diff --git a/include/stdlib.h b/include/stdlib.h
index 6b4498ebea3..ddfcea74a81 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -42,8 +42,10 @@
 
 #include <nuttx/config.h>
 #include <nuttx/compiler.h>
+
 #include <sys/types.h>
 #include <stdint.h>
+#include <wchar.h>
 
 /****************************************************************************
  * Pre-processor Definitions
@@ -202,6 +204,13 @@ double_t  strtod(FAR const char *str, FAR char **endptr);
 
 FAR char *itoa(int val, FAR char *str, int base);
 
+/* Wide character operations */
+
+#ifdef CONFIG_LIBC_WCHAR
+int       mbtowc(FAR wchar_t *pwc, FAR const char *s, size_t n);
+int       wctomb(FAR char *s, wchar_t wchar);
+#endif
+
 /* Memory Management */
 
 FAR void *malloc(size_t);
diff --git a/include/wchar.h b/include/wchar.h
index 90e3d4f12ca..582cec46832 100644
--- a/include/wchar.h
+++ b/include/wchar.h
@@ -33,9 +33,6 @@
  *
  ****************************************************************************/
 
-#ifndef __INCLUDE_WCHAR_H
-#define __INCLUDE_WCHAR_H
-
 /****************************************************************************
  * Included Files
  ****************************************************************************/
@@ -50,6 +47,14 @@
 #include <stdio.h>
 #include <stddef.h>
 
+/* REVISIT: Moving the idempotence to this location resolves a circular
+ * dependency problem with stdlib.h which gets included indirectory and
+ * needs wchar_t.
+ */
+
+#ifndef __INCLUDE_WCHAR_H
+#define __INCLUDE_WCHAR_H
+
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
@@ -105,7 +110,6 @@ typedef int wint_t;
  *   state, the results are unspecified.
  */
 
-#if 0 /* Not used */
 /* Commented out because this is dangerous.  This defines a type that would
  * be internal to some wchar implementation.  NuttX does not implement the
  * wchar functions.  Having this definition is a time bomb:  If this header
@@ -127,7 +131,6 @@ struct mbstate_s
 };
 
 typedef struct mbstate_s mbstate_t;
-#endif
 
 /* FILE
  *   As described in <stdio.h>.
@@ -218,6 +221,8 @@ size_t            wcscspn(const wchar_t *, const wchar_t *);
 size_t            wcsftime(wchar_t *, size_t, const wchar_t *,
                       const struct tm *);
 size_t            wcslen(const wchar_t *);
+size_t            wcslcpy(FAR wchar_t *, FAR const wchar_t *, size_t);
+size_t            wcslcat(FAR wchar_t *, FAR const wchar_t *, size_t);
 wchar_t          *wcsncat(wchar_t *, const wchar_t *, size_t);
 int               wcsncmp(const wchar_t *, const wchar_t *, size_t);
 wchar_t          *wcsncpy(wchar_t *, const wchar_t *, size_t);
diff --git a/libc/locale/Make.defs b/libc/locale/Make.defs
index bbf9c6a33db..b59b7981455 100644
--- a/libc/locale/Make.defs
+++ b/libc/locale/Make.defs
@@ -37,7 +37,7 @@ ifeq ($(CONFIG_LIBC_LOCALE),y)
 
 # Add the locale files to the build
 
-CSRCS += lib_setlocale.c
+CSRCS += lib_setlocale.c lib_localeconv.c
 
 # Add the locale directory to the build
 
diff --git a/libc/locale/lib_localeconv.c b/libc/locale/lib_localeconv.c
index 3238dfa10a9..697f369cf45 100644
--- a/libc/locale/lib_localeconv.c
+++ b/libc/locale/lib_localeconv.c
@@ -60,7 +60,7 @@
  *
  ****************************************************************************/
 
-FAR struct lconv *localeconv(void);
+FAR struct lconv *localeconv(void)
 {
   /* NULL indicates the the locale was not changed */
 
diff --git a/libc/stdlib/Make.defs b/libc/stdlib/Make.defs
index 618b16a5450..22509d22dda 100644
--- a/libc/stdlib/Make.defs
+++ b/libc/stdlib/Make.defs
@@ -45,6 +45,10 @@ ifeq ($(CONFIG_FS_WRITABLE),y)
 CSRCS += lib_mktemp.c lib_mkstemp.c
 endif
 
+ifeq ($(CONFIG_LIBC_WCHAR),y)
+CSRCS += lib_mbtowc.c lib_wctomb.c
+endif
+
 ifeq ($(CONFIG_PSEUDOTERM_SUSV1),y)
 CSRCS += lib_ptsname.c lib_ptsnamer.c
 endif
diff --git a/libc/wchar/lib_mbtowc.c b/libc/stdlib/lib_mbtowc.c
similarity index 98%
rename from libc/wchar/lib_mbtowc.c
rename to libc/stdlib/lib_mbtowc.c
index aba6d55b56c..03b2b93d4eb 100644
--- a/libc/wchar/lib_mbtowc.c
+++ b/libc/stdlib/lib_mbtowc.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * libc/wchar/lib_mbtowc.c
+ * libc/stdlib/lib_mbtowc.c
  *
  *   Copyright (c)1999 Citrus Project,
  *   All rights reserved.
diff --git a/libc/wchar/lib_wctomb.c b/libc/stdlib/lib_wctomb.c
similarity index 98%
rename from libc/wchar/lib_wctomb.c
rename to libc/stdlib/lib_wctomb.c
index 0e865760638..cef60ad1495 100644
--- a/libc/wchar/lib_wctomb.c
+++ b/libc/stdlib/lib_wctomb.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * libc/wchar/lib_wctomb.c
+ * libc/stdlib/lib_wctomb.c
  *
  * This code is derived from software contributed to Berkeley by
  * Chris Torek.
@@ -35,9 +35,10 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
-#include <wchar.h>
+
 #include <string.h>
 #include <stdlib.h>
+#include <wchar.h>
 #include <errno.h>
 
 #ifdef CONFIG_LIBC_WCHAR
diff --git a/libc/wchar/Make.defs b/libc/wchar/Make.defs
index 4ec911e7b98..f6788f592de 100644
--- a/libc/wchar/Make.defs
+++ b/libc/wchar/Make.defs
@@ -38,9 +38,8 @@ ifeq ($(CONFIG_LIBC_WCHAR),y)
 # Add the internal C files to the build
 
 CSRCS += lib_wcscmp.c lib_wcslen.c lib_wmemchr.c lib_wmemcmp.c lib_wmemcpy.c
-CSRCS += lib_wmemmove.c lib_wmemset.c lib_mbtowc.c lib_btowc.c lib_mbrtowc.c
-CSRCS += lib_wctomb.c lib_wctob.c lib_wcslcpy.c lib_wcsxfrm.c lib_wctype.c
-CSRCS += lib_wcrtomb.c
+CSRCS += lib_wmemmove.c lib_wmemset.c lib_btowc.c lib_mbrtowc.c lib_wctob.c
+CSRCS +=lib_wcslcpy.c lib_wcsxfrm.c lib_wcrtomb.c
 
 # Add the wchar directory to the build
 
diff --git a/libc/wchar/lib_btowc.c b/libc/wchar/lib_btowc.c
index 066ed654ccb..069a4dc9c4d 100644
--- a/libc/wchar/lib_btowc.c
+++ b/libc/wchar/lib_btowc.c
@@ -33,10 +33,11 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
-#include <wchar.h>
+
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <wchar.h>
 
 #ifdef CONFIG_LIBC_WCHAR
 
@@ -54,18 +55,18 @@
 
 wint_t btowc(int c)
 {
-  int retval = 0;
   wchar_t pwc;
-  unsigned char b;
+  char b;
+  int retval = 0;
 
   if (c == EOF)
     {
       return WEOF;
     }
 
-  b = (unsigned char)c;
+  b = (char)c;
 
-  retval = mbtowc(&pwc, &b, 1);
+  retval = mbtowc(&pwc, (FAR const char *)&b, 1);
 
   if (retval != 0 && retval != 1)
     {
diff --git a/libc/wchar/lib_mbrtowc.c b/libc/wchar/lib_mbrtowc.c
index a1f3ee765cd..f82ff1808a1 100644
--- a/libc/wchar/lib_mbrtowc.c
+++ b/libc/wchar/lib_mbrtowc.c
@@ -33,11 +33,12 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
-#include <wchar.h>
+
 #include <stdlib.h>
 #include <stdio.h>
 #include <errno.h>
 #include <string.h>
+#include <wchar.h>
 
 #ifdef CONFIG_LIBC_WCHAR
 
@@ -68,11 +69,11 @@ size_t mbrtowc(FAR wchar_t *pwc, FAR const char *s, size_t n, mbstate_t *ps)
 
   if (retval == -1)
     {
-      return (size_t) (-1);
+      return (size_t)(-1);
     }
   else
     {
-      return (size_t) retval;
+      return (size_t)retval;
     }
 }
 #endif
diff --git a/libc/wchar/lib_wcsxfrm.c b/libc/wchar/lib_wcsxfrm.c
index 2ecad451394..303a540b322 100644
--- a/libc/wchar/lib_wcsxfrm.c
+++ b/libc/wchar/lib_wcsxfrm.c
@@ -32,6 +32,7 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
+
 #include <string.h>
 #include <wchar.h>
 
diff --git a/libc/wchar/lib_wctob.c b/libc/wchar/lib_wctob.c
index 75290974e07..1808bf9e0da 100644
--- a/libc/wchar/lib_wctob.c
+++ b/libc/wchar/lib_wctob.c
@@ -35,9 +35,11 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
-#include <wchar.h>
+
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
+#include <wchar.h>
 #include <limits.h>
 
 #ifdef CONFIG_LIBC_WCHAR