diff --git a/moo/configure b/moo/configure
index 53617c9..6f91175 100755
--- a/moo/configure
+++ b/moo/configure
@@ -658,6 +658,8 @@ MOO_SIZEOF_LONG_LONG
 MOO_SIZEOF_WCHAR_T
 ENABLE_MOD_X11_FALSE
 ENABLE_MOD_X11_TRUE
+ENABLE_MOD_SCK_FALSE
+ENABLE_MOD_SCK_TRUE
 ENABLE_MOD_FFI_FALSE
 ENABLE_MOD_FFI_TRUE
 ENABLE_LIBLTDL_FALSE
@@ -843,6 +845,7 @@ enable_dynamic_module
 enable_static_module
 enable_libltdl
 enable_mod_ffi
+enable_mod_sck
 enable_mod_x11
 '
       ac_precious_vars='build_alias
@@ -1497,6 +1500,7 @@ Optional Features:
                           library(default. no)
   --enable-libltdl        use libltdl(default. yes)
   --enable-mod-ffi        enable mod/ffi (default. yes)
+  --enable-mod-sck        enable mod/sck (default. yes)
   --enable-mod-x11        enable mod/x11 (default. yes)
 
 Optional Packages:
@@ -20845,6 +20849,29 @@ else
 fi
 
 
+# Check whether --enable-mod-sck was given.
+if test "${enable_mod_sck+set}" = set; then :
+  enableval=$enable_mod_sck; enable_mod_sck_is=$enableval
+else
+  enable_mod_sck_is=yes
+
+fi
+
+if test "${enable_mod_sck_is}" = "yes"
+then
+
+$as_echo "#define MOO_ENABLE_MOD_SCK /**/" >>confdefs.h
+
+fi
+ if test "${enable_mod_sck_is}" = "yes"; then
+  ENABLE_MOD_SCK_TRUE=
+  ENABLE_MOD_SCK_FALSE='#'
+else
+  ENABLE_MOD_SCK_TRUE='#'
+  ENABLE_MOD_SCK_FALSE=
+fi
+
+
 # Check whether --enable-mod-x11 was given.
 if test "${enable_mod_x11+set}" = set; then :
   enableval=$enable_mod_x11; enable_mod_x11_is=$enableval
@@ -21091,6 +21118,10 @@ if test -z "${ENABLE_MOD_FFI_TRUE}" && test -z "${ENABLE_MOD_FFI_FALSE}"; then
   as_fn_error $? "conditional \"ENABLE_MOD_FFI\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
 fi
+if test -z "${ENABLE_MOD_SCK_TRUE}" && test -z "${ENABLE_MOD_SCK_FALSE}"; then
+  as_fn_error $? "conditional \"ENABLE_MOD_SCK\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
 if test -z "${ENABLE_MOD_X11_TRUE}" && test -z "${ENABLE_MOD_X11_FALSE}"; then
   as_fn_error $? "conditional \"ENABLE_MOD_X11\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
diff --git a/moo/configure.ac b/moo/configure.ac
index 3924d5f..02567ca 100644
--- a/moo/configure.ac
+++ b/moo/configure.ac
@@ -509,6 +509,18 @@ then
 fi
 AM_CONDITIONAL(ENABLE_MOD_FFI, test "${enable_mod_ffi_is}" = "yes")
 
+dnl ===== enable-mod-sck =====
+AC_ARG_ENABLE([mod-sck],
+	[AS_HELP_STRING([--enable-mod-sck],[enable mod/sck (default. yes)])],
+	enable_mod_sck_is=$enableval,
+	enable_mod_sck_is=yes
+)
+if test "${enable_mod_sck_is}" = "yes"
+then
+	AC_DEFINE([MOO_ENABLE_MOD_SCK],[],[build mod/sck])
+fi
+AM_CONDITIONAL(ENABLE_MOD_SCK, test "${enable_mod_sck_is}" = "yes")
+
 dnl ===== enable-mod-x11 =====
 AC_ARG_ENABLE([mod-x11],
 	[AS_HELP_STRING([--enable-mod-x11],[enable mod/x11 (default. yes)])],
diff --git a/moo/kernel/Socket.moo b/moo/kernel/Socket.moo
new file mode 100644
index 0000000..4ffaee3
--- /dev/null
+++ b/moo/kernel/Socket.moo
@@ -0,0 +1,48 @@
+class Socket(Object) from 'sck'
+{
+	var handle := -1.
+
+	method(#primitive) _open(domain, type, proto).
+	method(#primitive) _connect(a,b,c).
+	method(#primitive) _close.
+}
+
+(* TODO: generate these domain and type from the C header *)
+pooldic Socket.Domain
+{
+	INET := 2.
+	INET6 := 10.
+}
+
+pooldic Socket.Type
+{
+	STREAM := 1.
+	DGRAM  := 2.
+}
+
+extend Socket
+{
+	method(#class) domain: domain type: type
+	{
+		^super new _open(domain, type, 0).
+	}
+
+	method beginConnect
+	{
+		(*
+		| s1 s1 |
+		s1 = Semaphore new.
+		s2 = Semaphore new.
+
+		s1 signalHandler: [xxxxx].
+		s2 signalHandler: [xxxxxx].
+
+		fcntl (nonblock);
+
+		Processor signal: s1 onOutput: self.handle.
+		Processor signal: s2 after: timeout.
+
+		connect ();
+		*)
+	}
+}
diff --git a/moo/kernel/generr.moo b/moo/kernel/generr.moo
index 6885bfb..7486e14 100644
--- a/moo/kernel/generr.moo
+++ b/moo/kernel/generr.moo
@@ -15,6 +15,7 @@ class MyObject(Object)
 			'internal error that should never have happened'
 			'insufficient system memory'
 			'insufficient object memory'
+			'invalid class/type'
 
 			'invalid parameter or argument'
 			'data not found'
diff --git a/moo/lib/Makefile.am b/moo/lib/Makefile.am
index f3d6fc9..8060c2d 100644
--- a/moo/lib/Makefile.am
+++ b/moo/lib/Makefile.am
@@ -76,6 +76,10 @@ if ENABLE_MOD_FFI
 libmoo_la_LIBADD += -lmoo-ffi
 libmoo_la_DEPENDENCIES += $(abs_builddir)/../mod/libmoo-ffi.la
 endif
+if ENABLE_MOD_SCK
+libmoo_la_LIBADD += -lmoo-sck
+libmoo_la_DEPENDENCIES += $(abs_builddir)/../mod/libmoo-sck.la
+endif
 if ENABLE_MOD_X11
 libmoo_la_LIBADD += -lmoo-x11
 libmoo_la_DEPENDENCIES += $(abs_builddir)/../mod/libmoo-x11.la
diff --git a/moo/lib/Makefile.in b/moo/lib/Makefile.in
index 511edc4..2ad657f 100644
--- a/moo/lib/Makefile.in
+++ b/moo/lib/Makefile.in
@@ -100,11 +100,14 @@ host_triplet = @host@
 @ENABLE_STATIC_MODULE_FALSE@	$(am__DEPENDENCIES_3) \
 @ENABLE_STATIC_MODULE_FALSE@	$(am__DEPENDENCIES_1) \
 @ENABLE_STATIC_MODULE_FALSE@	$(am__DEPENDENCIES_1) \
+@ENABLE_STATIC_MODULE_FALSE@	$(am__DEPENDENCIES_1) \
 @ENABLE_STATIC_MODULE_FALSE@	$(am__DEPENDENCIES_1)
 @ENABLE_MOD_FFI_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_6 = -lmoo-ffi
 @ENABLE_MOD_FFI_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_7 = $(abs_builddir)/../mod/libmoo-ffi.la
-@ENABLE_MOD_X11_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_8 = -lmoo-x11
-@ENABLE_MOD_X11_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_9 = $(abs_builddir)/../mod/libmoo-x11.la
+@ENABLE_MOD_SCK_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_8 = -lmoo-sck
+@ENABLE_MOD_SCK_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_9 = $(abs_builddir)/../mod/libmoo-sck.la
+@ENABLE_MOD_X11_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_10 = -lmoo-x11
+@ENABLE_MOD_X11_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_11 = $(abs_builddir)/../mod/libmoo-x11.la
 bin_PROGRAMS = moo$(EXEEXT)
 @ENABLE_STATIC_MODULE_FALSE@moo_DEPENDENCIES = $(am__DEPENDENCIES_3)
 subdir = lib
@@ -451,10 +454,11 @@ libmoo_la_SOURCES = \
 libmoo_la_CPPFLAGS = $(CPPFLAGS_LIB_COMMON)
 libmoo_la_LDFLAGS = $(LDFLAGS_LIB_COMMON)
 libmoo_la_LIBADD = $(LIBADD_LIB_COMMON) $(am__append_5) \
-	$(am__append_6) $(am__append_8)
+	$(am__append_6) $(am__append_8) $(am__append_10)
 @ENABLE_STATIC_MODULE_TRUE@libmoo_la_DEPENDENCIES = $(abs_builddir)/../mod/libmoo-console.la \
 @ENABLE_STATIC_MODULE_TRUE@	$(abs_builddir)/../mod/libmoo-stdio.la \
-@ENABLE_STATIC_MODULE_TRUE@	$(am__append_7) $(am__append_9)
+@ENABLE_STATIC_MODULE_TRUE@	$(am__append_7) $(am__append_9) \
+@ENABLE_STATIC_MODULE_TRUE@	$(am__append_11)
 moo_SOURCES = main.c
 moo_CPPFLAGS = $(CPPFLAGS_LIB_COMMON)
 moo_LDFLAGS = $(LDFLAGS_LIB_COMMON)
diff --git a/moo/lib/comp.c b/moo/lib/comp.c
index 44790e4..239543d 100644
--- a/moo/lib/comp.c
+++ b/moo/lib/comp.c
@@ -5063,6 +5063,10 @@ static int compile_unary_message (moo_t* moo, int to_super)
 		}
 
 		if (emit_double_param_instruction(moo, send_message_cmd[to_super], nargs, index) <= -1) return -1;
+
+		/* In 'super new xxx', xxx is sent to the object returned by new.
+		 * that means it is not sent to 'super' */
+		to_super = 0;
 	}
 	while (TOKEN_TYPE(moo) == MOO_IOTOK_IDENT);
 
@@ -5102,6 +5106,7 @@ static int compile_binary_message (moo_t* moo, int to_super)
 		if (add_symbol_literal(moo, &binsel, 0, &index) <= -1 ||
 		    emit_double_param_instruction(moo, send_message_cmd[to_super], 1, index) <= -1) goto oops;
 
+		to_super = 0; /* In super + 2 - 3, '-' is sent to the return value of '+', not to super */
 		moo->c->mth.binsels.len = saved_binsels_len;
 	}
 	while (TOKEN_TYPE(moo) == MOO_IOTOK_BINSEL);
diff --git a/moo/lib/err.c b/moo/lib/err.c
index 537a5f3..4481f1b 100644
--- a/moo/lib/err.c
+++ b/moo/lib/err.c
@@ -37,36 +37,37 @@ static moo_ooch_t errstr_3[] = {'s','u','b','s','y','s','t','e','m',' ','e','r',
 static moo_ooch_t errstr_4[] = {'i','n','t','e','r','n','a','l',' ','e','r','r','o','r',' ','t','h','a','t',' ','s','h','o','u','l','d',' ','n','e','v','e','r',' ','h','a','v','e',' ','h','a','p','p','e','n','e','d','\0'};
 static moo_ooch_t errstr_5[] = {'i','n','s','u','f','f','i','c','i','e','n','t',' ','s','y','s','t','e','m',' ','m','e','m','o','r','y','\0'};
 static moo_ooch_t errstr_6[] = {'i','n','s','u','f','f','i','c','i','e','n','t',' ','o','b','j','e','c','t',' ','m','e','m','o','r','y','\0'};
-static moo_ooch_t errstr_7[] = {'i','n','v','a','l','i','d',' ','p','a','r','a','m','e','t','e','r',' ','o','r',' ','a','r','g','u','m','e','n','t','\0'};
-static moo_ooch_t errstr_8[] = {'d','a','t','a',' ','n','o','t',' ','f','o','u','n','d','\0'};
-static moo_ooch_t errstr_9[] = {'e','x','i','s','t','i','n','g','/','d','u','p','l','i','c','a','t','e',' ','d','a','t','a','\0'};
-static moo_ooch_t errstr_10[] = {'b','u','s','y','\0'};
-static moo_ooch_t errstr_11[] = {'a','c','c','e','s','s',' ','d','e','n','i','e','d','\0'};
-static moo_ooch_t errstr_12[] = {'o','p','e','r','a','t','i','o','n',' ','n','o','t',' ','p','e','r','m','i','t','t','e','d','\0'};
-static moo_ooch_t errstr_13[] = {'n','o','t',' ','a',' ','d','i','r','e','c','t','o','r','y','\0'};
-static moo_ooch_t errstr_14[] = {'i','n','t','e','r','r','u','p','t','e','d','\0'};
-static moo_ooch_t errstr_15[] = {'p','i','p','e',' ','e','r','r','o','r','\0'};
-static moo_ooch_t errstr_16[] = {'r','e','s','o','u','r','c','e',' ','t','e','m','p','o','r','a','r','i','l','y',' ','u','n','a','v','a','i','l','a','b','l','e','\0'};
-static moo_ooch_t errstr_17[] = {'d','a','t','a',' ','n','o','t',' ','a','v','a','i','l','a','b','l','e','\0'};
-static moo_ooch_t errstr_18[] = {'m','e','s','s','a','g','e',' ','r','e','c','e','i','v','e','r',' ','e','r','r','o','r','\0'};
-static moo_ooch_t errstr_19[] = {'m','e','s','s','a','g','e',' ','s','e','n','d','i','n','g',' ','e','r','r','o','r','\0'};
-static moo_ooch_t errstr_20[] = {'w','r','o','n','g',' ','n','u','m','b','e','r',' ','o','f',' ','a','r','g','u','m','e','n','t','s','\0'};
-static moo_ooch_t errstr_21[] = {'r','a','n','g','e',' ','e','r','r','o','r','\0'};
-static moo_ooch_t errstr_22[] = {'b','y','t','e','-','c','o','d','e',' ','f','u','l','l','\0'};
-static moo_ooch_t errstr_23[] = {'d','i','c','t','i','o','n','a','r','y',' ','f','u','l','l','\0'};
-static moo_ooch_t errstr_24[] = {'p','r','o','c','e','s','s','o','r',' ','f','u','l','l','\0'};
-static moo_ooch_t errstr_25[] = {'s','e','m','a','p','h','o','r','e',' ','h','e','a','p',' ','f','u','l','l','\0'};
-static moo_ooch_t errstr_26[] = {'s','e','m','a','p','h','o','r','e',' ','l','i','s','t',' ','f','u','l','l','\0'};
-static moo_ooch_t errstr_27[] = {'d','i','v','i','d','e',' ','b','y',' ','z','e','r','o','\0'};
-static moo_ooch_t errstr_28[] = {'I','/','O',' ','e','r','r','o','r','\0'};
-static moo_ooch_t errstr_29[] = {'e','n','c','o','d','i','n','g',' ','c','o','n','v','e','r','s','i','o','n',' ','e','r','r','o','r','\0'};
-static moo_ooch_t errstr_30[] = {'b','u','f','f','e','r',' ','f','u','l','l','\0'};
+static moo_ooch_t errstr_7[] = {'i','n','v','a','l','i','d',' ','c','l','a','s','s','/','t','y','p','e','\0'};
+static moo_ooch_t errstr_8[] = {'i','n','v','a','l','i','d',' ','p','a','r','a','m','e','t','e','r',' ','o','r',' ','a','r','g','u','m','e','n','t','\0'};
+static moo_ooch_t errstr_9[] = {'d','a','t','a',' ','n','o','t',' ','f','o','u','n','d','\0'};
+static moo_ooch_t errstr_10[] = {'e','x','i','s','t','i','n','g','/','d','u','p','l','i','c','a','t','e',' ','d','a','t','a','\0'};
+static moo_ooch_t errstr_11[] = {'b','u','s','y','\0'};
+static moo_ooch_t errstr_12[] = {'a','c','c','e','s','s',' ','d','e','n','i','e','d','\0'};
+static moo_ooch_t errstr_13[] = {'o','p','e','r','a','t','i','o','n',' ','n','o','t',' ','p','e','r','m','i','t','t','e','d','\0'};
+static moo_ooch_t errstr_14[] = {'n','o','t',' ','a',' ','d','i','r','e','c','t','o','r','y','\0'};
+static moo_ooch_t errstr_15[] = {'i','n','t','e','r','r','u','p','t','e','d','\0'};
+static moo_ooch_t errstr_16[] = {'p','i','p','e',' ','e','r','r','o','r','\0'};
+static moo_ooch_t errstr_17[] = {'r','e','s','o','u','r','c','e',' ','t','e','m','p','o','r','a','r','i','l','y',' ','u','n','a','v','a','i','l','a','b','l','e','\0'};
+static moo_ooch_t errstr_18[] = {'d','a','t','a',' ','t','o','o',' ','l','a','r','g','e','\0'};
+static moo_ooch_t errstr_19[] = {'m','e','s','s','a','g','e',' ','r','e','c','e','i','v','e','r',' ','e','r','r','o','r','\0'};
+static moo_ooch_t errstr_20[] = {'m','e','s','s','a','g','e',' ','s','e','n','d','i','n','g',' ','e','r','r','o','r','\0'};
+static moo_ooch_t errstr_21[] = {'w','r','o','n','g',' ','n','u','m','b','e','r',' ','o','f',' ','a','r','g','u','m','e','n','t','s','\0'};
+static moo_ooch_t errstr_22[] = {'r','a','n','g','e',' ','e','r','r','o','r','\0'};
+static moo_ooch_t errstr_23[] = {'b','y','t','e','-','c','o','d','e',' ','f','u','l','l','\0'};
+static moo_ooch_t errstr_24[] = {'d','i','c','t','i','o','n','a','r','y',' ','f','u','l','l','\0'};
+static moo_ooch_t errstr_25[] = {'p','r','o','c','e','s','s','o','r',' ','f','u','l','l','\0'};
+static moo_ooch_t errstr_26[] = {'s','e','m','a','p','h','o','r','e',' ','h','e','a','p',' ','f','u','l','l','\0'};
+static moo_ooch_t errstr_27[] = {'s','e','m','a','p','h','o','r','e',' ','l','i','s','t',' ','f','u','l','l','\0'};
+static moo_ooch_t errstr_28[] = {'d','i','v','i','d','e',' ','b','y',' ','z','e','r','o','\0'};
+static moo_ooch_t errstr_29[] = {'I','/','O',' ','e','r','r','o','r','\0'};
+static moo_ooch_t errstr_30[] = {'e','n','c','o','d','i','n','g',' ','c','o','n','v','e','r','s','i','o','n',' ','e','r','r','o','r','\0'};
+static moo_ooch_t errstr_31[] = {'b','u','f','f','e','r',' ','f','u','l','l','\0'};
 static moo_ooch_t* errstr[] =
 {
 	errstr_0, errstr_1, errstr_2, errstr_3, errstr_4, errstr_5, errstr_6, errstr_7,
 	errstr_8, errstr_9, errstr_10, errstr_11, errstr_12, errstr_13, errstr_14, errstr_15,
 	errstr_16, errstr_17, errstr_18, errstr_19, errstr_20, errstr_21, errstr_22, errstr_23,
-	errstr_24, errstr_25, errstr_26, errstr_27, errstr_28, errstr_29, errstr_30 
+	errstr_24, errstr_25, errstr_26, errstr_27, errstr_28, errstr_29, errstr_30, errstr_31
 };
 
 #if defined(MOO_INCLUDE_COMPILER)
@@ -159,14 +160,14 @@ static moo_ooch_t* synerrstr[] =
 /* -------------------------------------------------------------------------- 
  * ERROR NUMBER TO STRING CONVERSION
  * -------------------------------------------------------------------------- */
-const moo_ooch_t* moo_errnumtoerrstr (moo_errnum_t errnum)
+const moo_ooch_t* moo_errnum_to_errstr (moo_errnum_t errnum)
 {
 	static moo_ooch_t e_unknown[] = {'u','n','k','n','o','w','n',' ','e','r','r','o','r','\0'};
 	return (errnum >= 0 && errnum < MOO_COUNTOF(errstr))? errstr[errnum]: e_unknown;
 }
 
 #if defined(MOO_INCLUDE_COMPILER)
-const moo_ooch_t* moo_synerrnumtoerrstr (moo_synerrnum_t errnum)
+const moo_ooch_t* moo_synerrnum_to_errstr (moo_synerrnum_t errnum)
 {
 	static moo_ooch_t e_unknown[] = {'u','n','k','n','o','w','n',' ','e','r','r','o','r','\0'};
 	return (errnum >= 0 && errnum < MOO_COUNTOF(synerrstr))? synerrstr[errnum]: e_unknown;
@@ -213,7 +214,7 @@ const moo_ooch_t* moo_synerrnumtoerrstr (moo_synerrnum_t errnum)
 #	include <errno.h>
 #endif
 
-moo_errnum_t moo_syserrtoerrnum (int e)
+moo_errnum_t moo_syserr_to_errnum (int e)
 {
 #if defined(__OS2__)
 	/* APIRET e */
diff --git a/moo/lib/exec.c b/moo/lib/exec.c
index 0df74ec..422a8ef 100644
--- a/moo/lib/exec.c
+++ b/moo/lib/exec.c
@@ -32,24 +32,6 @@
 #define PROC_STATE_SUSPENDED 0
 #define PROC_STATE_TERMINATED -1
 
-
-/* receiver check failure leads to hard failure.
- * RATIONAL: the primitive handler should be used by relevant classes and
- *           objects only. if the receiver check fails, you must review
- *           your class library */
-#define MOO_PF_CHECK_RCV(moo,cond) do { \
-	if (!(cond)) { moo_seterrnum((moo), MOO_EMSGRCV); return MOO_PF_HARD_FAILURE; } \
-} while(0)
-
-/* argument check failure causes the wrapping method to return an error.
- * RATIONAL: Being a typeless language, it's hard to control the kinds of
- *           arguments.
- */
-#define MOO_PF_CHECK_ARGS(moo,nargs,cond) do { \
-	if (!(cond)) { MOO_STACK_SETRETTOERROR ((moo), (nargs), MOO_EINVAL); return MOO_PF_SUCCESS; } \
-} while(0)
-
-
 static MOO_INLINE const char* proc_state_to_string (int state)
 {
 	static const char* str[] = 
@@ -3357,7 +3339,7 @@ static moo_pfrc_t pf_error_as_string (moo_t* moo, moo_ooi_t nargs)
 	MOO_ASSERT (moo, MOO_IN_SMOOI_RANGE(ec));
 
 /* TODO: error string will be mostly the same.. do i really have to call makestring every time? */
-	s = moo_errnumtoerrstr (ec);
+	s = moo_errnum_to_errstr (ec);
 	ss = moo_makestring (moo, s, moo_countoocstr(s));
 	if (!ss)
 	{
@@ -4667,7 +4649,7 @@ static int start_method (moo_t* moo, moo_oop_method_t method, moo_oow_t nargs)
 				tmp = moo_makestring (moo, moo->errmsg.buf, moo->errmsg.len);
 				moo_poptmp (moo);
 				/* [NOTE] carry on even if instantiation fails */
-				moo->processor->active->perrmsg = tmp? tmp: moo->_nil;
+				moo->processor->active->perrmsg = tmp? tmp: moo->_nil; /* TODO: set to nil or set to an empty string if instantiation fails? */
 			}
 			else
 			{
diff --git a/moo/lib/main.c b/moo/lib/main.c
index dcab672..f545986 100644
--- a/moo/lib/main.c
+++ b/moo/lib/main.c
@@ -849,7 +849,7 @@ static int _add_poll_fd (moo_t* moo, int fd, int event_mask, moo_oow_t event_dat
 	ev.revents = 0;
 	if (write (xtn->ep, &ev, MOO_SIZEOF(ev)) != MOO_SIZEOF(ev))
 	{
-		moo_syserrtoerrnum (errno);
+		moo_syserr_to_errnum (errno);
 		MOO_DEBUG2 (moo, "Cannot add file descriptor %d to devpoll - %hs\n", fd, strerror(errno));
 		return -1;
 	}
@@ -872,7 +872,7 @@ static int _add_poll_fd (moo_t* moo, int fd, int event_mask, moo_oow_t event_dat
 	ev.data.ptr = (void*)event_data;
 	if (epoll_ctl (xtn->ep, EPOLL_CTL_ADD, fd, &ev) == -1)
 	{
-		moo_syserrtoerrnum (errno);
+		moo_syserr_to_errnum (errno);
 		MOO_DEBUG2 (moo, "Cannot add file descriptor %d to epoll - %hs\n", fd, strerror(errno));
 		return -1;
 	}
@@ -956,7 +956,7 @@ static int _del_poll_fd (moo_t* moo, int fd)
 	ev.revents = 0;
 	if (write (xtn->ep, &ev, MOO_SIZEOF(ev)) != MOO_SIZEOF(ev))
 	{
-		moo_syserrtoerrnum (errno);
+		moo_syserr_to_errnum (errno);
 		MOO_DEBUG2 (moo, "Cannot remove file descriptor %d from devpoll - %hs\n", fd, strerror(errno));
 		return -1;
 	}
@@ -971,7 +971,7 @@ static int _del_poll_fd (moo_t* moo, int fd)
 	memset (&ev, 0, MOO_SIZEOF(ev));
 	if (epoll_ctl (xtn->ep, EPOLL_CTL_DEL, fd, &ev) == -1)
 	{
-		moo_syserrtoerrnum (errno);
+		moo_syserr_to_errnum (errno);
 		MOO_DEBUG2 (moo, "Cannot remove file descriptor %d from epoll - %hs\n", fd, strerror(errno));
 		return -1;
 	}
@@ -1053,7 +1053,7 @@ static int _mod_poll_fd (moo_t* moo, int fd, int event_mask, moo_oow_t event_dat
 	ev.data.ptr = (void*)event_data;
 	if (epoll_ctl (xtn->ep, EPOLL_CTL_MOD, fd, &ev) == -1)
 	{
-		moo_syserrtoerrnum (errno);
+		moo_syserr_to_errnum (errno);
 		MOO_DEBUG2 (moo, "Cannot modify file descriptor %d in epoll - %hs\n", fd, strerror(errno));
 		return -1;
 	}
@@ -1131,7 +1131,7 @@ static int vm_startup (moo_t* moo)
 	xtn->ep = open ("/dev/poll", O_RDWR);
 	if (xtn->ep == -1) 
 	{
-		moo_syserrtoerrnum (errno);
+		moo_syserr_to_errnum (errno);
 		MOO_DEBUG1 (moo, "Cannot create devpoll - %hs\n", strerror(errno));
 		goto oops;
 	}
@@ -1147,7 +1147,7 @@ static int vm_startup (moo_t* moo)
 	#endif
 	if (xtn->ep == -1) 
 	{
-		moo_syserrtoerrnum (errno);
+		moo_syserr_to_errnum (errno);
 		MOO_DEBUG1 (moo, "Cannot create epoll - %hs\n", strerror(errno));
 		goto oops;
 	}
@@ -1173,7 +1173,7 @@ static int vm_startup (moo_t* moo)
 #if defined(USE_THREAD)
 	if (pipe(xtn->p) == -1)
 	{
-		moo_syserrtoerrnum (errno);
+		moo_syserr_to_errnum (errno);
 		MOO_DEBUG1 (moo, "Cannot create pipes - %hs\n", strerror(errno));
 		goto oops;
 	}
@@ -2156,12 +2156,12 @@ int main (int argc, char* argv[])
 
 				bcslen = MOO_COUNTOF(bcs);
 			#if defined(MOO_OOCH_IS_UCH)
-				if (moo_convootobcstr (moo, moo_synerrnumtoerrstr(synerr.num), &ucslen, bcs, &bcslen) >= 0)
+				if (moo_convootobcstr (moo, moo_synerrnum_to_errstr(synerr.num), &ucslen, bcs, &bcslen) >= 0)
 				{
 					printf (" [%.*s]", (int)bcslen, bcs);
 				}
 			#else
-				printf (" [%s]", moo_synerrnumtoerrstr(synerr.num));
+				printf (" [%s]", moo_synerrnum_to_errstr(synerr.num));
 			#endif
 
 				if (synerr.tgt.len > 0)
diff --git a/moo/lib/moo-cfg.h.in b/moo/lib/moo-cfg.h.in
index a72f37c..675cc1d 100644
--- a/moo/lib/moo-cfg.h.in
+++ b/moo/lib/moo-cfg.h.in
@@ -350,6 +350,9 @@
 /* build mod/ffi */
 #undef MOO_ENABLE_MOD_FFI
 
+/* build mod/sck */
+#undef MOO_ENABLE_MOD_SCK
+
 /* build mod/x11 */
 #undef MOO_ENABLE_MOD_X11
 
diff --git a/moo/lib/moo.c b/moo/lib/moo.c
index 55da5a9..e34ae34 100644
--- a/moo/lib/moo.c
+++ b/moo/lib/moo.c
@@ -230,12 +230,12 @@ void moo_fini (moo_t* moo)
 
 const moo_ooch_t* moo_geterrstr (moo_t* moo)
 {
-	return moo_errnumtoerrstr (moo->errnum);
+	return moo_errnum_to_errstr (moo->errnum);
 }
 
 const moo_ooch_t* moo_geterrmsg (moo_t* moo)
 {
-	if (moo->errmsg.len <= 0) return moo_errnumtoerrstr (moo->errnum);
+	if (moo->errmsg.len <= 0) return moo_errnum_to_errstr (moo->errnum);
 	return moo->errmsg.buf;
 }
 
@@ -400,6 +400,9 @@ void moo_freemem (moo_t* moo, void* ptr)
 #if defined(MOO_ENABLE_MOD_FFI)
 #	include "../mod/_ffi.h"
 #endif
+#if defined(MOO_ENABLE_MOD_SCK)
+#	include "../mod/_sck.h"
+#endif
 #include "../mod/_stdio.h"
 #if defined(MOO_ENABLE_MOD_X11)
 #	include "../mod/_x11.h"
@@ -415,6 +418,9 @@ static_modtab[] =
 	{ "console",    moo_mod_console },
 #if defined(MOO_ENABLE_MOD_FFI)
 	{ "ffi",        moo_mod_ffi },
+#endif
+#if defined(MOO_ENABLE_MOD_SCK)
+	{ "sck",        moo_mod_sck },
 #endif
 	{ "stdio",      moo_mod_stdio },
 #if defined(MOO_ENABLE_MOD_X11)
diff --git a/moo/lib/moo.h b/moo/lib/moo.h
index 9a9a8e0..5d26f5b 100644
--- a/moo/lib/moo.h
+++ b/moo/lib/moo.h
@@ -48,10 +48,11 @@ enum moo_errnum_t
 	MOO_EGENERIC, /**< generic error */
 
 	MOO_ENOIMPL,  /**< not implemented */
-	MOO_ESYSERR,  /**< subsystem error */
+	MOO_ESYSERR,  /**< system error */
 	MOO_EINTERN,  /**< internal error */
 	MOO_ESYSMEM,  /**< insufficient system memory */
 	MOO_EOOMEM,   /**< insufficient object memory */
+	MOO_ETYPE,    /**< invalid class/type */
 
 	MOO_EINVAL,   /**< invalid parameter or data */
 	MOO_ENOENT,   /**< data not found */
@@ -966,10 +967,8 @@ struct moo_cb_t
 
 
 /* =========================================================================
- * MODULE MANIPULATION
+ * PRIMITIVE FUNCTIONS
  * ========================================================================= */
-#define MOO_MOD_NAME_LEN_MAX 120
-
 enum moo_pfrc_t
 {
 	MOO_PF_HARD_FAILURE = -1,
@@ -1001,6 +1000,28 @@ struct moo_pfinfo_t
 	moo_pfbase_t      base;
 };
 
+
+/* receiver check failure leads to hard failure.
+ * RATIONAL: the primitive handler should be used by relevant classes and
+ *           objects only. if the receiver check fails, you must review
+ *           your class library */
+#define MOO_PF_CHECK_RCV(moo,cond) do { \
+	if (!(cond)) { moo_seterrnum((moo), MOO_EMSGRCV); return MOO_PF_HARD_FAILURE; } \
+} while(0)
+
+/* argument check failure causes the wrapping method to return an error.
+ * RATIONAL: Being a typeless language, it's hard to control the kinds of
+ *           arguments.
+ */
+#define MOO_PF_CHECK_ARGS(moo,nargs,cond) do { \
+	if (!(cond)) { MOO_STACK_SETRETTOERROR ((moo), (nargs), MOO_EINVAL); return MOO_PF_SUCCESS; } \
+} while(0)
+
+/* =========================================================================
+ * MODULE MANIPULATION
+ * ========================================================================= */
+#define MOO_MOD_NAME_LEN_MAX 120
+
 typedef struct moo_mod_t moo_mod_t;
 
 enum moo_mod_hint_t
@@ -2034,11 +2055,11 @@ MOO_EXPORT void moo_assertfailed (
 	moo_oow_t        line
 );
 
-MOO_EXPORT moo_errnum_t moo_syserrtoerrnum (
+MOO_EXPORT moo_errnum_t moo_syserr_to_errnum (
 	int syserr
 );
 
-MOO_EXPORT const moo_ooch_t* moo_errnumtoerrstr (
+MOO_EXPORT const moo_ooch_t* moo_errnum_to_errstr (
 	moo_errnum_t errnum
 );
 
@@ -2059,7 +2080,7 @@ MOO_EXPORT void moo_getsynerr (
 	moo_synerr_t* synerr
 );
 
-MOO_EXPORT const moo_ooch_t* moo_synerrnumtoerrstr (
+MOO_EXPORT const moo_ooch_t* moo_synerrnum_to_errstr (
 	moo_synerrnum_t errnum
 );
 #endif
diff --git a/moo/libltdl/Makefile.in b/moo/libltdl/Makefile.in
index 177e1b1..7586653 100644
--- a/moo/libltdl/Makefile.in
+++ b/moo/libltdl/Makefile.in
@@ -279,12 +279,17 @@ CTAGS = ctags
 CSCOPE = cscope
 AM_RECURSIVE_TARGETS = cscope
 am__DIST_COMMON = $(srcdir)/Makefile.in $(srcdir)/config-h.in \
-	$(top_srcdir)/../ac/compile $(top_srcdir)/../ac/config.guess \
-	$(top_srcdir)/../ac/config.sub $(top_srcdir)/../ac/depcomp \
-	$(top_srcdir)/../ac/install-sh $(top_srcdir)/../ac/ltmain.sh \
-	$(top_srcdir)/../ac/missing ../ac/ar-lib ../ac/compile \
-	../ac/config.guess ../ac/config.sub ../ac/depcomp \
-	../ac/install-sh ../ac/ltmain.sh ../ac/missing COPYING.LIB \
+	$(top_srcdir)/../ac/compile \
+	$(top_srcdir)/../ac/config.guess \
+	$(top_srcdir)/../ac/config.sub \
+	$(top_srcdir)/../ac/depcomp \
+	$(top_srcdir)/../ac/install-sh \
+	$(top_srcdir)/../ac/ltmain.sh \
+	$(top_srcdir)/../ac/missing ../ac/compile \
+	../ac/config.guess ../ac/config.sub \
+	../ac/depcomp ../ac/install-sh \
+	../ac/ltmain.sh \
+	../ac/missing COPYING.LIB \
 	README lt__argz.c lt__dirent.c lt__strl.c
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
 distdir = $(PACKAGE)-$(VERSION)
diff --git a/moo/mod/Makefile.am b/moo/mod/Makefile.am
index 15ddc41..20197ef 100644
--- a/moo/mod/Makefile.am
+++ b/moo/mod/Makefile.am
@@ -23,11 +23,18 @@ if ENABLE_STATIC_MODULE
 LDFLAGS_COMMON =-L$(libdir) -version-info 1:0:0 -no-undefined
 LIBADD_COMMON =
 
-noinst_LTLIBRARIES = libmoo-console.la libmoo-stdio.la
+noinst_LTLIBRARIES =
 
 if ENABLE_MOD_FFI
 noinst_LTLIBRARIES += libmoo-ffi.la
 endif
+
+if ENABLE_MOD_SCK
+noinst_LTLIBRARIES += libmoo-sck.la
+endif
+
+noinst_LTLIBRARIES += libmoo-stdio.la
+
 if ENABLE_MOD_X11
 noinst_LTLIBRARIES += libmoo-x11.la
 endif
@@ -41,11 +48,20 @@ LDFLAGS_COMMON = -L$(abs_builddir)/../lib -L$(libdir) -version-info 1:0:0 -no-un
 LIBADD_COMMON = -lmoo
 
 pkgmodexecdir = $(libdir)
-pkgmodexec_LTLIBRARIES = libmoo-console.la libmoo-stdio.la
+pkgmodexec_LTLIBRARIES =
+
+pkgmodexec_LTLIBRARIES += libmoo-console.la 
 
 if ENABLE_MOD_FFI
 pkgmodexec_LTLIBRARIES += libmoo-ffi.la
 endif
+
+if ENABLE_MOD_SCK
+pkgmodexec_LTLIBRARIES += libmoo-sck.la
+endif
+
+pkgmodexec_LTLIBRARIES += libmoo-stdio.la
+
 if ENABLE_MOD_X11
 pkgmodexec_LTLIBRARIES += libmoo-x11.la
 endif
@@ -64,6 +80,13 @@ libmoo_ffi_la_LDFLAGS = $(LDFLAGS_COMMON)
 libmoo_ffi_la_LIBADD = $(LIBADD_COMMON) $(DYNCALL_LIBS)
 endif
 
+if ENABLE_MOD_SCK
+libmoo_sck_la_SOURCES = sck.c _sck.h
+libmoo_sck_la_CPPFLAGS = $(CPPFLAGS_COMMON)
+libmoo_sck_la_LDFLAGS = $(LDFLAGS_COMMON)
+libmoo_sck_la_LIBADD = $(LIBADD_COMMON)
+endif
+
 libmoo_stdio_la_SOURCES = stdio.c _stdio.h
 libmoo_stdio_la_CPPFLAGS = $(CPPFLAGS_COMMON)
 libmoo_stdio_la_LDFLAGS = $(LDFLAGS_COMMON)
diff --git a/moo/mod/Makefile.in b/moo/mod/Makefile.in
index 2bd3cbe..b18b14b 100644
--- a/moo/mod/Makefile.in
+++ b/moo/mod/Makefile.in
@@ -94,9 +94,11 @@ host_triplet = @host@
 @WIN32_TRUE@am__append_1 = -DMOO_DEFAULT_PFMODPREFIX=\"libmoo-\" -DMOO_DEFAULT_PFMODPOSTFIX=\"-1\"
 @WIN32_FALSE@am__append_2 = -DMOO_DEFAULT_PFMODPREFIX=\"$(libdir)/libmoo-\" -DMOO_DEFAULT_PFMODPOSTFIX=\"\"
 @ENABLE_MOD_FFI_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_3 = libmoo-ffi.la
-@ENABLE_MOD_X11_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_4 = libmoo-x11.la
-@ENABLE_MOD_FFI_TRUE@@ENABLE_STATIC_MODULE_FALSE@am__append_5 = libmoo-ffi.la
-@ENABLE_MOD_X11_TRUE@@ENABLE_STATIC_MODULE_FALSE@am__append_6 = libmoo-x11.la
+@ENABLE_MOD_SCK_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_4 = libmoo-sck.la
+@ENABLE_MOD_X11_TRUE@@ENABLE_STATIC_MODULE_TRUE@am__append_5 = libmoo-x11.la
+@ENABLE_MOD_FFI_TRUE@@ENABLE_STATIC_MODULE_FALSE@am__append_6 = libmoo-ffi.la
+@ENABLE_MOD_SCK_TRUE@@ENABLE_STATIC_MODULE_FALSE@am__append_7 = libmoo-sck.la
+@ENABLE_MOD_X11_TRUE@@ENABLE_STATIC_MODULE_FALSE@am__append_8 = libmoo-x11.la
 subdir = mod
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/ax_cxx_namespace.m4 \
@@ -156,7 +158,6 @@ libmoo_console_la_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC \
 	-o $@
 @ENABLE_STATIC_MODULE_FALSE@am_libmoo_console_la_rpath = -rpath \
 @ENABLE_STATIC_MODULE_FALSE@	$(pkgmodexecdir)
-@ENABLE_STATIC_MODULE_TRUE@am_libmoo_console_la_rpath =
 @ENABLE_MOD_FFI_TRUE@libmoo_ffi_la_DEPENDENCIES =  \
 @ENABLE_MOD_FFI_TRUE@	$(am__DEPENDENCIES_1) \
 @ENABLE_MOD_FFI_TRUE@	$(am__DEPENDENCIES_1)
@@ -170,6 +171,18 @@ libmoo_ffi_la_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
 @ENABLE_MOD_FFI_TRUE@@ENABLE_STATIC_MODULE_FALSE@	-rpath \
 @ENABLE_MOD_FFI_TRUE@@ENABLE_STATIC_MODULE_FALSE@	$(pkgmodexecdir)
 @ENABLE_MOD_FFI_TRUE@@ENABLE_STATIC_MODULE_TRUE@am_libmoo_ffi_la_rpath =
+@ENABLE_MOD_SCK_TRUE@libmoo_sck_la_DEPENDENCIES =  \
+@ENABLE_MOD_SCK_TRUE@	$(am__DEPENDENCIES_1)
+am__libmoo_sck_la_SOURCES_DIST = sck.c _sck.h
+@ENABLE_MOD_SCK_TRUE@am_libmoo_sck_la_OBJECTS = libmoo_sck_la-sck.lo
+libmoo_sck_la_OBJECTS = $(am_libmoo_sck_la_OBJECTS)
+libmoo_sck_la_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
+	$(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
+	$(libmoo_sck_la_LDFLAGS) $(LDFLAGS) -o $@
+@ENABLE_MOD_SCK_TRUE@@ENABLE_STATIC_MODULE_FALSE@am_libmoo_sck_la_rpath =  \
+@ENABLE_MOD_SCK_TRUE@@ENABLE_STATIC_MODULE_FALSE@	-rpath \
+@ENABLE_MOD_SCK_TRUE@@ENABLE_STATIC_MODULE_FALSE@	$(pkgmodexecdir)
+@ENABLE_MOD_SCK_TRUE@@ENABLE_STATIC_MODULE_TRUE@am_libmoo_sck_la_rpath =
 libmoo_stdio_la_DEPENDENCIES = $(am__DEPENDENCIES_1)
 am_libmoo_stdio_la_OBJECTS = libmoo_stdio_la-stdio.lo
 libmoo_stdio_la_OBJECTS = $(am_libmoo_stdio_la_OBJECTS)
@@ -227,9 +240,11 @@ am__v_CCLD_ = $(am__v_CCLD_@AM_DEFAULT_V@)
 am__v_CCLD_0 = @echo "  CCLD    " $@;
 am__v_CCLD_1 = 
 SOURCES = $(libmoo_console_la_SOURCES) $(libmoo_ffi_la_SOURCES) \
-	$(libmoo_stdio_la_SOURCES) $(libmoo_x11_la_SOURCES)
+	$(libmoo_sck_la_SOURCES) $(libmoo_stdio_la_SOURCES) \
+	$(libmoo_x11_la_SOURCES)
 DIST_SOURCES = $(libmoo_console_la_SOURCES) \
-	$(am__libmoo_ffi_la_SOURCES_DIST) $(libmoo_stdio_la_SOURCES) \
+	$(am__libmoo_ffi_la_SOURCES_DIST) \
+	$(am__libmoo_sck_la_SOURCES_DIST) $(libmoo_stdio_la_SOURCES) \
 	$(am__libmoo_x11_la_SOURCES_DIST)
 am__can_run_installinfo = \
   case $$AM_UPDATE_INFO_DIR in \
@@ -435,13 +450,14 @@ CPPFLAGS_COMMON = -I$(abs_builddir) -I$(abs_builddir)/../lib \
 @ENABLE_STATIC_MODULE_TRUE@LDFLAGS_COMMON = -L$(libdir) -version-info 1:0:0 -no-undefined
 @ENABLE_STATIC_MODULE_FALSE@LIBADD_COMMON = -lmoo
 @ENABLE_STATIC_MODULE_TRUE@LIBADD_COMMON = 
-@ENABLE_STATIC_MODULE_TRUE@noinst_LTLIBRARIES = libmoo-console.la \
-@ENABLE_STATIC_MODULE_TRUE@	libmoo-stdio.la $(am__append_3) \
-@ENABLE_STATIC_MODULE_TRUE@	$(am__append_4)
+@ENABLE_STATIC_MODULE_TRUE@noinst_LTLIBRARIES = $(am__append_3) \
+@ENABLE_STATIC_MODULE_TRUE@	$(am__append_4) libmoo-stdio.la \
+@ENABLE_STATIC_MODULE_TRUE@	$(am__append_5)
 @ENABLE_STATIC_MODULE_FALSE@pkgmodexecdir = $(libdir)
 @ENABLE_STATIC_MODULE_FALSE@pkgmodexec_LTLIBRARIES =  \
-@ENABLE_STATIC_MODULE_FALSE@	libmoo-console.la libmoo-stdio.la \
-@ENABLE_STATIC_MODULE_FALSE@	$(am__append_5) $(am__append_6)
+@ENABLE_STATIC_MODULE_FALSE@	libmoo-console.la $(am__append_6) \
+@ENABLE_STATIC_MODULE_FALSE@	$(am__append_7) libmoo-stdio.la \
+@ENABLE_STATIC_MODULE_FALSE@	$(am__append_8)
 libmoo_console_la_SOURCES = console.c console.h
 libmoo_console_la_CPPFLAGS = $(CPPFLAGS_COMMON)
 libmoo_console_la_LDFLAGS = $(LDFLAGS_COMMON)
@@ -450,6 +466,10 @@ libmoo_console_la_LIBADD = $(LIBADD_COMMON) $(TERMINAL_LIBS)
 @ENABLE_MOD_FFI_TRUE@libmoo_ffi_la_CPPFLAGS = $(CPPFLAGS_COMMON)
 @ENABLE_MOD_FFI_TRUE@libmoo_ffi_la_LDFLAGS = $(LDFLAGS_COMMON)
 @ENABLE_MOD_FFI_TRUE@libmoo_ffi_la_LIBADD = $(LIBADD_COMMON) $(DYNCALL_LIBS)
+@ENABLE_MOD_SCK_TRUE@libmoo_sck_la_SOURCES = sck.c _sck.h
+@ENABLE_MOD_SCK_TRUE@libmoo_sck_la_CPPFLAGS = $(CPPFLAGS_COMMON)
+@ENABLE_MOD_SCK_TRUE@libmoo_sck_la_LDFLAGS = $(LDFLAGS_COMMON)
+@ENABLE_MOD_SCK_TRUE@libmoo_sck_la_LIBADD = $(LIBADD_COMMON)
 libmoo_stdio_la_SOURCES = stdio.c _stdio.h
 libmoo_stdio_la_CPPFLAGS = $(CPPFLAGS_COMMON)
 libmoo_stdio_la_LDFLAGS = $(LDFLAGS_COMMON)
@@ -544,6 +564,9 @@ libmoo-console.la: $(libmoo_console_la_OBJECTS) $(libmoo_console_la_DEPENDENCIES
 libmoo-ffi.la: $(libmoo_ffi_la_OBJECTS) $(libmoo_ffi_la_DEPENDENCIES) $(EXTRA_libmoo_ffi_la_DEPENDENCIES) 
 	$(AM_V_CCLD)$(libmoo_ffi_la_LINK) $(am_libmoo_ffi_la_rpath) $(libmoo_ffi_la_OBJECTS) $(libmoo_ffi_la_LIBADD) $(LIBS)
 
+libmoo-sck.la: $(libmoo_sck_la_OBJECTS) $(libmoo_sck_la_DEPENDENCIES) $(EXTRA_libmoo_sck_la_DEPENDENCIES) 
+	$(AM_V_CCLD)$(libmoo_sck_la_LINK) $(am_libmoo_sck_la_rpath) $(libmoo_sck_la_OBJECTS) $(libmoo_sck_la_LIBADD) $(LIBS)
+
 libmoo-stdio.la: $(libmoo_stdio_la_OBJECTS) $(libmoo_stdio_la_DEPENDENCIES) $(EXTRA_libmoo_stdio_la_DEPENDENCIES) 
 	$(AM_V_CCLD)$(libmoo_stdio_la_LINK) $(am_libmoo_stdio_la_rpath) $(libmoo_stdio_la_OBJECTS) $(libmoo_stdio_la_LIBADD) $(LIBS)
 
@@ -558,6 +581,7 @@ distclean-compile:
 
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmoo_console_la-console.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmoo_ffi_la-ffi.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmoo_sck_la-sck.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmoo_stdio_la-stdio.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmoo_x11_la-x11.Plo@am__quote@
 
@@ -599,6 +623,13 @@ libmoo_ffi_la-ffi.lo: ffi.c
 @AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmoo_ffi_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o libmoo_ffi_la-ffi.lo `test -f 'ffi.c' || echo '$(srcdir)/'`ffi.c
 
+libmoo_sck_la-sck.lo: sck.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmoo_sck_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT libmoo_sck_la-sck.lo -MD -MP -MF $(DEPDIR)/libmoo_sck_la-sck.Tpo -c -o libmoo_sck_la-sck.lo `test -f 'sck.c' || echo '$(srcdir)/'`sck.c
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/libmoo_sck_la-sck.Tpo $(DEPDIR)/libmoo_sck_la-sck.Plo
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='sck.c' object='libmoo_sck_la-sck.lo' libtool=yes @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmoo_sck_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o libmoo_sck_la-sck.lo `test -f 'sck.c' || echo '$(srcdir)/'`sck.c
+
 libmoo_stdio_la-stdio.lo: stdio.c
 @am__fastdepCC_TRUE@	$(AM_V_CC)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmoo_stdio_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT libmoo_stdio_la-stdio.lo -MD -MP -MF $(DEPDIR)/libmoo_stdio_la-stdio.Tpo -c -o libmoo_stdio_la-stdio.lo `test -f 'stdio.c' || echo '$(srcdir)/'`stdio.c
 @am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/libmoo_stdio_la-stdio.Tpo $(DEPDIR)/libmoo_stdio_la-stdio.Plo
diff --git a/moo/mod/_sck.h b/moo/mod/_sck.h
new file mode 100644
index 0000000..0b47db9
--- /dev/null
+++ b/moo/mod/_sck.h
@@ -0,0 +1,52 @@
+/*
+ * $Id$
+ *
+    Copyright (c) 2014-2017 Chung, Hyung-Hwan. All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
+    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _MOO_MOD_SCK_H_
+#define _MOO_MOD_SCK_H_
+
+#include <moo.h>
+
+typedef struct sck_t* oop_sck_t;
+struct sck_t
+{
+	MOO_OBJ_HEADER;
+
+	moo_oop_t handle; /* SmallInteger */
+	/* there are more fields in the actual object */
+};
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+MOO_EXPORT int moo_mod_sck (moo_t* moo, moo_mod_t* mod);
+
+#if defined(__cplusplus)
+}
+#endif
+
+
+#endif
diff --git a/moo/mod/ffi.c b/moo/mod/ffi.c
index a281902..dcf048c 100644
--- a/moo/mod/ffi.c
+++ b/moo/mod/ffi.c
@@ -113,7 +113,7 @@ static moo_pfrc_t pf_open (moo_t* moo, moo_ooi_t nargs)
 	dc = dcNewCallVM (4096); /* TODO: right size?  */
 	if (!dc) 
 	{
-		moo_seterrnum (moo, moo_syserrtoerrnum(errno));
+		moo_seterrnum (moo, moo_syserr_to_errnum(errno));
 		moo->vmprim.dl_close (moo, handle);
 		goto softfail;
 	}
diff --git a/moo/mod/sck.c b/moo/mod/sck.c
new file mode 100644
index 0000000..0d3489d
--- /dev/null
+++ b/moo/mod/sck.c
@@ -0,0 +1,208 @@
+/*
+ * $Id$
+ *
+    Copyright (c) 2014-2017 Chung, Hyung-Hwan. All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
+    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "_sck.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+
+static moo_pfrc_t pf_open_socket (moo_t* moo, moo_ooi_t nargs)
+{
+	oop_sck_t sck;
+	moo_oop_t dom, type, proto;
+	int fd = -1;
+	moo_errnum_t errnum;
+
+	sck = (oop_sck_t)MOO_STACK_GETRCV(moo, nargs);
+	MOO_PF_CHECK_RCV (moo, 
+		MOO_OOP_IS_POINTER(sck) &&
+		MOO_OBJ_BYTESOF(sck) >= (MOO_SIZEOF(*sck) - MOO_SIZEOF(moo_obj_t))
+	);
+
+	dom = MOO_STACK_GETARG(moo, nargs, 0);
+	type = MOO_STACK_GETARG(moo, nargs, 1);
+	proto = MOO_STACK_GETARG(moo, nargs, 2);
+
+	MOO_PF_CHECK_ARGS (moo, nargs, MOO_OOP_IS_SMOOI(dom) && MOO_OOP_IS_SMOOI(type) && MOO_OOP_IS_SMOOI(proto));
+
+	fd = socket (MOO_OOP_TO_SMOOI(dom), MOO_OOP_TO_SMOOI(type), MOO_OOP_TO_SMOOI(proto));
+	if (fd == -1) 
+	{
+		errnum = moo_syserr_to_errnum(errno);
+		goto oops;
+	}
+
+	if (!MOO_IN_SMOOI_RANGE(fd))
+	{
+		/* the file descriptor is too big to be represented as a small integer */
+		errnum = MOO_ERANGE;
+		goto oops;
+	}
+
+	sck->handle = MOO_SMOOI_TO_OOP(fd);
+	MOO_STACK_SETRETTORCV (moo, nargs);
+
+	return MOO_PF_SUCCESS;
+
+oops:
+	if (fd >= 0) close (fd);
+	MOO_STACK_SETRETTOERROR (moo, nargs, errnum);
+	return MOO_PF_SUCCESS;
+}
+
+static moo_pfrc_t pf_close_socket (moo_t* moo, moo_ooi_t nargs)
+{
+	oop_sck_t sck;
+	int fd;
+
+	sck = (oop_sck_t)MOO_STACK_GETRCV(moo, nargs);
+	MOO_PF_CHECK_RCV (moo, 
+		MOO_OOP_IS_POINTER(sck) && 
+		MOO_OBJ_BYTESOF(sck) >= (MOO_SIZEOF(*sck) - MOO_SIZEOF(moo_obj_t)) &&
+		MOO_OOP_IS_SMOOI(sck->handle)
+	);
+
+	fd = MOO_OOP_TO_SMOOI(sck->handle);
+	if (fd >= 0)
+	{
+		if (close(MOO_OOP_TO_SMOOI(sck->handle)) == -1)
+		{
+			MOO_STACK_SETRETTOERROR (moo, nargs, moo_syserr_to_errnum(errno));
+			return MOO_PF_SUCCESS;
+		}
+		else
+		{
+			sck->handle = MOO_SMOOI_TO_OOP(-1);
+		}
+	}
+
+	MOO_STACK_SETRETTORCV (moo, nargs);
+	return MOO_PF_SUCCESS;
+}
+
+static moo_pfrc_t pf_connect (moo_t* moo, moo_ooi_t nargs)
+{
+	oop_sck_t sck;
+	int fd, oldfl, n;
+	moo_errnum_t errnum;
+
+	sck = (oop_sck_t)MOO_STACK_GETRCV(moo, nargs);
+	MOO_PF_CHECK_RCV (moo,
+		MOO_OOP_IS_POINTER(sck) &&
+		MOO_OBJ_BYTESOF(sck) >= (MOO_SIZEOF(*sck) - MOO_SIZEOF(moo_obj_t)) &&
+		MOO_OOP_IS_SMOOI(sck->handle));
+
+	fd = MOO_OOP_TO_SMOOI(sck->handle);
+
+	oldfl = fcntl(fd, F_GETFL, 0);
+	if (oldfl == -1 || fcntl(fd, F_SETFL, oldfl | O_NONBLOCK) == -1) goto oops_syserr;
+
+{
+
+struct sockaddr_in sin;
+memset (&sin, 0, sizeof(sin));
+sin.sin_family = AF_INET;
+sin.sin_addr.s_addr = inet_addr ("1.234.53.142");
+sin.sin_port = htons(80);
+	do
+	{
+		n = connect(fd, (struct sockaddr*)&sin, sizeof(sin));
+	}
+	while (n == -1 && errno == EINTR);
+}
+
+	if (n == -1 && errno != EINPROGRESS)
+	{
+		fcntl (fd, F_SETFL, oldfl);
+		goto oops_syserr;
+	}
+
+	MOO_STACK_SETRETTORCV (moo, nargs);
+	return MOO_PF_SUCCESS;
+
+oops_syserr:
+	errnum = moo_syserr_to_errnum(errno);
+
+oops:
+	MOO_STACK_SETRETTOERROR (moo, nargs, errnum);
+	return MOO_PF_SUCCESS;
+}
+/* ------------------------------------------------------------------------ */
+ 
+typedef struct fnctab_t fnctab_t;
+struct fnctab_t
+{
+	moo_method_type_t type;
+	moo_ooch_t mthname[15];
+	int variadic;
+	moo_pfimpl_t handler;
+};
+
+#define C MOO_METHOD_CLASS
+#define I MOO_METHOD_INSTANCE
+
+#define MA MOO_TYPE_MAX(moo_oow_t)
+
+static moo_pfinfo_t pfinfos[] =
+{
+	{ I, { '_','c','l','o','s','e','\0' },          0, { pf_close_socket,    0, 0  }  },
+	{ I, { '_','c','o','n','n','e','c','t','\0' },  0, { pf_connect,         3, 3  }  },
+	{ I, { '_','o','p','e','n','\0' },              0, { pf_open_socket,     3, 3  }  },
+};
+
+/* ------------------------------------------------------------------------ */
+
+static int import (moo_t* moo, moo_mod_t* mod, moo_oop_class_t _class)
+{
+	/*if (moo_setclasstrsize (moo, _class, MOO_SIZEOF(sck_t), MOO_NULL) <= -1) return -1;*/
+	return 0;
+}
+
+static moo_pfbase_t* query (moo_t* moo, moo_mod_t* mod, const moo_ooch_t* name, moo_oow_t namelen)
+{
+	return moo_findpfbase (moo, pfinfos, MOO_COUNTOF(pfinfos), name, namelen);
+}
+
+static void unload (moo_t* moo, moo_mod_t* mod)
+{
+	/* TODO: anything? close open open dll handles? For that, pf_open must store the value it returns to mod->ctx or somewhere..*/
+}
+
+int moo_mod_sck (moo_t* moo, moo_mod_t* mod)
+{
+	mod->import = import;
+	mod->query = query;
+	mod->unload = unload; 
+	mod->ctx = MOO_NULL;
+	return 0;
+}
diff --git a/moo/mod/stdio.c b/moo/mod/stdio.c
index 81ff27f..6136ead 100644
--- a/moo/mod/stdio.c
+++ b/moo/mod/stdio.c
@@ -75,7 +75,7 @@ static moo_pfrc_t pf_open (moo_t* moo, moo_ooi_t nargs)
 #endif
 	if (!stdio->fp) 
 	{
-		moo_seterrnum (moo, moo_syserrtoerrnum(errno));
+		moo_seterrnum (moo, moo_syserr_to_errnum(errno));
 		goto softfail;
 	}
 
@@ -157,7 +157,7 @@ static moo_pfrc_t __pf_puts (moo_t* moo, moo_ooi_t nargs, moo_oow_t limit)
 
 				if (fwrite (bcs, 1, bcslen, stdio->fp) < bcslen)
 				{
-					moo_seterrnum (moo, moo_syserrtoerrnum(errno));
+					moo_seterrnum (moo, moo_syserr_to_errnum(errno));
 					goto softfail;
 				}
 
@@ -169,8 +169,8 @@ static moo_pfrc_t __pf_puts (moo_t* moo, moo_ooi_t nargs, moo_oow_t limit)
 		puts_string:
 			if (fwrite (x->slot, 1, MOO_OBJ_GET_SIZE(x), stdio->fp) < MOO_OBJ_GET_SIZE(x))
 			{
-				moo_seterrnum (moo, moo_syserrtoerrnum(errno));
-				moo_seterrnum (moo, moo_syserrtoerrnum(errno));
+				moo_seterrnum (moo, moo_syserr_to_errnum(errno));
+				moo_seterrnum (moo, moo_syserr_to_errnum(errno));
 				goto softfail;
 			}
 		#endif
diff --git a/moo/mod/x11.c b/moo/mod/x11.c
index 38ff614..cb70e11 100644
--- a/moo/mod/x11.c
+++ b/moo/mod/x11.c
@@ -705,34 +705,39 @@ static moo_pfrc_t pf_draw_string (moo_t* moo, moo_ooi_t nargs)
 
 	if (MOO_OOP_IS_SMPTR(gc->font_set))
 	{
-		moo_oow_t ucslen, bcslen;
+		moo_oow_t bcslen;
 		moo_bch_t* bb;
 		int ascent = 10;
 		XRectangle r;
 
-		ucslen = MOO_OBJ_GET_SIZE(a3);
-		if (moo_convootobchars (moo, MOO_OBJ_GET_CHAR_SLOT(a3), &ucslen, MOO_NULL, &bcslen) <= -1 ||
+	#if defined(MOO_OOCH_IS_UCH)
+		moo_oow_t oocslen;
+
+		oocslen = MOO_OBJ_GET_SIZE(a3);
+		if (moo_convootobchars (moo, MOO_OBJ_GET_CHAR_SLOT(a3), &oocslen, MOO_NULL, &bcslen) <= -1 ||
 		    !(bb = moo_allocmem (moo, MOO_SIZEOF(moo_bch_t) * bcslen)))
 		{
 			MOO_DEBUG0 (moo, "<x11.draw_string> Error in converting a string\n");
 			MOO_STACK_SETRETTOERRNUM (moo, nargs);
 			return MOO_PF_SUCCESS;
 		}
-
-	//#if defined(MOO_OOCH_IS_UCH)
-		moo_convootobchars (moo, MOO_OBJ_GET_CHAR_SLOT(a3), &ucslen, bb, &bcslen);
-	//#else
-	//	moo_copybcstr (&bb->fn[parlen], bcslen + 1, arg->name);
-	//#endif
+		moo_convootobchars (moo, MOO_OBJ_GET_CHAR_SLOT(a3), &oocslen, bb, &bcslen);
+	#else
+		bb = MOO_OBJ_GET_CHAR_SLOT(a3);
+		bcslen = oocslen;
+	#endif
 
 		XmbTextExtents(MOO_OOP_TO_SMPTR(gc->font_set), bb, bcslen, MOO_NULL, &r);
 		ascent = r.height;
 
+		/* what about Xutf8DrawString? */
 		XmbDrawString (disp, (Window)MOO_OOP_TO_SMOOI(((oop_x11_widget_t)gc->widget)->window_handle), 
 			MOO_OOP_TO_SMPTR(gc->font_set), MOO_OOP_TO_SMPTR(gc->gc_handle), 
 			MOO_OOP_TO_SMOOI(a1), MOO_OOP_TO_SMOOI(a2) + ascent,  bb, bcslen);
 
+	#if defined(MOO_OOCH_IS_UCH)
 		moo_freemem (moo, bb);
+	#endif
 	}
 	else
 	{