diff --git a/Data/UnixTime/Sys.hsc b/Data/UnixTime/Sys.hsc
--- a/Data/UnixTime/Sys.hsc
+++ b/Data/UnixTime/Sys.hsc
@@ -26,6 +26,4 @@
 getUnixTime :: IO UnixTime
 getUnixTime = allocaBytes (#const sizeof(struct timeval)) $ \ p_timeval -> do
     throwErrnoIfMinus1_ "getClockTime" $ c_gettimeofday p_timeval nullPtr
-    sec  <- (#peek struct timeval,tv_sec)  p_timeval
-    usec <- (#peek struct timeval,tv_usec) p_timeval
-    return $ UnixTime sec usec
+    peek (castPtr p_timeval)
diff --git a/cbits/config.h.in b/cbits/config.h.in
--- a/cbits/config.h.in
+++ b/cbits/config.h.in
@@ -21,6 +21,12 @@
 /* Define to 1 if you have the `strptime_l' function. */
 #undef HAVE_STRPTIME_L
 
+/* Define to 1 if you have the `strtoll_l' function. */
+#undef HAVE_STRTOLL_L
+
+/* Define to 1 if you have the `strtol_l' function. */
+#undef HAVE_STRTOL_L
+
 /* Define to 1 if you have the <sys/stat.h> header file. */
 #undef HAVE_SYS_STAT_H
 
@@ -30,26 +36,38 @@
 /* Define to 1 if you have the `timegm' function. */
 #undef HAVE_TIMEGM
 
-/* Define to 1 if you have the `_mkgmtime' function. */
-#undef HAVE__MKGMTIME
+/* Define to 1 if you have the <unistd.h> header file. */
+#undef HAVE_UNISTD_H
 
+/* Define to 1 if you have the <xlocale.h> header file. */
+#undef HAVE_XLOCALE_H
+
+/* Define to 1 if you have the `_create_locale' function. */
+#undef HAVE__CREATE_LOCALE
+
 /* Define to 1 if you have the `_get_current_locale' function. */
 #undef HAVE__GET_CURRENT_LOCALE
 
-/* Define to 1 if you have the `strtol_l' function. */
-#undef HAVE_STRTOL_L
+/* Define to 1 if you have the `_isblank_l' function. */
+#undef HAVE__ISBLANK_L
 
-/* Define to 1 if you have the `strtoll_l' function. */
-#undef HAVE_STRTOLL_L
+/* Define to 1 if you have the `_isdigit_l' function. */
+#undef HAVE__ISDIGIT_L
 
-/* Define to 1 if you have the <unistd.h> header file. */
-#undef HAVE_UNISTD_H
+/* Define to 1 if you have the `_isspace_l' function. */
+#undef HAVE__ISSPACE_L
 
-/* Define to 1 if you have the <xlocale.h> header file. */
-#undef HAVE_XLOCALE_H
+/* Define to 1 if you have the `_isupper_l' function. */
+#undef HAVE__ISUPPER_L
 
+/* Define to 1 if you have the `_mkgmtime' function. */
+#undef HAVE__MKGMTIME
+
 /* "Is Linux" */
 #undef IS_LINUX
+
+/* "Is Windows NT 6.1" */
+#undef IS_NT61
 
 /* Define to the address where bug reports for this package should be sent. */
 #undef PACKAGE_BUGREPORT
diff --git a/cbits/strftime.c b/cbits/strftime.c
--- a/cbits/strftime.c
+++ b/cbits/strftime.c
@@ -112,8 +112,11 @@
 {
 #if HAVE__GET_CURRENT_LOCALE
 	return _patch_strftime_l(s, maxsize, format, t, _get_current_locale());
-#else
+#elif HAVE__CREATE_LOCALE && !IS_NT61
 	return _patch_strftime_l(s, maxsize, format, t, _create_locale(LC_TIME, "C"));
+#else
+	_locale_t locale;
+	return _patch_strftime_l(s, maxsize, format, t, locale);
 #endif
 }
 
diff --git a/cbits/strptime.c b/cbits/strptime.c
--- a/cbits/strptime.c
+++ b/cbits/strptime.c
@@ -712,7 +712,10 @@
 {
 #if HAVE__GET_CURRENT_LOCALE
 	return strptime_l(buf, fmt, tm, _get_current_locale());
-#else
+#elif HAVE__CREATE_LOCALE && !IS_NT61
 	return strptime_l(buf, fmt, tm, _create_locale(LC_TIME, "C"));
+#else
+	_locale_t locale;
+	return strptime_l(buf, fmt, tm, locale);
 #endif
 }
diff --git a/cbits/win_patch.c b/cbits/win_patch.c
--- a/cbits/win_patch.c
+++ b/cbits/win_patch.c
@@ -12,10 +12,12 @@
 }
 #endif
 
+#if !HAVE__ISBLANK_L
 inline int isblank_l( int c, _locale_t _loc)
 {
     return ( c == ' ' || c == '\t' );
 }
+#endif
 
 inline int strncasecmp_l(const char *s1, const char *s2, int len, _locale_t _loc) {
     return strncasecmp(s1, s2, len);
diff --git a/cbits/win_patch.h b/cbits/win_patch.h
--- a/cbits/win_patch.h
+++ b/cbits/win_patch.h
@@ -81,9 +81,23 @@
     1 + TYPE_SIGNED(type))
 #endif /* !defined INT_STRLEN_MAXIMUM */
 
+#if HAVE__ISSPACE_L
 #define isspace_l _isspace_l
+#else
+#define isspace_l(ch, locale) isspace(ch)
+#endif
+
+#if HAVE__ISUPPER_L
 #define isupper_l _isupper_l
+#else
+#define isupper_l(ch, locale) isupper(ch)
+#endif
+
+#if HAVE__ISDIGIT_L
 #define isdigit_l _isdigit_l
+#else
+#define isdigit_l(ch, locale) isdigit(ch)
+#endif
 
 #if !HAVE_STRTOL_L
 long strtol_l(const char *nptr, char **endptr, int base, _locale_t locale);
@@ -102,7 +116,9 @@
 #define isleap_sum(a, b)    isleap((a) % 400 + (b) % 400)
 #endif /* !defined isleap_sum */
 
+#if !HAVE__ISBLANK_L
 int isblank_l( int c, _locale_t _loc);
+#endif
 
 int strncasecmp_l(const char *s1, const char *s2, int len, _locale_t _loc);
 
diff --git a/configure b/configure
--- a/configure
+++ b/configure
@@ -3326,6 +3326,17 @@
 fi
 done
 
+for ac_func in _create_locale
+do :
+  ac_fn_c_check_func "$LINENO" "_create_locale" "ac_cv_func__create_locale"
+if test "x$ac_cv_func__create_locale" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE__CREATE_LOCALE 1
+_ACEOF
+
+fi
+done
+
 for ac_func in strtol_l
 do :
   ac_fn_c_check_func "$LINENO" "strtol_l" "ac_cv_func_strtol_l"
@@ -3348,7 +3359,51 @@
 fi
 done
 
+for ac_func in _isspace_l
+do :
+  ac_fn_c_check_func "$LINENO" "_isspace_l" "ac_cv_func__isspace_l"
+if test "x$ac_cv_func__isspace_l" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE__ISSPACE_L 1
+_ACEOF
 
+fi
+done
+
+for ac_func in _isupper_l
+do :
+  ac_fn_c_check_func "$LINENO" "_isupper_l" "ac_cv_func__isupper_l"
+if test "x$ac_cv_func__isupper_l" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE__ISUPPER_L 1
+_ACEOF
+
+fi
+done
+
+for ac_func in _isdigit_l
+do :
+  ac_fn_c_check_func "$LINENO" "_isdigit_l" "ac_cv_func__isdigit_l"
+if test "x$ac_cv_func__isdigit_l" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE__ISDIGIT_L 1
+_ACEOF
+
+fi
+done
+
+for ac_func in _isblank_l
+do :
+  ac_fn_c_check_func "$LINENO" "_isblank_l" "ac_cv_func__isblank_l"
+if test "x$ac_cv_func__isblank_l" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE__ISBLANK_L 1
+_ACEOF
+
+fi
+done
+
+
 host=`uname -a`
 case $host in
   Linux*)
@@ -3363,6 +3418,22 @@
 cat >>confdefs.h <<_ACEOF
 #define IS_LINUX $LINUX
 _ACEOF
+
+
+case $host in
+  MINGW??_NT-6.1*)
+	NT61=1
+	;;
+  *)
+	NT61=0
+	;;
+esac
+
+
+cat >>confdefs.h <<_ACEOF
+#define IS_NT61 $NT61
+_ACEOF
+
 
 cat >confcache <<\_ACEOF
 # This file is a shell script that caches the results of configure
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -10,8 +10,13 @@
 AC_CHECK_FUNCS(timegm)
 AC_CHECK_FUNCS(_mkgmtime)
 AC_CHECK_FUNCS(_get_current_locale)
+AC_CHECK_FUNCS(_create_locale)
 AC_CHECK_FUNCS(strtol_l)
 AC_CHECK_FUNCS(strtoll_l)
+AC_CHECK_FUNCS(_isspace_l)
+AC_CHECK_FUNCS(_isupper_l)
+AC_CHECK_FUNCS(_isdigit_l)
+AC_CHECK_FUNCS(_isblank_l)
 
 host=`uname -a`
 case $host in
@@ -24,4 +29,16 @@
 esac
 
 AC_DEFINE_UNQUOTED(IS_LINUX,$LINUX,"Is Linux")
+
+case $host in
+  MINGW??_NT-6.1*)
+	NT61=1
+	;;
+  *)
+	NT61=0
+	;;
+esac
+
+AC_DEFINE_UNQUOTED(IS_NT61,$NT61,"Is Windows NT 6.1")
+
 AC_OUTPUT
diff --git a/unix-time.cabal b/unix-time.cabal
--- a/unix-time.cabal
+++ b/unix-time.cabal
@@ -1,5 +1,5 @@
 Name:                   unix-time
-Version:                0.4.5
+Version:                0.4.6
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             Kazu Yamamoto <kazu@iij.ad.jp>
 License:                BSD3