = $(am__v_GEN_@AM_DEFAULT_V@)
 am__v_GEN_0 = @echo "  GEN   " $@;
-SOURCES = $(qsehttpd_SOURCES)
-DIST_SOURCES = $(qsehttpd_SOURCES)
+SOURCES = $(qsehttpd_SOURCES) $(qseursd_SOURCES)
+DIST_SOURCES = $(qsehttpd_SOURCES) $(qseursd_SOURCES)
 am__can_run_installinfo = \
   case $$AM_UPDATE_INFO_DIR in \
     n|no|NO) false;; \
@@ -332,6 +339,9 @@ qsecfg_DATA = httpd.conf httpd-mime.conf
 qsehttpd_SOURCES = httpd.c
 qsehttpd_LDFLAGS = -L../../lib/xli -L../../lib/http -L../../lib/cmn 
 qsehttpd_LDADD = -lqsexli -lqsehttp -lqsecmn $(am__append_1)
+qseursd_SOURCES = ursd.c
+qseursd_LDFLAGS = -L../../lib/cmn 
+qseursd_LDADD = -lqsecmn 
 EXTRA_DIST = $(qsecfg_DATA)
 all: all-am
 
@@ -416,6 +426,9 @@ clean-binPROGRAMS:
 qsehttpd$(EXEEXT): $(qsehttpd_OBJECTS) $(qsehttpd_DEPENDENCIES) $(EXTRA_qsehttpd_DEPENDENCIES) 
 	@rm -f qsehttpd$(EXEEXT)
 	$(AM_V_CCLD)$(qsehttpd_LINK) $(qsehttpd_OBJECTS) $(qsehttpd_LDADD) $(LIBS)
+qseursd$(EXEEXT): $(qseursd_OBJECTS) $(qseursd_DEPENDENCIES) $(EXTRA_qseursd_DEPENDENCIES) 
+	@rm -f qseursd$(EXEEXT)
+	$(AM_V_CCLD)$(qseursd_LINK) $(qseursd_OBJECTS) $(qseursd_LDADD) $(LIBS)
 
 mostlyclean-compile:
 	-rm -f *.$(OBJEXT)
@@ -424,6 +437,7 @@ distclean-compile:
 	-rm -f *.tab.c
 
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/httpd.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ursd.Po@am__quote@
 
 .c.o:
 @am__fastdepCC_TRUE@	$(AM_V_CC)$(COMPILE) -MT $@ -MD -MP -MF $(DEPDIR)/$*.Tpo -c -o $@ $<
diff --git a/qse/cmd/http/httpd.c b/qse/cmd/http/httpd.c
index 1f9f3033..5ce9ef12 100644
--- a/qse/cmd/http/httpd.c
+++ b/qse/cmd/http/httpd.c
@@ -188,7 +188,7 @@ struct loccfg_t
 		unsigned int allow_http: 1;
 		unsigned int allow_connect: 1;
 		unsigned int dns_enabled: 1;
-		unsigned int urs_enabled: 1;
+		unsigned int urs_enabled: 2;
 		qse_nwad_t dns_nwad; /* TODO: multiple dns */
 		qse_nwad_t urs_nwad; /* TODO: multiple urs */
 		int dns_timeout;
@@ -1467,8 +1467,6 @@ static int load_loccfg_proxy (qse_httpd_t* httpd, qse_xli_t* xli, qse_xli_list_t
 	if (pair) cfg->proxy.dns_retries = get_integer ((qse_xli_str_t*)pair->val);
 	else cfg->proxy.dns_retries = -1;
 
-
-
 	pair = QSE_NULL;
 	if (proxy) pair = qse_xli_findpair (xli, proxy, QSE_T("urs-enabled"));
 	if (!pair && default_proxy) pair = qse_xli_findpair (xli, default_proxy, QSE_T("urs-enabled"));
diff --git a/qse/cmd/http/httpd.conf b/qse/cmd/http/httpd.conf
index ced293aa..f7a99511 100644
--- a/qse/cmd/http/httpd.conf
+++ b/qse/cmd/http/httpd.conf
@@ -138,7 +138,7 @@ server-default {
 		#dns-timeout = 3
 		#dns-retries = 2
 
-		#urs-enabled = yes;
+		#urs-enabled = yes; # no, yes,
 		#urs-server = "127.0.0.1:97";
 		#urs-timeout = 1;
 		#urs-retries = 4;
diff --git a/qse/cmd/sed/Makefile.in b/qse/cmd/sed/Makefile.in
index 8e68f613..09625176 100644
--- a/qse/cmd/sed/Makefile.in
+++ b/qse/cmd/sed/Makefile.in
@@ -57,6 +57,7 @@ subdir = cmd/sed
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/cmd/xli/Makefile.in b/qse/cmd/xli/Makefile.in
index 2ca68d3c..d9da0492 100644
--- a/qse/cmd/xli/Makefile.in
+++ b/qse/cmd/xli/Makefile.in
@@ -57,6 +57,7 @@ subdir = cmd/xli
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/configure b/qse/configure
index f6bad06a..2ae1f073 100755
--- a/qse/configure
+++ b/qse/configure
@@ -17451,7 +17451,7 @@ fi
 
 done
 
-for ac_header in sys/sysctl.h sys/socket.h sys/sockio.h ifaddrs.h linux/netfilter_ipv4.h
+for ac_header in sys/sysctl.h sys/socket.h sys/sockio.h ifaddrs.h linux/netfilter_ipv4.h netinet/sctp.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"
@@ -19829,7 +19829,7 @@ _ACEOF
 
 if test "${platform_win32}" == "yes"
 then
-# The cast to long int works around a bug in the HP C Compiler
+	# The cast to long int works around a bug in the HP C Compiler
 # version HP92453-01 B.11.11.23709.GP, which incorrectly rejects
 # declarations like `int a3[[(sizeof (unsigned char)) >= 0]];'.
 # This bug is HP SR number 8606223364.
@@ -19839,8 +19839,8 @@ if ${ac_cv_sizeof_struct_sockaddr_in+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if ac_fn_c_compute_int "$LINENO" "(long int) (sizeof (struct sockaddr_in))" "ac_cv_sizeof_struct_sockaddr_in"        "
-	#include <winsock2.h>
-	#include <ws2tcpip.h>
+		#include <winsock2.h>
+		#include <ws2tcpip.h>
 "; then :
 
 else
@@ -19865,7 +19865,7 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
-# The cast to long int works around a bug in the HP C Compiler
+	# The cast to long int works around a bug in the HP C Compiler
 # version HP92453-01 B.11.11.23709.GP, which incorrectly rejects
 # declarations like `int a3[[(sizeof (unsigned char)) >= 0]];'.
 # This bug is HP SR number 8606223364.
@@ -19875,8 +19875,8 @@ if ${ac_cv_sizeof_struct_sockaddr_in6+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if ac_fn_c_compute_int "$LINENO" "(long int) (sizeof (struct sockaddr_in6))" "ac_cv_sizeof_struct_sockaddr_in6"        "
-	#include <winsock2.h>
-	#include <ws2tcpip.h>
+		#include <winsock2.h>
+		#include <ws2tcpip.h>
 "; then :
 
 else
@@ -19901,8 +19901,87 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
+	# The cast to long int works around a bug in the HP C Compiler
+# version HP92453-01 B.11.11.23709.GP, which incorrectly rejects
+# declarations like `int a3[[(sizeof (unsigned char)) >= 0]];'.
+# This bug is HP SR number 8606223364.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking size of socklen_t" >&5
+$as_echo_n "checking size of socklen_t... " >&6; }
+if ${ac_cv_sizeof_socklen_t+:} false; then :
+  $as_echo_n "(cached) " >&6
 else
-# The cast to long int works around a bug in the HP C Compiler
+  if ac_fn_c_compute_int "$LINENO" "(long int) (sizeof (socklen_t))" "ac_cv_sizeof_socklen_t"        "
+		#include <winsock2.h>
+		#include <ws2tcpip.h>
+"; then :
+
+else
+  if test "$ac_cv_type_socklen_t" = yes; then
+     { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error 77 "cannot compute sizeof (socklen_t)
+See \`config.log' for more details" "$LINENO" 5; }
+   else
+     ac_cv_sizeof_socklen_t=0
+   fi
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_sizeof_socklen_t" >&5
+$as_echo "$ac_cv_sizeof_socklen_t" >&6; }
+
+
+
+cat >>confdefs.h <<_ACEOF
+#define SIZEOF_SOCKLEN_T $ac_cv_sizeof_socklen_t
+_ACEOF
+
+
+
+	if test ${ac_cv_sizeof_socklen_t} -gt 0
+	then
+
+ typename=`echo socklen_t | sed "s/[^a-zA-Z0-9_]/_/g"`
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether socklen_t is signed" >&5
+$as_echo_n "checking whether socklen_t is signed... " >&6; }
+if eval \${ax_cv_decl_${typename}_signed+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <winsock2.h>
+			 #include <ws2tcpip.h>
+int
+main ()
+{
+ int foo [ 1 - 2 * !(((socklen_t) -1) < 0) ]
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+   eval "ax_cv_decl_${typename}_signed=\"yes\""
+else
+   eval "ax_cv_decl_${typename}_signed=\"no\""
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+eval ac_res=\$ax_cv_decl_${typename}_signed
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+ symbolname=`echo socklen_t | sed "s/[^a-zA-Z0-9_]/_/g" | tr "a-z" "A-Z"`
+ if eval "test \"\${ax_cv_decl_${typename}_signed}\" = \"yes\""; then
+
+$as_echo "#define QSE_SOCKLEN_T_IS_SIGNED 1" >>confdefs.h
+
+ elif eval "test \"\${ax_cv_decl_${typename}_signed}\" = \"no\""; then
+    $as_echo_n ""
+ fi
+
+	fi
+else
+	# The cast to long int works around a bug in the HP C Compiler
 # version HP92453-01 B.11.11.23709.GP, which incorrectly rejects
 # declarations like `int a3[[(sizeof (unsigned char)) >= 0]];'.
 # This bug is HP SR number 8606223364.
@@ -19912,8 +19991,8 @@ if ${ac_cv_sizeof_struct_sockaddr_in+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if ac_fn_c_compute_int "$LINENO" "(long int) (sizeof (struct sockaddr_in))" "ac_cv_sizeof_struct_sockaddr_in"        "
-	#include <sys/socket.h>
-	#include <netinet/in.h>
+		#include <sys/socket.h>
+		#include <netinet/in.h>
 "; then :
 
 else
@@ -19938,7 +20017,7 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
-# The cast to long int works around a bug in the HP C Compiler
+	# The cast to long int works around a bug in the HP C Compiler
 # version HP92453-01 B.11.11.23709.GP, which incorrectly rejects
 # declarations like `int a3[[(sizeof (unsigned char)) >= 0]];'.
 # This bug is HP SR number 8606223364.
@@ -19948,8 +20027,8 @@ if ${ac_cv_sizeof_struct_sockaddr_in6+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if ac_fn_c_compute_int "$LINENO" "(long int) (sizeof (struct sockaddr_in6))" "ac_cv_sizeof_struct_sockaddr_in6"        "
-	#include <sys/socket.h>
-	#include <netinet/in.h>
+		#include <sys/socket.h>
+		#include <netinet/in.h>
 "; then :
 
 else
@@ -19974,8 +20053,87 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
+	# The cast to long int works around a bug in the HP C Compiler
+# version HP92453-01 B.11.11.23709.GP, which incorrectly rejects
+# declarations like `int a3[[(sizeof (unsigned char)) >= 0]];'.
+# This bug is HP SR number 8606223364.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking size of socklen_t" >&5
+$as_echo_n "checking size of socklen_t... " >&6; }
+if ${ac_cv_sizeof_socklen_t+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if ac_fn_c_compute_int "$LINENO" "(long int) (sizeof (socklen_t))" "ac_cv_sizeof_socklen_t"        "
+		#include <sys/socket.h>
+		#include <netinet/in.h>
+"; then :
+
+else
+  if test "$ac_cv_type_socklen_t" = yes; then
+     { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error 77 "cannot compute sizeof (socklen_t)
+See \`config.log' for more details" "$LINENO" 5; }
+   else
+     ac_cv_sizeof_socklen_t=0
+   fi
 fi
 
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_sizeof_socklen_t" >&5
+$as_echo "$ac_cv_sizeof_socklen_t" >&6; }
+
+
+
+cat >>confdefs.h <<_ACEOF
+#define SIZEOF_SOCKLEN_T $ac_cv_sizeof_socklen_t
+_ACEOF
+
+
+
+	if test ${ac_cv_sizeof_socklen_t} -gt 0
+	then
+
+ typename=`echo socklen_t | sed "s/[^a-zA-Z0-9_]/_/g"`
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether socklen_t is signed" >&5
+$as_echo_n "checking whether socklen_t is signed... " >&6; }
+if eval \${ax_cv_decl_${typename}_signed+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/socket.h>
+int
+main ()
+{
+ int foo [ 1 - 2 * !(((socklen_t) -1) < 0) ]
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+   eval "ax_cv_decl_${typename}_signed=\"yes\""
+else
+   eval "ax_cv_decl_${typename}_signed=\"no\""
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+eval ac_res=\$ax_cv_decl_${typename}_signed
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+ symbolname=`echo socklen_t | sed "s/[^a-zA-Z0-9_]/_/g" | tr "a-z" "A-Z"`
+ if eval "test \"\${ax_cv_decl_${typename}_signed}\" = \"yes\""; then
+
+$as_echo "#define QSE_SOCKLEN_T_IS_SIGNED 1" >>confdefs.h
+
+ elif eval "test \"\${ax_cv_decl_${typename}_signed}\" = \"no\""; then
+    $as_echo_n ""
+ fi
+
+	fi
+fi
+
+
 if test ${ac_cv_sizeof___int128_t} -gt 0
 then
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking __int128_t with %" >&5
@@ -20170,6 +20328,7 @@ fi
 
 
 
+
 cat >>confdefs.h <<_ACEOF
 #define QSE_SIZEOF_CHAR ${ac_cv_sizeof_char}
 _ACEOF
@@ -20288,6 +20447,12 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
+cat >>confdefs.h <<_ACEOF
+#define QSE_SIZEOF_SOCKLEN_T ${ac_cv_sizeof_socklen_t}
+_ACEOF
+
+
+
 qse_package_version_major="`echo ${PACKAGE_VERSION} | cut -d. -f1`"
 qse_package_version_minor="`echo ${PACKAGE_VERSION} | cut -d. -f2`"
 qse_package_version_patch="`echo ${PACKAGE_VERSION} | cut -d. -f3`"
@@ -21152,34 +21317,6 @@ $as_echo "#define QSE_ENABLE_SED_TRACER /**/" >>confdefs.h
 
 fi
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for socklen_t in sys/socket.h" >&5
-$as_echo_n "checking for socklen_t in sys/socket.h... " >&6; }
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#define _POSIX_PII_SOCKET
-#include <sys/types.h>
-#include <sys/socket.h>
-int
-main ()
-{
-socklen_t x = 5;
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
-
-$as_echo "#define HAVE_SOCKLEN_T 1" >>confdefs.h
-
-	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-$as_echo "yes" >&6; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-
 if test "${enable_shared}" = "no" -a "${enable_static}" = "yes"
 then
 
diff --git a/qse/configure.ac b/qse/configure.ac
index b1b451e9..732e38be 100644
--- a/qse/configure.ac
+++ b/qse/configure.ac
@@ -123,7 +123,7 @@ AC_CHECK_HEADERS([stddef.h wchar.h wctype.h errno.h signal.h fcntl.h dirent.h])
 AC_CHECK_HEADERS([time.h sys/time.h utime.h spawn.h execinfo.h ucontext.h])
 AC_CHECK_HEADERS([sys/resource.h sys/wait.h sys/syscall.h sys/ioctl.h])
 AC_CHECK_HEADERS([sys/sendfile.h sys/epoll.h sys/event.h])
-AC_CHECK_HEADERS([sys/sysctl.h sys/socket.h sys/sockio.h ifaddrs.h linux/netfilter_ipv4.h])
+AC_CHECK_HEADERS([sys/sysctl.h sys/socket.h sys/sockio.h ifaddrs.h linux/netfilter_ipv4.h netinet/sctp.h])
 AC_CHECK_HEADERS([net/if.h net/if_dl.h], [], [], [
 	#include <sys/types.h>
 	#include <sys/socket.h>])
@@ -132,8 +132,8 @@ AC_CHECK_HEADERS([quadmath.h crt_externs.h sys/prctl.h uci.h])
 
 dnl check data types
 AC_CHECK_TYPE([wchar_t], 
-	[AC_DEFINE([HAVE_WCHAR_T_IN_STDDEF_H],
-	           [],[wchar_t is available in stddef.h])],
+	[ AC_DEFINE([HAVE_WCHAR_T_IN_STDDEF_H],
+	           [],[wchar_t is available in stddef.h]) ],
 	[],
 	[#include <stddef.h>])
 
@@ -368,21 +368,45 @@ AX_CHECK_NUMVALOF(MB_LEN_MAX,[32],[#include <limits.h>])
 
 if test "${platform_win32}" == "yes"
 then
-AC_CHECK_SIZEOF(struct sockaddr_in,,[
-	#include <winsock2.h>
-	#include <ws2tcpip.h>])
-AC_CHECK_SIZEOF(struct sockaddr_in6,, [
-	#include <winsock2.h>
-	#include <ws2tcpip.h>])
+	AC_CHECK_SIZEOF(struct sockaddr_in,,[
+		#include <winsock2.h>
+		#include <ws2tcpip.h>])
+	AC_CHECK_SIZEOF(struct sockaddr_in6,,[
+		#include <winsock2.h>
+		#include <ws2tcpip.h>])
+	AC_CHECK_SIZEOF(socklen_t,, [
+		#include <winsock2.h>
+		#include <ws2tcpip.h>])
+
+	if test ${ac_cv_sizeof_socklen_t} -gt 0
+	then
+		AX_CHECK_SIGN([socklen_t],
+			[ AC_DEFINE(QSE_SOCKLEN_T_IS_SIGNED, 1, [Define if socklen_t is signed]) ],
+			[ AS_ECHO_N("") ],
+			[#include <winsock2.h>
+			 #include <ws2tcpip.h>])
+	fi
 else
-AC_CHECK_SIZEOF(struct sockaddr_in,,[
-	#include <sys/socket.h>
-	#include <netinet/in.h>])
-AC_CHECK_SIZEOF(struct sockaddr_in6,, [
-	#include <sys/socket.h>
-	#include <netinet/in.h>])
+	AC_CHECK_SIZEOF(struct sockaddr_in,,[
+		#include <sys/socket.h>
+		#include <netinet/in.h>])
+	AC_CHECK_SIZEOF(struct sockaddr_in6,,[
+		#include <sys/socket.h>
+		#include <netinet/in.h>])
+	AC_CHECK_SIZEOF(socklen_t,, [
+		#include <sys/socket.h>
+		#include <netinet/in.h>])
+
+	if test ${ac_cv_sizeof_socklen_t} -gt 0
+	then
+		AX_CHECK_SIGN([socklen_t],
+			[ AC_DEFINE(QSE_SOCKLEN_T_IS_SIGNED, 1, [Define if socklen_t is signed]) ],
+			[ AS_ECHO_N("") ],
+			[#include <sys/socket.h>])
+	fi
 fi
 
+
 dnl gcc 3.4.3 on opensolaris x86 gave this warning without -msse or 
 dnl something similar.
 dnl    SSE vector argument without SSE enabled changes the ABI
@@ -483,6 +507,7 @@ then
 fi
 AC_SUBST(QUADMATH_LIBS)
 
+
 AC_DEFINE_UNQUOTED(QSE_SIZEOF_CHAR, ${ac_cv_sizeof_char}, [sizeof(char)])
 AC_DEFINE_UNQUOTED(QSE_SIZEOF_SHORT, ${ac_cv_sizeof_short}, [sizeof(short)])
 AC_DEFINE_UNQUOTED(QSE_SIZEOF_INT, ${ac_cv_sizeof_int}, [sizeof(int)])
@@ -509,6 +534,8 @@ AC_DEFINE_UNQUOTED(QSE_MBLEN_MAX, ${ax_cv_numvalof_MB_LEN_MAX}, [MB_LEN_MAX])
 
 AC_DEFINE_UNQUOTED(QSE_SIZEOF_STRUCT_SOCKADDR_IN, ${ac_cv_sizeof_struct_sockaddr_in}, [sizeof(struct sockaddr_in)])
 AC_DEFINE_UNQUOTED(QSE_SIZEOF_STRUCT_SOCKADDR_IN6, ${ac_cv_sizeof_struct_sockaddr_in6}, [sizeof(struct sockaddr_in6)])
+AC_DEFINE_UNQUOTED(QSE_SIZEOF_SOCKLEN_T, ${ac_cv_sizeof_socklen_t}, [sizeof(socklen_t)])
+
 
 qse_package_version_major="`echo ${PACKAGE_VERSION} | cut -d. -f1`"
 qse_package_version_minor="`echo ${PACKAGE_VERSION} | cut -d. -f2`"
@@ -641,15 +668,6 @@ then
 	AC_DEFINE([QSE_ENABLE_SED_TRACER],[],[enable qse_sed_setexectracer()])
 fi
 
-AC_MSG_CHECKING([for socklen_t in sys/socket.h])
-AC_TRY_COMPILE([#define _POSIX_PII_SOCKET
-#include <sys/types.h>
-#include <sys/socket.h>], [socklen_t x = 5;],
-	[AC_DEFINE(HAVE_SOCKLEN_T, 1, [Define it socklen_t typedef is in sys/socket.h.])
-	AC_MSG_RESULT(yes)],
-	[AC_MSG_RESULT(no)]
-)
-
 if test "${enable_shared}" = "no" -a "${enable_static}" = "yes"
 then
 	AC_DEFINE([QSE_ENABLE_STATIC_MODULE],[],[link modules statically into the main library])
diff --git a/qse/doc/Makefile.in b/qse/doc/Makefile.in
index 35db36f1..975201aa 100644
--- a/qse/doc/Makefile.in
+++ b/qse/doc/Makefile.in
@@ -55,6 +55,7 @@ DIST_COMMON = $(srcdir)/Doxyfile.in $(srcdir)/Makefile.am \
 	$(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/include/Makefile.in b/qse/include/Makefile.in
index 539a4a42..2cbe1b8d 100644
--- a/qse/include/Makefile.in
+++ b/qse/include/Makefile.in
@@ -54,6 +54,7 @@ subdir = include
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/include/qse/Makefile.in b/qse/include/qse/Makefile.in
index 9f10ad35..a332f11e 100644
--- a/qse/include/qse/Makefile.in
+++ b/qse/include/qse/Makefile.in
@@ -56,6 +56,7 @@ DIST_COMMON = $(am__pkginclude_HEADERS_DIST) $(srcdir)/Makefile.am \
 	$(srcdir)/Makefile.in $(srcdir)/config.h.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/include/qse/awk/Makefile.in b/qse/include/qse/awk/Makefile.in
index f7b53d62..3e346828 100644
--- a/qse/include/qse/awk/Makefile.in
+++ b/qse/include/qse/awk/Makefile.in
@@ -56,6 +56,7 @@ DIST_COMMON = $(am__pkginclude_HEADERS_DIST) $(srcdir)/Makefile.am \
 	$(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/include/qse/cmn/Makefile.am b/qse/include/qse/cmn/Makefile.am
index 11243cac..5b890f32 100644
--- a/qse/include/qse/cmn/Makefile.am
+++ b/qse/include/qse/cmn/Makefile.am
@@ -34,6 +34,7 @@ pkginclude_HEADERS = \
 	pma.h \
 	rbt.h \
 	rex.h \
+	sck.h \
 	sio.h \
 	sll.h \
 	slmb.h \
diff --git a/qse/include/qse/cmn/Makefile.in b/qse/include/qse/cmn/Makefile.in
index 3808010b..307f916b 100644
--- a/qse/include/qse/cmn/Makefile.in
+++ b/qse/include/qse/cmn/Makefile.in
@@ -56,6 +56,7 @@ DIST_COMMON = $(am__pkginclude_HEADERS_DIST) $(srcdir)/Makefile.am \
 	$(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
@@ -84,8 +85,8 @@ am__can_run_installinfo = \
 am__pkginclude_HEADERS_DIST = alg.h chr.h cp949.h cp950.h dir.h dll.h \
 	env.h fio.h fma.h fmt.h fs.h gdl.h glob.h htb.h hton.h ipad.h \
 	lda.h main.h map.h mb8.h mbwc.h mem.h mux.h nwad.h nwif.h \
-	nwio.h oht.h opt.h path.h pio.h pma.h rbt.h rex.h sio.h sll.h \
-	slmb.h str.h task.h time.h tio.h tmr.h tre.h uni.h uri.h \
+	nwio.h oht.h opt.h path.h pio.h pma.h rbt.h rex.h sck.h sio.h \
+	sll.h slmb.h str.h task.h time.h tio.h tmr.h tre.h uni.h uri.h \
 	utf8.h xma.h Mmgr.hpp StdMmgr.hpp Mmged.hpp
 am__vpath_adj_setup = srcdirstrip=`echo "$(srcdir)" | sed 's|.|.|g'`;
 am__vpath_adj = case $$p in \
@@ -298,9 +299,9 @@ top_srcdir = @top_srcdir@
 pkginclude_HEADERS = alg.h chr.h cp949.h cp950.h dir.h dll.h env.h \
 	fio.h fma.h fmt.h fs.h gdl.h glob.h htb.h hton.h ipad.h lda.h \
 	main.h map.h mb8.h mbwc.h mem.h mux.h nwad.h nwif.h nwio.h \
-	oht.h opt.h path.h pio.h pma.h rbt.h rex.h sio.h sll.h slmb.h \
-	str.h task.h time.h tio.h tmr.h tre.h uni.h uri.h utf8.h xma.h \
-	$(am__append_1)
+	oht.h opt.h path.h pio.h pma.h rbt.h rex.h sck.h sio.h sll.h \
+	slmb.h str.h task.h time.h tio.h tmr.h tre.h uni.h uri.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
index 0a174119..d3b8f223 100644
--- a/qse/include/qse/cmn/nwio.h
+++ b/qse/include/qse/cmn/nwio.h
@@ -30,6 +30,7 @@
 #include <qse/cmn/tio.h>
 #include <qse/cmn/nwad.h>
 #include <qse/cmn/time.h>
+#include <qse/cmn/sck.h>
 
 enum qse_nwio_flag_t
 {
@@ -82,16 +83,7 @@ struct qse_nwio_tmout_t
 
 typedef struct qse_nwio_tmout_t qse_nwio_tmout_t;
 
-#if defined(_WIN32)
-	typedef qse_uintptr_t qse_nwio_hnd_t;
-#elif defined(__OS2__)
-     typedef int qse_nwio_hnd_t;
-#elif defined(__DOS__)
-     typedef int qse_nwio_hnd_t;
-#else
-     typedef int qse_nwio_hnd_t;
-#endif
-
+typedef qse_sck_hnd_t qse_nwio_hnd_t;
 typedef struct qse_nwio_t qse_nwio_t;
 
 /**
@@ -102,7 +94,7 @@ struct qse_nwio_t
 	qse_mmgr_t*        mmgr;
 	int                flags;
 	qse_nwio_errnum_t  errnum;
-	qse_nwio_tmout_t tmout;
+	qse_nwio_tmout_t   tmout;
 	qse_nwio_hnd_t     handle;
 	qse_tio_t*         tio;
 	int                status;
diff --git a/qse/include/qse/cmn/sck.h b/qse/include/qse/cmn/sck.h
new file mode 100644
index 00000000..8cf35950
--- /dev/null
+++ b/qse/include/qse/cmn/sck.h
@@ -0,0 +1,76 @@
+/*
+ * $Id$
+ *
+    Copyright 2006-2014 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_SCK_H_
+#define _QSE_CMN_SCK_H_
+
+
+#include <qse/types.h>
+#include <qse/macros.h>
+
+#if defined(_WIN32)
+	typedef qse_uintptr_t qse_sck_hnd_t;
+#	define QSE_INVALID_SCKHND (~(qse_sck_hnd_t)0)
+#elif defined(__OS2__)
+	typedef int qse_sck_hnd_t;
+#	define QSE_INVALID_SCKHND -1
+#elif defined(__DOS__)
+	typedef int qse_sck_hnd_t;
+#	define QSE_INVALID_SCKHND -1
+#else
+	typedef int qse_sck_hnd_t;
+#	define QSE_INVALID_SCKHND -1
+#endif
+
+#if (QSE_SIZEOF_SOCKLEN_T == QSE_SIZEOF_INT)
+	#if defined(QSE_SOCKLEN_T_IS_SIGNED)
+		typedef int qse_sck_len_t;
+	#else
+		typedef unsigned int qse_sck_len_t;
+	#endif
+#elif (QSE_SIZEOF_SOCKLEN_T == QSE_SIZEOF_LONG)
+	#if defined(QSE_SOCKLEN_T_IS_SIGNED)
+		typedef long qse_sck_len_t;
+	#else
+		typedef unsigned long qse_sck_len_t;
+	#endif
+#else
+	typedef int qse_sck_len_t;
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+QSE_EXPORT int qse_isvalidsckhnd (
+	qse_sck_hnd_t handle
+);
+
+QSE_EXPORT void qse_closesckhnd (
+	qse_sck_hnd_t handle
+);
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif
+	
diff --git a/qse/include/qse/conf-dos.h b/qse/include/qse/conf-dos.h
index 7cee707a..9dd10cd1 100644
--- a/qse/include/qse/conf-dos.h
+++ b/qse/include/qse/conf-dos.h
@@ -61,6 +61,7 @@
 	/* these two have only to be large enough */
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN 32
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN6 64
+#	define QSE_SIZEOF_SOCKLEN_T 4
 
 #	if !defined(QSE_CHAR_IS_WCHAR) && !defined(QSE_CHAR_IS_MCHAR)
 #		define QSE_CHAR_IS_WCHAR      1
@@ -100,6 +101,7 @@
 	/* these two have only to be large enough */
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN 32
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN6 64
+#	define QSE_SIZEOF_SOCKLEN_T 4
 
 #	if !defined(QSE_CHAR_IS_WCHAR) && !defined(QSE_CHAR_IS_MCHAR)
 #		define QSE_CHAR_IS_WCHAR      1
diff --git a/qse/include/qse/conf-mac.h b/qse/include/qse/conf-mac.h
index e42f089f..935fb54c 100644
--- a/qse/include/qse/conf-mac.h
+++ b/qse/include/qse/conf-mac.h
@@ -57,6 +57,7 @@
 	/* these two have only to be large enough */
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN 32
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN6 64
+#	define QSE_SIZEOF_SOCKLEN_T 4
 
 #	if !defined(QSE_CHAR_IS_WCHAR) && !defined(QSE_CHAR_IS_MCHAR)
 #		define QSE_CHAR_IS_WCHAR      1
diff --git a/qse/include/qse/conf-msw.h b/qse/include/qse/conf-msw.h
index 508b1d5a..04e6193a 100644
--- a/qse/include/qse/conf-msw.h
+++ b/qse/include/qse/conf-msw.h
@@ -80,6 +80,7 @@ _M_X64 x64 platform
 	/* these two have only to be large enough */
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN 32
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN6 64
+#	define QSE_SIZEOF_SOCKLEN_T 4
 
 #	if !defined(QSE_CHAR_IS_WCHAR) && !defined(QSE_CHAR_IS_MCHAR)
 #		define QSE_CHAR_IS_WCHAR      1
@@ -164,6 +165,7 @@ _M_X64 x64 platform
 	/* these two have only to be large enough */
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN 32
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN6 64
+#	define QSE_SIZEOF_SOCKLEN_T 4
 
 #	if !defined(QSE_CHAR_IS_WCHAR) && !defined(QSE_CHAR_IS_MCHAR)
 #		define QSE_CHAR_IS_WCHAR      1
@@ -202,6 +204,7 @@ _M_X64 x64 platform
 	/* these two have only to be large enough */
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN 32
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN6 64
+#	define QSE_SIZEOF_SOCKLEN_T 4
 
 #	if !defined(QSE_CHAR_IS_WCHAR) && !defined(QSE_CHAR_IS_MCHAR)
 #		define QSE_CHAR_IS_WCHAR      1
diff --git a/qse/include/qse/conf-os2.h b/qse/include/qse/conf-os2.h
index 0aae3e33..73bee626 100644
--- a/qse/include/qse/conf-os2.h
+++ b/qse/include/qse/conf-os2.h
@@ -64,6 +64,7 @@
 	/* these two have only to be large enough */
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN 32
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN6 64
+#	define QSE_SIZEOF_SOCKLEN_T 4
 
 #	if !defined(QSE_CHAR_IS_WCHAR) && !defined(QSE_CHAR_IS_MCHAR)
 #		define QSE_CHAR_IS_WCHAR 1
@@ -101,6 +102,7 @@
 
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN 32
 #	define QSE_SIZEOF_STRUCT_SOCKADDR_IN6 64
+#	define QSE_SIZEOF_SOCKLEN_T 4
 
 #	if !defined(QSE_CHAR_IS_WCHAR) && !defined(QSE_CHAR_IS_MCHAR)
 #		define QSE_CHAR_IS_WCHAR 1
diff --git a/qse/include/qse/conf-vms.h b/qse/include/qse/conf-vms.h
index b7cd7ad3..d0674ac2 100644
--- a/qse/include/qse/conf-vms.h
+++ b/qse/include/qse/conf-vms.h
@@ -118,6 +118,7 @@
 /* these two have only to be large enough */
 #define QSE_SIZEOF_STRUCT_SOCKADDR_IN 32
 #define QSE_SIZEOF_STRUCT_SOCKADDR_IN6 64
+#define QSE_SIZEOF_SOCKLEN_T 4
 
 #if !defined(QSE_CHAR_IS_WCHAR) && !defined(QSE_CHAR_IS_MCHAR)
 #	define QSE_CHAR_IS_WCHAR      1
diff --git a/qse/include/qse/config.h.in b/qse/include/qse/config.h.in
index c499069b..3e7fe701 100644
--- a/qse/include/qse/config.h.in
+++ b/qse/include/qse/config.h.in
@@ -350,6 +350,9 @@
 /* Define to 1 if you have the <ndir.h> header file, and it defines `DIR'. */
 #undef HAVE_NDIR_H
 
+/* Define to 1 if you have the <netinet/sctp.h> header file. */
+#undef HAVE_NETINET_SCTP_H
+
 /* Define to 1 if you have the <net/if_dl.h> header file. */
 #undef HAVE_NET_IF_DL_H
 
@@ -461,9 +464,6 @@
 /* Define to 1 if you have the `sinq' function. */
 #undef HAVE_SINQ
 
-/* Define it socklen_t typedef is in sys/socket.h. */
-#undef HAVE_SOCKLEN_T
-
 /* Define to 1 if you have the <spawn.h> header file. */
 #undef HAVE_SPAWN_H
 
@@ -853,6 +853,9 @@
 /* sizeof(short) */
 #undef QSE_SIZEOF_SHORT
 
+/* sizeof(socklen_t) */
+#undef QSE_SIZEOF_SOCKLEN_T
+
 /* sizeof(struct sockaddr_in) */
 #undef QSE_SIZEOF_STRUCT_SOCKADDR_IN
 
@@ -886,6 +889,9 @@
 /* sizeof(__int8) */
 #undef QSE_SIZEOF___INT8
 
+/* Define if socklen_t is signed */
+#undef QSE_SOCKLEN_T_IS_SIGNED
+
 /* use qse_fltmax_t for floating-point numbers in AWK */
 #undef QSE_USE_AWK_FLTMAX
 
@@ -928,6 +934,9 @@
 /* The size of `short', as computed by sizeof. */
 #undef SIZEOF_SHORT
 
+/* The size of `socklen_t', as computed by sizeof. */
+#undef SIZEOF_SOCKLEN_T
+
 /* The size of `struct sockaddr_in', as computed by sizeof. */
 #undef SIZEOF_STRUCT_SOCKADDR_IN
 
diff --git a/qse/include/qse/http/Makefile.in b/qse/include/qse/http/Makefile.in
index 02560613..ecf9ca82 100644
--- a/qse/include/qse/http/Makefile.in
+++ b/qse/include/qse/http/Makefile.in
@@ -55,6 +55,7 @@ DIST_COMMON = $(pkginclude_HEADERS) $(srcdir)/Makefile.am \
 	$(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/include/qse/http/httpd.h b/qse/include/qse/http/httpd.h
index fa7067e4..f07a6994 100644
--- a/qse/include/qse/http/httpd.h
+++ b/qse/include/qse/http/httpd.h
@@ -83,7 +83,7 @@ enum qse_httpd_trait_t
 	QSE_HTTPD_PROXYNOVIA   = (1 << 4),
 	QSE_HTTPD_LOGACT       = (1 << 5),
 	QSE_HTTPD_DNSNOA       = (1 << 6),
-	QSE_HTTPD_DNSNOAAAA    = (1 << 7),
+	QSE_HTTPD_DNSNOAAAA    = (1 << 7)
 };
 typedef enum qse_httpd_trait_t qse_httpd_trait_t;
 
@@ -131,9 +131,9 @@ typedef struct qse_httpd_natr_t qse_httpd_natr_t;
 
 struct qse_httpd_natr_t
 {
-	qse_nwad_t nwad;
+	qse_nwad_t  nwad;
 	qse_ntime_t tmout;
-	int retries;
+	int         retries;
 };
 
 typedef void (*qse_httpd_resol_t) (
@@ -584,13 +584,13 @@ struct qse_httpd_rsrc_cgi_t
 
 enum qse_httpd_rsrc_proxy_flag_t
 {
-	QSE_HTTPD_RSRC_PROXY_RAW         = (1 << 0), /* raw proxying. set this for CONNECT */
-	QSE_HTTPD_RSRC_PROXY_TRANSPARENT = (1 << 1),
-	QSE_HTTPD_RSRC_PROXY_DST_STR     = (1 << 2), /* destination is an unresovled string pointed to by dst.str */
-	QSE_HTTPD_RSRC_PROXY_ENABLE_DNS  = (1 << 3), /* dns service enabled */
-	QSE_HTTPD_RSRC_PROXY_ENABLE_URS  = (1 << 4), /* url rewriting enabled */
-	QSE_HTTPD_RSRC_PROXY_DNS_SERVER  = (1 << 5), /* dns address specified */
-	QSE_HTTPD_RSRC_PROXY_URS_SERVER  = (1 << 6)  /* urs address specified */
+	QSE_HTTPD_RSRC_PROXY_RAW             = (1 << 0), /* raw proxying. set this for CONNECT */
+	QSE_HTTPD_RSRC_PROXY_TRANSPARENT     = (1 << 1),
+	QSE_HTTPD_RSRC_PROXY_DST_STR         = (1 << 2), /* destination is an unresovled string pointed to by dst.str */
+	QSE_HTTPD_RSRC_PROXY_ENABLE_DNS      = (1 << 3), /* dns service enabled (udp) */
+	QSE_HTTPD_RSRC_PROXY_ENABLE_URS      = (1 << 4), /* url rewriting enabled (udp) */
+	QSE_HTTPD_RSRC_PROXY_DNS_SERVER      = (1 << 5), /* dns address specified */
+	QSE_HTTPD_RSRC_PROXY_URS_SERVER      = (1 << 6), /* urs address specified */
 };
 
 typedef struct qse_httpd_rsrc_proxy_t qse_httpd_rsrc_proxy_t;
diff --git a/qse/include/qse/sed/Makefile.in b/qse/include/qse/sed/Makefile.in
index 5a776e6a..5d5891e4 100644
--- a/qse/include/qse/sed/Makefile.in
+++ b/qse/include/qse/sed/Makefile.in
@@ -56,6 +56,7 @@ DIST_COMMON = $(am__pkginclude_HEADERS_DIST) $(srcdir)/Makefile.am \
 	$(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/include/qse/xli/Makefile.in b/qse/include/qse/xli/Makefile.in
index 2f3ecadb..7e02e71c 100644
--- a/qse/include/qse/xli/Makefile.in
+++ b/qse/include/qse/xli/Makefile.in
@@ -55,6 +55,7 @@ DIST_COMMON = $(pkginclude_HEADERS) $(srcdir)/Makefile.am \
 	$(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/lib/Makefile.in b/qse/lib/Makefile.in
index 8b922b14..79c5e8de 100644
--- a/qse/lib/Makefile.in
+++ b/qse/lib/Makefile.in
@@ -54,6 +54,7 @@ subdir = lib
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/lib/awk/Makefile.in b/qse/lib/awk/Makefile.in
index d85c025c..b513be80 100644
--- a/qse/lib/awk/Makefile.in
+++ b/qse/lib/awk/Makefile.in
@@ -80,6 +80,7 @@ subdir = lib/awk
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/lib/cmn/Makefile.am b/qse/lib/cmn/Makefile.am
index e9296c59..b69ad868 100644
--- a/qse/lib/cmn/Makefile.am
+++ b/qse/lib/cmn/Makefile.am
@@ -70,6 +70,7 @@ libqsecmn_la_SOURCES = \
 	pma.c \
 	rbt.c \
 	rex.c \
+	sck.c \
 	sio.c \
 	sll.c \
 	slmb.c \
diff --git a/qse/lib/cmn/Makefile.in b/qse/lib/cmn/Makefile.in
index 0a2ce091..a782ba6b 100644
--- a/qse/lib/cmn/Makefile.in
+++ b/qse/lib/cmn/Makefile.in
@@ -60,6 +60,7 @@ DIST_COMMON = $(noinst_HEADERS) $(srcdir)/Makefile.am \
 	$(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
@@ -109,16 +110,16 @@ am__libqsecmn_la_SOURCES_DIST = alg-base64.c alg-rand.c alg-search.c \
 	fma.c fmt-intmax.c fmt-out.c fs.c fs-err.c fs-move.c glob.c \
 	hton.c ipad.c lda.c main.c mb8.c mbwc.c mbwc-str.c mem.c mux.c \
 	nwad.c nwad-skad.c nwif.c nwif-cfg.c nwio.c oht.c opt.c \
-	path-basename.c path-canon.c pio.c pma.c rbt.c rex.c sio.c \
-	sll.c slmb.c str-beg.c str-cat.c str-chr.c str-cnv.c str-cmp.c \
-	str-cpy.c str-del.c str-dup.c str-dyn.c str-end.c str-excl.c \
-	str-fcpy.c str-fmt.c str-fnmat.c str-incl.c str-join.c \
-	str-len.c str-pac.c str-pbrk.c str-put.c str-rev.c str-rot.c \
-	str-set.c str-spl.c str-spn.c str-str.c str-subst.c str-tok.c \
-	str-trm.c str-word.c task.c time.c tio.c tmr.c tre.c tre-ast.c \
-	tre-compile.c tre-match-backtrack.c tre-match-parallel.c \
-	tre-parse.c tre-stack.c uri.c utf8.c xma.c uni.c cp949.c \
-	cp950.c
+	path-basename.c path-canon.c pio.c pma.c rbt.c rex.c sck.c \
+	sio.c sll.c slmb.c str-beg.c str-cat.c str-chr.c str-cnv.c \
+	str-cmp.c str-cpy.c str-del.c str-dup.c str-dyn.c str-end.c \
+	str-excl.c str-fcpy.c str-fmt.c str-fnmat.c str-incl.c \
+	str-join.c str-len.c str-pac.c str-pbrk.c str-put.c str-rev.c \
+	str-rot.c str-set.c str-spl.c str-spn.c str-str.c str-subst.c \
+	str-tok.c str-trm.c str-word.c task.c time.c tio.c tmr.c tre.c \
+	tre-ast.c tre-compile.c tre-match-backtrack.c \
+	tre-match-parallel.c tre-parse.c tre-stack.c uri.c utf8.c \
+	xma.c uni.c cp949.c cp950.c
 @ENABLE_BUNDLED_UNICODE_TRUE@am__objects_1 = uni.lo
 @ENABLE_XCMGRS_TRUE@am__objects_2 = cp949.lo cp950.lo
 am_libqsecmn_la_OBJECTS = alg-base64.lo alg-rand.lo alg-search.lo \
@@ -127,7 +128,7 @@ am_libqsecmn_la_OBJECTS = alg-base64.lo alg-rand.lo alg-search.lo \
 	fs-move.lo glob.lo hton.lo ipad.lo lda.lo main.lo mb8.lo \
 	mbwc.lo mbwc-str.lo mem.lo mux.lo nwad.lo nwad-skad.lo nwif.lo \
 	nwif-cfg.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 \
+	path-canon.lo pio.lo pma.lo rbt.lo rex.lo sck.lo sio.lo sll.lo \
 	slmb.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-dyn.lo str-end.lo \
 	str-excl.lo str-fcpy.lo str-fmt.lo str-fnmat.lo str-incl.lo \
@@ -416,16 +417,16 @@ libqsecmn_la_SOURCES = alg-base64.c alg-rand.c alg-search.c alg-sort.c \
 	fmt-intmax.c fmt-out.c fs.c fs-err.c fs-move.c glob.c hton.c \
 	ipad.c lda.c main.c mb8.c mbwc.c mbwc-str.c mem.c mux.c nwad.c \
 	nwad-skad.c nwif.c nwif-cfg.c nwio.c oht.c opt.c \
-	path-basename.c path-canon.c pio.c pma.c rbt.c rex.c sio.c \
-	sll.c slmb.c str-beg.c str-cat.c str-chr.c str-cnv.c str-cmp.c \
-	str-cpy.c str-del.c str-dup.c str-dyn.c str-end.c str-excl.c \
-	str-fcpy.c str-fmt.c str-fnmat.c str-incl.c str-join.c \
-	str-len.c str-pac.c str-pbrk.c str-put.c str-rev.c str-rot.c \
-	str-set.c str-spl.c str-spn.c str-str.c str-subst.c str-tok.c \
-	str-trm.c str-word.c task.c time.c tio.c tmr.c tre.c tre-ast.c \
-	tre-compile.c tre-match-backtrack.c tre-match-parallel.c \
-	tre-parse.c tre-stack.c uri.c utf8.c xma.c $(am__append_1) \
-	$(am__append_2)
+	path-basename.c path-canon.c pio.c pma.c rbt.c rex.c sck.c \
+	sio.c sll.c slmb.c str-beg.c str-cat.c str-chr.c str-cnv.c \
+	str-cmp.c str-cpy.c str-del.c str-dup.c str-dyn.c str-end.c \
+	str-excl.c str-fcpy.c str-fmt.c str-fnmat.c str-incl.c \
+	str-join.c str-len.c str-pac.c str-pbrk.c str-put.c str-rev.c \
+	str-rot.c str-set.c str-spl.c str-spn.c str-str.c str-subst.c \
+	str-tok.c str-trm.c str-word.c task.c time.c tio.c tmr.c tre.c \
+	tre-ast.c tre-compile.c tre-match-backtrack.c \
+	tre-match-parallel.c tre-parse.c tre-stack.c uri.c utf8.c \
+	xma.c $(am__append_1) $(am__append_2)
 libqsecmn_la_LDFLAGS = -version-info 1:0:0 -no-undefined
 libqsecmn_la_LIBADD = $(SOCKET_LIBS) $(QUADMATH_LIBS)
 @ENABLE_CXX_TRUE@libqsecmnxx_la_SOURCES = \
@@ -555,6 +556,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pma.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/rbt.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/rex.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/sck.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/sio.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/sll.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/slmb.Plo@am__quote@
diff --git a/qse/lib/cmn/nwio.c b/qse/lib/cmn/nwio.c
index 0e0ca29c..37e09305 100644
--- a/qse/lib/cmn/nwio.c
+++ b/qse/lib/cmn/nwio.c
@@ -377,11 +377,7 @@ int qse_nwio_init (
 	int flags, const qse_nwio_tmout_t* tmout)
 {
 	qse_skad_t addr;
-#if defined(HAVE_SOCKLEN_T)
-	socklen_t addrlen;
-#else
-	int addrlen;
-#endif
+	qse_sck_len_t addrlen;
 	int family, type, tmp;
 
 	QSE_MEMSET (nwio, 0, QSE_SIZEOF(*nwio));
@@ -744,11 +740,7 @@ int qse_nwio_init (
 			if (wait_for_data (nwio, &nwio->tmout.c, 1) <= -1) goto oops;
 			else 
 			{
-			#if defined(HAVE_SOCKLEN_T)
-				socklen_t xlen;
-			#else
-				int xlen;
-			#endif
+				qse_sck_len_t xlen;
 				xlen = QSE_SIZEOF(xret);
 				if (getsockopt (nwio->handle, SOL_SOCKET, SO_ERROR, (char*)&xret, &xlen) <= -1)
 				{
@@ -766,7 +758,7 @@ int qse_nwio_init (
 		{
 			xret = connect (nwio->handle, (struct sockaddr*)&addr, addrlen);
 			if (xret <= -1)
-			{	
+			{
 				nwio->errnum = skerr_to_errnum (errno);
 				goto oops;
 			}
@@ -810,18 +802,7 @@ oops:
 		nwio->tio = QSE_NULL;
 	}
 
-#if defined(_WIN32)
-	if (nwio->handle != INVALID_SOCKET) closesocket (nwio->handle);
-
-#elif defined(__OS2__)
-	if (nwio->handle >= 0) soclose (nwio->handle);
-
-#elif defined(__DOS__)
-	/* TODO: */
-
-#else
-	if (nwio->handle >= 0) QSE_CLOSE (nwio->handle);
-#endif
+	if (qse_isvalidsckhnd(nwio->handle)) qse_closesckhnd (nwio->handle);
 	return -1;
 }
 
@@ -835,15 +816,7 @@ void qse_nwio_fini (qse_nwio_t* nwio)
 		nwio->tio = QSE_NULL;
 	}
 
-#if defined(_WIN32)
-	closesocket (nwio->handle);
-#elif defined(__OS2__)
-	/* TODO: */
-#elif defined(__DOS__)
-	/* TODO: */
-#else
-	QSE_CLOSE (nwio->handle);
-#endif
+	qse_closesckhnd (nwio->handle);
 }
 
 qse_mmgr_t* qse_nwio_getmmgr (qse_nwio_t* nwio)
@@ -1031,11 +1004,7 @@ reread:
 	if (nwio->status & STATUS_UDP_CONNECT)
 	{
 		qse_skad_t addr;
-#if defined(HAVE_SOCKLEN_T)
-		socklen_t addrlen;
-#else
-		int addrlen;
-#endif
+		qse_sck_len_t addrlen;
 
 		addrlen = QSE_SIZEOF(addr);
 
diff --git a/qse/lib/cmn/sck.c b/qse/lib/cmn/sck.c
new file mode 100644
index 00000000..39deeb0e
--- /dev/null
+++ b/qse/lib/cmn/sck.c
@@ -0,0 +1,202 @@
+/*
+ * $Id$
+ *
+    Copyright 2006-2014 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/>.
+ */
+
+#include <qse/cmn/sck.h>
+
+#if defined(_WIN32)
+#	include <winsock2.h>
+#	include <ws2tcpip.h> /* sockaddr_in6 */
+#	include <windows.h>
+#elif defined(__OS2__)
+#	if defined(TCPV40HDRS)
+#		define  BSD_SELECT
+#	endif
+#	include <types.h>
+#	include <sys/socket.h>
+#	include <netinet/in.h>
+#	include <sys/ioctl.h>
+#	include <nerrno.h>
+#	if defined(TCPV40HDRS)
+#		define  USE_SELECT
+#		include <sys/select.h>
+#	else
+#		include <unistd.h>
+#	endif
+#elif defined(__DOS__)
+ 	/* TODO:  consider watt-32 */
+#else
+#	include "syscall.h"
+#	include <sys/socket.h>
+#	include <netinet/in.h>
+#	if defined(HAVE_NETINET_SCTP_H)
+#		include <netinet/sctp.h>
+#	endif
+#endif
+
+
+QSE_INLINE int qse_isvalidsckhnd (qse_sck_hnd_t handle)
+{
+#if defined(_WIN32)
+	return handle != QSE_INVALID_SCKHND;
+
+#elif defined(__OS2__)
+	return handle >= 0;
+
+#elif defined(__DOS__)
+	/* TODO: */
+	return 0;
+#else
+	return handle >= 0;
+#endif
+}
+
+QSE_INLINE void qse_closesckhnd (qse_sck_hnd_t handle)
+{
+#if defined(_WIN32)
+	closesocket (handle);
+#elif defined(__OS2__)
+	soclose (handle);
+#elif defined(__DOS__)
+	/* TODO: */
+#else
+	QSE_CLOSE (handle);
+#endif
+}
+
+#if 0
+qse_sck_hnd_t
+
+
+int qse_sck_open (qse_mmgr_t* mmgr, qse_sck_type_t type)
+{
+}
+
+void qse_sck_close (qse_sck_t* sck)
+{
+}
+
+int qse_sck_init (qse_sck_t* sck, qse_mmgr_t* mmgr, qse_sck_type_t type)
+{
+	int domain, type, proto = 0;
+
+	switch (type)
+	{
+		case QSE_SCK_TCP4:
+			domain = AF_INET;
+			type = SOCK_STREAM;
+			break;
+
+		case QSE_SCK_TCP6:
+			domain = AF_INET6;
+			type = SOCK_STREAM;
+			break;
+
+		case QSE_SCK_UDP4:
+			domain = AF_INET;
+			type = SOCK_DGRAM;
+			break;
+
+		case QSE_SCK_UDP6:
+			domain = AF_INET6;
+			type = SOCK_DGRAM;
+			break;
+
+		case QSE_SCK_SCTP4:
+			domain = AF_INET;
+			type = SCOK_SEQPACKET;
+			proto = IPPROTO_SCTP;
+			break;
+
+		case QSE_SCK_SCTP6:
+			domain = AF_INET6;
+			type = SCOK_SEQPACKET;
+			proto = IPPROTO_SCTP;
+			break;
+
+		case QSE_SCK_SCTP4:
+			domain = AF_INET;
+			type = SCOK_STREAM;
+			proto = IPPROTO_SCTP;
+			break;
+
+		case QSE_SCK_SCTP6:
+			domain = AF_INET6;
+			type = SCOK_STREAM;
+			proto = IPPROTO_SCTP;
+			break;
+
+#if 0
+		case QSE_SCK_RAW4:
+			domain = AF_INET;
+			type = SOCK_RAW;
+			break;
+
+		case QSE_SCK_RAW6:
+			domain = AF_INET6;
+			type = SOCK_RAW;
+			break;
+
+		case QSE_SCK_PACKET:
+			domain = AF_PACKET;
+			type = SOCK_RAW;
+			proto = qse_hton16(ETH_P_ALL);
+			break;
+
+		case QSE_SCK_PACKET:
+			domain = AF_PACKET;
+			type = SOCK_DGRAM; /* cooked packet with the link level header removed */
+			proto = qse_hton16(ETH_P_ALL);
+			break;
+
+		case QSE_SCK_ARP:
+			domain = AF_PACKET;
+			type = SOCK_RAW;
+			proto = qse_hton16(ETH_P_ARP);
+			proto = 
+#endif
+	}
+
+	sck->handle = socket (domain, type, proto);
+}
+
+void qse_sck_fini (qse_sck_t* sck)
+{
+#if defined(_WIN32)
+	closesocket (sck->handle);
+#elif defined(__OS2__)
+	soclose (sck->handle);
+#elif defined(__DOS__)
+	/* TODO: */
+#else
+	QSE_CLOSE (sck->handle);
+#endif
+}
+
+
+qse_ssize_t qse_recvsocket ()
+
+qse_ssize_t recvfromsocket ()
+
+qse_ssize_t sendsocket ()
+qse_ssize_t sendtosocket ()
+#endif
+
+
+
diff --git a/qse/lib/http/Makefile.am b/qse/lib/http/Makefile.am
index 603cb218..d3a00108 100644
--- a/qse/lib/http/Makefile.am
+++ b/qse/lib/http/Makefile.am
@@ -24,5 +24,5 @@ libqsehttp_la_SOURCES = \
 	upxd.c
 
 libqsehttp_la_LDFLAGS = -L../cmn -version-info 1:0:0 -no-undefined
-libqsehttp_la_LIBADD = -lqsecmn $(SOCKET_LIBS) $(SENDFILE_LIBS) $(SSL_LIBS)
+libqsehttp_la_LIBADD = -lqsecmn $(SOCKET_LIBS) $(SENDFILE_LIBS) $(SSL_LIBS) 
 
diff --git a/qse/lib/http/Makefile.in b/qse/lib/http/Makefile.in
index ffadb49a..099a35a7 100644
--- a/qse/lib/http/Makefile.in
+++ b/qse/lib/http/Makefile.in
@@ -55,6 +55,7 @@ subdir = lib/http
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
@@ -345,7 +346,7 @@ libqsehttp_la_SOURCES = \
 	upxd.c
 
 libqsehttp_la_LDFLAGS = -L../cmn -version-info 1:0:0 -no-undefined
-libqsehttp_la_LIBADD = -lqsecmn $(SOCKET_LIBS) $(SENDFILE_LIBS) $(SSL_LIBS)
+libqsehttp_la_LIBADD = -lqsecmn $(SOCKET_LIBS) $(SENDFILE_LIBS) $(SSL_LIBS) 
 all: all-am
 
 .SUFFIXES:
diff --git a/qse/lib/http/httpd-dir.c b/qse/lib/http/httpd-dir.c
index 0dd9a0ca..7f7f9264 100644
--- a/qse/lib/http/httpd-dir.c
+++ b/qse/lib/http/httpd-dir.c
@@ -545,7 +545,7 @@ static QSE_INLINE int task_main_getdir (
 				qse_httpd_reqsum_t reqsum;
 
 				acc.remote = remote;
-				acc.qpath = qpath;	
+				acc.qpath = qpath;
 				acc.status = 200;
 				acc.version =  ...;
 				acc.method =  ...;
diff --git a/qse/lib/http/httpd-std-dns.h b/qse/lib/http/httpd-std-dns.h
index eeff1fef..3faad9b8 100644
--- a/qse/lib/http/httpd-std-dns.h
+++ b/qse/lib/http/httpd-std-dns.h
@@ -357,12 +357,11 @@ static int dns_open (qse_httpd_t* httpd, qse_httpd_dns_t* dns)
 		httpd->opt.rcb.logact (httpd, &msg);
 	}
 
-	dns->handle[0].i = open_udp_socket (httpd, AF_INET);
+	dns->handle[0].i = open_udp_socket (httpd, AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 #if defined(AF_INET6)
-	dns->handle[1].i = open_udp_socket (httpd, AF_INET6);
+	dns->handle[1].i = open_udp_socket (httpd, AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
 #endif
-	if (!is_valid_socket(dns->handle[0].i) && 
-	    !is_valid_socket(dns->handle[1].i))
+	if (!qse_isvalidsckhnd(dns->handle[0].i) && !qse_isvalidsckhnd(dns->handle[1].i))
 	{
 		goto oops;
 	}
@@ -380,7 +379,7 @@ static int dns_open (qse_httpd_t* httpd, qse_httpd_dns_t* dns)
 	}
 	else
 	{
-		dc->dns_socket = SOCK_INVALID;
+		dc->dns_socket = QSE_INVALID_SCKHND;
 	}
 
 	dns->handle_count = 2;
@@ -389,8 +388,8 @@ static int dns_open (qse_httpd_t* httpd, qse_httpd_dns_t* dns)
 	return 0;
 
 oops:
-	if (is_valid_socket(dns->handle[0].i)) close_socket (dns->handle[0].i);
-	if (is_valid_socket(dns->handle[1].i)) close_socket (dns->handle[1].i);
+	if (qse_isvalidsckhnd(dns->handle[0].i)) qse_closesckhnd (dns->handle[0].i);
+	if (qse_isvalidsckhnd(dns->handle[1].i)) qse_closesckhnd (dns->handle[1].i);
 	if (dc) qse_httpd_freemem (httpd, dc);
 	return -1;
 
@@ -441,8 +440,8 @@ static void dns_close (qse_httpd_t* httpd, qse_httpd_dns_t* dns)
 
 	for (i = 0; i < dns->handle_count; i++) 
 	{
-		if (is_valid_socket(dns->handle[i].i))
-			close_socket (dns->handle[i].i);
+		if (qse_isvalidsckhnd(dns->handle[i].i))
+			qse_closesckhnd (dns->handle[i].i);
 	}
 	qse_httpd_freemem (httpd, dns->ctx);
 }
diff --git a/qse/lib/http/httpd-std-urs.h b/qse/lib/http/httpd-std-urs.h
index 8a0cc851..af1471df 100644
--- a/qse/lib/http/httpd-std-urs.h
+++ b/qse/lib/http/httpd-std-urs.h
@@ -33,10 +33,10 @@ typedef struct urs_req_t urs_req_t;
 #include <qse/pack1.h>
 struct urs_hdr_t
 {
-	qse_uint16_t seq; /* in network-byte order */
-	qse_uint16_t rcode; /* response code */
-	qse_uint32_t qusum;/* checksum of url in the request */
-	qse_uint16_t len; /* url length in network-byte order */
+	qse_uint16_t seq;    /* in network-byte order */
+	qse_uint16_t rcode;  /* response code */
+	qse_uint32_t urlsum; /* checksum of url in the request */
+	qse_uint16_t urllen; /* url length in network-byte order */
 };
 
 struct urs_pkt_t
@@ -95,6 +95,7 @@ static int urs_open (qse_httpd_t* httpd, qse_httpd_urs_t* urs)
 	qse_nwad_t nwad;
 	urs_ctx_t* dc;
 	httpd_xtn_t* httpd_xtn;
+	int type, proto = IPPROTO_SCTP;
 
 	httpd_xtn = qse_httpd_getxtn (httpd);
 
@@ -118,12 +119,14 @@ static int urs_open (qse_httpd_t* httpd, qse_httpd_urs_t* urs)
 		httpd->opt.rcb.logact (httpd, &msg);
 	}
 
-	urs->handle[0].i = open_udp_socket (httpd, AF_INET);
+	type = (proto == IPPROTO_SCTP)? SOCK_SEQPACKET: SOCK_DGRAM;
+	
+	urs->handle[0].i = open_udp_socket (httpd, AF_INET, type, proto);
 #if defined(AF_INET6)
-	urs->handle[1].i = open_udp_socket (httpd, AF_INET6);
+	urs->handle[1].i = open_udp_socket (httpd, AF_INET6, type, proto);
 #endif
-	if (!is_valid_socket(urs->handle[0].i) && 
-	    !is_valid_socket(urs->handle[1].i))
+
+	if (!qse_isvalidsckhnd(urs->handle[0].i) && !qse_isvalidsckhnd(urs->handle[1].i))
 	{
 		goto oops;
 	}
@@ -141,17 +144,23 @@ static int urs_open (qse_httpd_t* httpd, qse_httpd_urs_t* urs)
 	}
 	else
 	{
-		dc->urs_socket = SOCK_INVALID;
+		dc->urs_socket = QSE_INVALID_SCKHND;
 	}
 
+	if (proto == IPPROTO_SCTP)
+	{
+/* TODO: error ahndleing */
+		if (qse_isvalidsckhnd(urs->handle[0].i)) listen (urs->handle[0].i, 99);
+		if (qse_isvalidsckhnd(urs->handle[1].i)) listen (urs->handle[1].i, 99);
+	}
 	urs->handle_count = 2;
 
 	urs->ctx = dc;
 	return 0;
 
 oops:
-	if (is_valid_socket(urs->handle[0].i)) close_socket (urs->handle[0].i);
-	if (is_valid_socket(urs->handle[1].i)) close_socket (urs->handle[1].i);
+	if (qse_isvalidsckhnd(urs->handle[0].i)) qse_closesckhnd (urs->handle[0].i);
+	if (qse_isvalidsckhnd(urs->handle[1].i)) qse_closesckhnd (urs->handle[1].i);
 	if (dc) qse_httpd_freemem (httpd, dc);
 	return -1;
 
@@ -189,8 +198,8 @@ static void urs_close (qse_httpd_t* httpd, qse_httpd_urs_t* urs)
 
 	for (i = 0; i < urs->handle_count; i++) 
 	{
-		if (is_valid_socket(urs->handle[i].i)) 
-			close_socket (urs->handle[i].i);
+		if (qse_isvalidsckhnd(urs->handle[i].i)) 
+			qse_closesckhnd (urs->handle[i].i);
 	}
 
 	qse_httpd_freemem (httpd, urs->ctx);
@@ -220,15 +229,16 @@ printf ("URS_RECV....\n");
 /* TODO: check if fromaddr matches the dc->skad... */
 
 	pkt = (urs_pkt_t*)dc->rcvbuf;
-	if (len >= QSE_SIZEOF(pkt->hdr) &&  len >= QSE_SIZEOF(pkt->hdr) + qse_ntoh16(pkt->hdr.len))
+	if (len >= QSE_SIZEOF(pkt->hdr) &&  len >= QSE_SIZEOF(pkt->hdr) + qse_ntoh16(pkt->hdr.urllen))
 	{
 		xid = qse_ntoh16(pkt->hdr.seq) % QSE_COUNTOF(dc->reqs);
 
 		for (req = dc->reqs[xid]; req; req = req->next)
 		{
-			if (req->pkt->hdr.seq == pkt->hdr.seq && req->pkt->hdr.qusum == pkt->hdr.qusum)
+			if (req->pkt->hdr.seq == pkt->hdr.seq && req->pkt->hdr.urlsum == pkt->hdr.urlsum)
 			{
-				pkt->url[qse_ntoh16(pkt->hdr.len)] = QSE_MT('\0');
+				/* null-terminate the url for easier processing */
+				pkt->url[qse_ntoh16(pkt->hdr.urllen)] = QSE_MT('\0');
 
 				urs_remove_tmr_tmout (httpd, req);
 				req->rewrite (httpd, req->pkt->url, pkt->url, req->ctx);
@@ -329,11 +339,10 @@ static int urs_send (qse_httpd_t* httpd, qse_httpd_urs_t* urs, const qse_mchar_t
 	urs_req_t* req = QSE_NULL;
 	qse_size_t url_len;
 	qse_tmr_event_t tmout_event;
+	
 
 	httpd_xtn = qse_httpd_getxtn (httpd);
 
-printf ("URS REALLY SENING>>>>>>>>>>>>>>>>>>>>>>>\n");
-
 	if (dc->req_count >= QSE_COUNTOF(dc->reqs))
 	{
 		/* too many pending requests */
@@ -361,8 +370,8 @@ printf ("URS REALLY SENING>>>>>>>>>>>>>>>>>>>>>>>\n");
 	req->pkt = (urs_pkt_t*)(req + 1);
 
 	req->pkt->hdr.seq = qse_hton16(seq);
-	req->pkt->hdr.len = qse_hton16(url_len);
-	req->pkt->hdr.qusum = hash_string (url);
+	req->pkt->hdr.urllen = qse_hton16(url_len);
+	req->pkt->hdr.urlsum = hash_string (url);
 	qse_mbscpy (req->pkt->url, url);
 
 	/* -1 to exclude the terminating '\0' as urs_pkt_t has url[1]. */
@@ -412,6 +421,21 @@ printf ("URS REALLY SENING>>>>>>>>>>>>>>>>>>>>>>>\n");
 	tmout_event.updater = tmr_urs_tmout_update;
 	if (qse_httpd_inserttimerevent (httpd, &tmout_event, &req->tmr_tmout) <= -1) goto oops;
 
+/*
+  {
+  struct msghdr msg;
+	struct iovec iov;
+	QSE_MEMSET (&msg, 0, QSE_SIZEOF(msg));
+	msg.msg_name = &req->urs_skad;
+	msg.msg_namelen = req->urs_skadlen;
+	iov.iov_base = req->pkt;
+	iov.iov_len = req->pktlen;
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+	if (sendmsg (req->urs_socket, &msg, 0) != req->pktlen) 
+}
+*/
+
 	if (sendto (req->urs_socket, req->pkt, req->pktlen, 0, (struct sockaddr*)&req->urs_skad, req->urs_skadlen) != req->pktlen)
 	{
 		qse_httpd_seterrnum (httpd, SKERR_TO_ERRNUM());
diff --git a/qse/lib/http/httpd-std.c b/qse/lib/http/httpd-std.c
index 1465c71f..3a886215 100644
--- a/qse/lib/http/httpd-std.c
+++ b/qse/lib/http/httpd-std.c
@@ -33,6 +33,7 @@
 #include <qse/cmn/dir.h>
 #include <qse/cmn/fio.h>
 #include <qse/cmn/sio.h>
+#include <qse/cmn/sck.h>
 
 #define STAT_REG   1
 #define STAT_DIR   2
@@ -87,6 +88,9 @@
 #			define IP_TRANSPARENT 19
 #		endif
 #	endif
+#	if defined(HAVE_NETINET_SCTP_H)
+#		include <netinet/sctp.h>
+#	endif
 #endif
 
 #if defined(HAVE_SSL)
@@ -651,41 +655,7 @@ void* qse_httpd_getxtnstd (qse_httpd_t* httpd)
 
 /* ------------------------------------------------------------------- */
 
-#if defined(_WIN32)
-	typedef SOCKET sock_t;
-#	define SOCK_INVALID INVALID_SOCKET
-#else
-	typedef int sock_t;
-#	define SOCK_INVALID -1
-#endif
-
-#if !defined(HAVE_SOCKLEN_T)
-	typedef int socklen_t;
-#endif
-
-static QSE_INLINE int is_valid_socket (sock_t fd)
-{
-#if defined(_WIN32)
-	return fd != INVALID_SOCKET;
-#else
-	return fd >= 0;
-#endif
-}
-
-static QSE_INLINE void close_socket (sock_t fd)
-{
-#if defined(_WIN32)
-	closesocket (fd);
-#elif defined(__OS2__)
-	soclose (fd);
-#elif defined(__DOS__)
-	/* TODO: */
-#else
-	QSE_CLOSE (fd);
-#endif
-}
-
-static int set_socket_nonblock (qse_httpd_t* httpd, sock_t fd, int enabled)
+static int set_socket_nonblock (qse_httpd_t* httpd, qse_sck_hnd_t fd, int enabled)
 {
 #if defined(_WIN32)
 	if (ioctlsocket (fd, FIONBIO, &enabled) == SOCKET_ERROR) 
@@ -723,13 +693,13 @@ static int set_socket_nonblock (qse_httpd_t* httpd, sock_t fd, int enabled)
 
 }
 
-static sock_t open_udp_socket (qse_httpd_t* httpd, int domain)
+static qse_sck_hnd_t open_udp_socket (qse_httpd_t* httpd, int domain, int type, int proto)
 {
-	sock_t fd;
+	qse_sck_hnd_t fd;
 	int flag;
 
-	fd = socket (domain, SOCK_DGRAM, IPPROTO_UDP);
-	if (!is_valid_socket(fd)) 
+	fd = socket (domain, type, proto);
+	if (!qse_isvalidsckhnd(fd)) 
 	{
 		qse_httpd_seterrnum (httpd, SKERR_TO_ERRNUM());
 		goto oops;
@@ -750,13 +720,34 @@ static sock_t open_udp_socket (qse_httpd_t* httpd, int domain)
 	setsockopt (fd, SOL_SOCKET, SO_REUSEPORT, (void*)&flag, QSE_SIZEOF(flag));
 	#endif
 
+	#if defined(IPV6_V6ONLY)
+	if (domain == AF_INET6)
+	{
+		flag = 1;
+		setsockopt (fd, IPPROTO_IPV6, IPV6_V6ONLY, (void*)&flag, QSE_SIZEOF(flag));
+	}
+	#endif
+
 	if (set_socket_nonblock (httpd, fd, 1) <= -1) goto oops;
 
+
+	if (proto == IPPROTO_SCTP)
+	{
+		struct sctp_initmsg im;
+
+		QSE_MEMSET (&im, 0, QSE_SIZEOF(im));
+		im.sinit_num_ostreams = 1;
+		im.sinit_max_instreams = 1;
+		im.sinit_max_attempts = 1;
+
+		if (setsockopt (fd, SOL_SCTP, SCTP_INITMSG, &im, QSE_SIZEOF(im)) <= -1) goto oops;
+	}
+
 	return fd;
 
 oops:
-	if (is_valid_socket(fd)) close_socket (fd);
-	return SOCK_INVALID;
+	if (qse_isvalidsckhnd(fd)) qse_closesckhnd (fd);
+	return QSE_INVALID_SCKHND;
 }
 
 /* ------------------------------------------------------------------- */
@@ -767,7 +758,7 @@ static int server_open (qse_httpd_t* httpd, qse_httpd_server_t* server)
 	qse_httpd_seterrnum (httpd, QSE_HTTPD_ENOIMPL);
 	return -1;
 #else
-	sock_t fd = SOCK_INVALID, flag;
+	qse_sck_hnd_t fd = QSE_INVALID_SCKHND, flag;
 	qse_skad_t addr;
 	int addrsize;
 
@@ -779,7 +770,7 @@ static int server_open (qse_httpd_t* httpd, qse_httpd_server_t* server)
 	}
 
 	fd = socket (qse_skadfamily(&addr), SOCK_STREAM, IPPROTO_TCP);
-	if (!is_valid_socket(fd)) 
+	if (!qse_isvalidsckhnd(fd)) 
 	{
 		qse_httpd_seterrnum (httpd, SKERR_TO_ERRNUM());
 		goto oops;
@@ -861,24 +852,15 @@ static int server_open (qse_httpd_t* httpd, qse_httpd_server_t* server)
 		{
 			int on = 1;
 			setsockopt (fd, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on));
-			if (bind (fd, (struct sockaddr*)&addr, addrsize) <= -1)  
-			{
-				qse_httpd_seterrnum (httpd, SKERR_TO_ERRNUM());
-				goto oops;
-			}
+			if (bind (fd, (struct sockaddr*)&addr, addrsize) == 0) goto bind_ok;
 		}
-		else 
-		{
-			qse_httpd_seterrnum (httpd, SKERR_TO_ERRNUM());
-			goto oops;
-		}
-	#else
+	#endif
 
 		qse_httpd_seterrnum (httpd, SKERR_TO_ERRNUM());
 		goto oops;
-	#endif
 	}
 
+bind_ok:
 	if (listen (fd, 10) <= -1) 
 	{
 		qse_httpd_seterrnum (httpd, SKERR_TO_ERRNUM());
@@ -891,14 +873,14 @@ static int server_open (qse_httpd_t* httpd, qse_httpd_server_t* server)
 	return 0;
 
 oops:
-	if (is_valid_socket(fd)) close_socket (fd);
+	if (qse_isvalidsckhnd(fd)) qse_closesckhnd (fd);
 	return -1;
 #endif
 }
 
 static void server_close (qse_httpd_t* httpd, qse_httpd_server_t* server)
 {
-	close_socket (server->handle.i);
+	qse_closesckhnd (server->handle.i);
 }
 
 static int server_accept (
@@ -910,13 +892,13 @@ static int server_accept (
 
 #else
 	qse_skad_t addr;
-	socklen_t addrlen;
-	sock_t fd = SOCK_INVALID;
+	qse_sck_len_t addrlen;
+	qse_sck_hnd_t fd = QSE_INVALID_SCKHND;
 	int flag;
 
 	addrlen = QSE_SIZEOF(addr);
 	fd = accept (server->handle.i, (struct sockaddr*)&addr, &addrlen);
-	if (!is_valid_socket(fd)) 
+	if (!qse_isvalidsckhnd(fd)) 
 	{
 		qse_httpd_seterrnum (httpd, SKERR_TO_ERRNUM());
 		goto oops;
@@ -985,7 +967,7 @@ qse_fprintf (QSE_STDERR, QSE_T("Error: too many client?\n"));
 	return 0;
 
 oops:
-	if (is_valid_socket(fd)) close_socket (fd);
+	if (qse_isvalidsckhnd(fd)) qse_closesckhnd (fd);
 	return -1;
 #endif
 }
@@ -1005,7 +987,8 @@ static int peer_open (qse_httpd_t* httpd, qse_httpd_peer_t* peer)
 	qse_skad_t connaddr, bindaddr;
 	int connaddrsize, bindaddrsize;
 	int connected = 1;
-	sock_t fd = SOCK_INVALID;
+	qse_sck_hnd_t fd = QSE_INVALID_SCKHND;
+
 #if defined(_WIN32)
 	unsigned long cmd;
 #elif defined(__OS2__)
@@ -1026,7 +1009,7 @@ static int peer_open (qse_httpd_t* httpd, qse_httpd_peer_t* peer)
 	bindaddrsize = qse_nwadtoskad (&peer->local, &bindaddr);
 
 	fd = socket (qse_skadfamily(&connaddr), SOCK_STREAM, IPPROTO_TCP);
-	if (!is_valid_socket(fd)) 
+	if (!qse_isvalidsckhnd(fd)) 
 	{
 		qse_httpd_seterrnum (httpd, SKERR_TO_ERRNUM());
 		goto oops;
@@ -1038,6 +1021,7 @@ static int peer_open (qse_httpd_t* httpd, qse_httpd_peer_t* peer)
 	setsockopt (fd, SOL_IP, IP_TRANSPARENT, &flag, QSE_SIZEOF(flag));
 	#endif
 
+	/* don't use invalid binding address */
 	if (bindaddrsize >= 0 &&
 	    bind (fd, (struct sockaddr*)&bindaddr, bindaddrsize) <= -1) 
 	{
@@ -1096,7 +1080,7 @@ static int peer_open (qse_httpd_t* httpd, qse_httpd_peer_t* peer)
 
 oops:
 	qse_httpd_seterrnum (httpd, SKERR_TO_ERRNUM());
-	if (is_valid_socket(fd)) close_socket (fd);
+	if (qse_isvalidsckhnd(fd)) qse_closesckhnd (fd);
 	return -1;
 
 	/* -------------------------------------------------------------------- */
@@ -1105,7 +1089,7 @@ oops:
 
 static void peer_close (qse_httpd_t* httpd, qse_httpd_peer_t* peer)
 {
-	close_socket (peer->handle.i);
+	qse_closesckhnd (peer->handle.i);
 }
 
 static int peer_connected (qse_httpd_t* httpd, qse_httpd_peer_t* peer)
@@ -1159,7 +1143,7 @@ static int peer_connected (qse_httpd_t* httpd, qse_httpd_peer_t* peer)
 
 #else
 
-	socklen_t len;
+	qse_sck_len_t len;
 	int ret;
 
 	len = QSE_SIZEOF(ret);
@@ -1857,7 +1841,7 @@ static void client_close (qse_httpd_t* httpd, qse_httpd_client_t* client)
 #else
 	shutdown (client->handle.i, SHUT_RDWR);
 #endif
-	close_socket (client->handle.i);
+	qse_closesckhnd (client->handle.i);
 }
 
 static void client_shutdown (qse_httpd_t* httpd, qse_httpd_client_t* client)
diff --git a/qse/lib/sed/Makefile.in b/qse/lib/sed/Makefile.in
index 2c82b55c..2451d56b 100644
--- a/qse/lib/sed/Makefile.in
+++ b/qse/lib/sed/Makefile.in
@@ -56,6 +56,7 @@ subdir = lib/sed
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/lib/xli/Makefile.in b/qse/lib/xli/Makefile.in
index daa8d381..68941689 100644
--- a/qse/lib/xli/Makefile.in
+++ b/qse/lib/xli/Makefile.in
@@ -55,6 +55,7 @@ subdir = lib/xli
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/m4/ax_check_sign.m4 b/qse/m4/ax_check_sign.m4
new file mode 100644
index 00000000..3f2e29f7
--- /dev/null
+++ b/qse/m4/ax_check_sign.m4
@@ -0,0 +1,53 @@
+# ===========================================================================
+#       http://www.gnu.org/software/autoconf-archive/ax_check_sign.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CHECK_SIGN (TYPE, [ACTION-IF-SIGNED], [ACTION-IF-UNSIGNED], [INCLUDES])
+#
+# DESCRIPTION
+#
+#   Checks whether TYPE is signed or not. If no INCLUDES are specified, the
+#   default includes are used. If ACTION-IF-SIGNED is given, it is
+#   additional shell code to execute when the type is signed. If
+#   ACTION-IF-UNSIGNED is given, it is executed when the type is unsigned.
+#
+#   This macro assumes that the type exists. Therefore the existence of the
+#   type should be checked before calling this macro. For example:
+#
+#     AC_CHECK_HEADERS([wchar.h])
+#     AC_CHECK_TYPE([wchar_t],,[ AC_MSG_ERROR([Type wchar_t not found.]) ])
+#     AX_CHECK_SIGN([wchar_t],
+#       [ AC_DEFINE(WCHAR_T_SIGNED, 1, [Define if wchar_t is signed]) ],
+#       [ AC_DEFINE(WCHAR_T_UNSIGNED, 1, [Define if wchar_t is unsigned]) ], [
+#     #ifdef HAVE_WCHAR_H
+#     #include <wchar.h>
+#     #endif
+#     ])
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Ville Laurikari <vl@iki.fi>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 6
+
+AC_DEFUN([AX_CHECK_SIGN], [
+ typename=`echo $1 | sed "s/@<:@^a-zA-Z0-9_@:>@/_/g"`
+ AC_CACHE_CHECK([whether $1 is signed], ax_cv_decl_${typename}_signed, [
+   AC_TRY_COMPILE([$4],
+     [ int foo @<:@ 1 - 2 * !((($1) -1) < 0) @:>@ ],
+     [ eval "ax_cv_decl_${typename}_signed=\"yes\"" ],
+     [ eval "ax_cv_decl_${typename}_signed=\"no\"" ])])
+ symbolname=`echo $1 | sed "s/@<:@^a-zA-Z0-9_@:>@/_/g" | tr "a-z" "A-Z"`
+ if eval "test \"\${ax_cv_decl_${typename}_signed}\" = \"yes\""; then
+   $2
+ elif eval "test \"\${ax_cv_decl_${typename}_signed}\" = \"no\""; then
+   $3
+ fi
+])dnl
diff --git a/qse/regress/Makefile.in b/qse/regress/Makefile.in
index 30977b99..63d6403d 100644
--- a/qse/regress/Makefile.in
+++ b/qse/regress/Makefile.in
@@ -54,6 +54,7 @@ subdir = regress
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/regress/awk/Makefile.in b/qse/regress/awk/Makefile.in
index 4d778a55..35f34751 100644
--- a/qse/regress/awk/Makefile.in
+++ b/qse/regress/awk/Makefile.in
@@ -55,6 +55,7 @@ DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in \
 	$(srcdir)/regress.sh.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/regress/sed/Makefile.in b/qse/regress/sed/Makefile.in
index 095222e6..5a873c75 100644
--- a/qse/regress/sed/Makefile.in
+++ b/qse/regress/sed/Makefile.in
@@ -56,6 +56,7 @@ DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in \
 	$(srcdir)/regress.sh.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/samples/Makefile.in b/qse/samples/Makefile.in
index 77f0b4e4..42fbe9f0 100644
--- a/qse/samples/Makefile.in
+++ b/qse/samples/Makefile.in
@@ -54,6 +54,7 @@ subdir = samples
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/samples/awk/Makefile.in b/qse/samples/awk/Makefile.in
index 90fc4557..c78271bc 100644
--- a/qse/samples/awk/Makefile.in
+++ b/qse/samples/awk/Makefile.in
@@ -61,6 +61,7 @@ subdir = samples/awk
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/samples/cmn/Makefile.in b/qse/samples/cmn/Makefile.in
index 1fcf1d8f..0ebd1eca 100644
--- a/qse/samples/cmn/Makefile.in
+++ b/qse/samples/cmn/Makefile.in
@@ -66,6 +66,7 @@ subdir = samples/cmn
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/samples/http/Makefile.in b/qse/samples/http/Makefile.in
index 70ad9eb6..1f09bc96 100644
--- a/qse/samples/http/Makefile.in
+++ b/qse/samples/http/Makefile.in
@@ -57,6 +57,7 @@ subdir = samples/http
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/samples/sed/Makefile.in b/qse/samples/sed/Makefile.in
index 7005f2d5..692ee4c1 100644
--- a/qse/samples/sed/Makefile.in
+++ b/qse/samples/sed/Makefile.in
@@ -59,6 +59,7 @@ subdir = samples/sed
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \
diff --git a/qse/tools/Makefile.in b/qse/tools/Makefile.in
index 955e773e..040db525 100644
--- a/qse/tools/Makefile.in
+++ b/qse/tools/Makefile.in
@@ -54,6 +54,7 @@ subdir = tools
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/argz.m4 \
+	$(top_srcdir)/m4/ax_check_sign.m4 \
 	$(top_srcdir)/m4/ax_cxx_namespace.m4 \
 	$(top_srcdir)/m4/ax_numval.m4 $(top_srcdir)/m4/ax_pthread.m4 \
 	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/ltdl.m4 \