diff --git a/include/cxx/cwchar b/include/cxx/cwchar
index b33b0477b8..813f4cde9c 100755
--- a/include/cxx/cwchar
+++ b/include/cxx/cwchar
@@ -113,6 +113,7 @@ namespace std
   using ::wcstod;
   using ::wcstok;
   using ::wcstol;
+  using ::wcstoll;
   using ::wcstoul;
   using ::wcswcs;
   using ::wcswidth;
diff --git a/include/wchar.h b/include/wchar.h
index 11cad2415b..295886ef70 100644
--- a/include/wchar.h
+++ b/include/wchar.h
@@ -217,6 +217,7 @@ FAR wchar_t      *wcsstr(FAR const wchar_t *, FAR const wchar_t *);
 double            wcstod(FAR const wchar_t *, FAR wchar_t **);
 FAR wchar_t      *wcstok(FAR wchar_t *, FAR const wchar_t *, FAR wchar_t **);
 long int          wcstol(FAR const wchar_t *, FAR wchar_t **, int);
+long long int     wcstoll(FAR const wchar_t *, FAR wchar_t **, int);
 unsigned long int wcstoul(FAR const wchar_t *, FAR wchar_t **, int);
 FAR wchar_t      *wcswcs(FAR const wchar_t *, FAR const wchar_t *);
 int               wcswidth(FAR const wchar_t *, size_t);
diff --git a/libc/libc.csv b/libc/libc.csv
index fbb8512a58..3907815f30 100644
--- a/libc/libc.csv
+++ b/libc/libc.csv
@@ -202,6 +202,7 @@
 "wcsftime","wchar.h","defined(CONFIG_LIBC_WCHAR)","size_t", "FAR wchar_t *", "size_t", "FAR const wchar_t *", "FAR const struct tm *"
 "wcslcpy","wchar.h","defined(CONFIG_LIBC_WCHAR)","size_t","FAR const wchar_t *","FAR const wchar_t *","size_t"
 "wcslen","wchar.h","defined(CONFIG_LIBC_WCHAR)","size_t","FAR const wchar_t *"
+"wcstoll", "wchar.h", "defined(CONFIG_LIBC_WCHAR)", "long long int", "FAR const wchar_t *", "FAR wchar_t **", "int"
 "wcsxfrm","wchar.h","defined(CONFIG_LIBC_WCHAR)","size_t","wchar_t *","FAR const wchar_t *","size_t"
 "wctob","wchar.h","defined(CONFIG_LIBC_WCHAR)","int","wchar_t"
 "wctomb","wchar.h","defined(CONFIG_LIBC_WCHAR)","int","FAR char *","wchar_t"
diff --git a/libc/string/lib_strerrorr.c b/libc/string/lib_strerrorr.c
index 5a19611e25..995825b137 100644
--- a/libc/string/lib_strerrorr.c
+++ b/libc/string/lib_strerrorr.c
@@ -41,6 +41,7 @@
 
 #include <sys/types.h>
 #include <string.h>
+#include <assert.h>
 
 /****************************************************************************
  * Public Functions
diff --git a/libc/wchar/Make.defs b/libc/wchar/Make.defs
index dbede3342a..462a72412f 100644
--- a/libc/wchar/Make.defs
+++ b/libc/wchar/Make.defs
@@ -40,7 +40,7 @@ ifeq ($(CONFIG_LIBC_WCHAR),y)
 CSRCS += lib_wcscmp.c lib_wcslen.c lib_wmemchr.c lib_wmemcmp.c
 CSRCS += lib_wmemcpy.c lib_wmemmove.c lib_wmemset.c lib_btowc.c
 CSRCS += lib_mbrtowc.c lib_wctob.c lib_wcslcpy.c lib_wcsxfrm.c
-CSRCS += lib_wcrtomb.c lib_wcsftime.c lib_wcscoll.c
+CSRCS += lib_wcrtomb.c lib_wcsftime.c lib_wcscoll.c lib_wcstoll.c
 
 # Add the wchar directory to the build
 
diff --git a/libc/wchar/lib_wcstoll.c b/libc/wchar/lib_wcstoll.c
new file mode 100644
index 0000000000..150f02aaa9
--- /dev/null
+++ b/libc/wchar/lib_wcstoll.c
@@ -0,0 +1,60 @@
+/****************************************************************************
+ * libc/wchar/lib_wcstoll.c
+ *
+ *   Copyright (c)1999 Citrus Project,
+ *   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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdlib.h>
+#include <wchar.h>
+
+#ifdef CONFIG_LIBC_WCHAR
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: wcstoll
+ *
+ * Description:
+ *   The wcstoll() function is the wide-character equivalent of the strtoll()
+ *   function.  It converts a wchar string to long long value.
+ *
+ ****************************************************************************/
+
+long long int wcstoll(FAR const wchar_t *nptr, FAR wchar_t **endptr, int base)
+{
+  return strtoll((FAR const char *)nptr, (FAR char **)endptr, base);
+}
+
+#endif /* CONFIG_LIBC_WCHAR */