diff --git a/include/cxx/cstring b/include/cxx/cstring
index 038080e75d0..68309195f07 100644
--- a/include/cxx/cstring
+++ b/include/cxx/cstring
@@ -57,6 +57,7 @@ namespace std
   using ::strdup;
   using ::strndup;
   using ::strerror;
+  using ::strerror_r;
   using ::strlen;
   using ::strnlen;
   using ::strcat;
diff --git a/include/string.h b/include/string.h
index 9ba3d03b028..92df7f85b5f 100644
--- a/include/string.h
+++ b/include/string.h
@@ -64,6 +64,7 @@ extern "C"
 FAR char  *strdup(FAR const char *s);
 FAR char  *strndup(FAR const char *s, size_t size);
 FAR const char *strerror(int);
+int        strerror_r(int, FAR char *, size_t);
 size_t     strlen(FAR const char *);
 size_t     strnlen(FAR const char *, size_t);
 FAR char  *strcat(FAR char *, FAR const char *);
@@ -71,9 +72,9 @@ FAR char  *strncat(FAR char *, FAR const char *, size_t);
 int        strcmp(FAR const char *, FAR const char *);
 int        strncmp(FAR const char *, FAR const char *, size_t);
 int        strcoll(FAR const char *, FAR const char *s2);
-FAR char  *strcpy(char *dest, FAR const char *src);
-FAR char  *stpcpy(char *dest, FAR const char *src);
-FAR char  *strncpy(char *, FAR const char *, size_t);
+FAR char  *strcpy(FAR char *dest, FAR const char *src);
+FAR char  *stpcpy(FAR char *dest, FAR const char *src);
+FAR char  *strncpy(FAR char *, FAR const char *, size_t);
 FAR char  *strpbrk(FAR const char *, FAR const char *);
 FAR char  *strchr(FAR const char *s, int c);
 FAR char  *strrchr(FAR const char *s, int c);
diff --git a/libc/libc.csv b/libc/libc.csv
index 46a193be2cc..fbb8512a583 100644
--- a/libc/libc.csv
+++ b/libc/libc.csv
@@ -154,6 +154,7 @@
 "strcspn","string.h","","size_t","FAR const char *","FAR const char *"
 "strdup","string.h","","FAR char","FAR const char *"
 "strerror","string.h","","FAR const char","int"
+"strerror_r","string.h","","int","int", "FAR char *", "size_t"
 "strftime","time.h","","size_t","FAR char *","size_t","FAR const char *","FAR const struct tm *"
 "strlen","string.h","","size_t","FAR const char *"
 "strncasecmp","strings.h","","int","FAR const char *","FAR const char *","size_t"
diff --git a/libc/string/Make.defs b/libc/string/Make.defs
index 415afc9237b..defedcfb60a 100644
--- a/libc/string/Make.defs
+++ b/libc/string/Make.defs
@@ -42,7 +42,7 @@ CSRCS += lib_strcpy.c lib_strcmp.c lib_strcspn.c lib_strdup.c
 CSRCS += lib_strerror.c lib_strlen.c lib_strnlen.c lib_strncasecmp.c
 CSRCS += lib_strncat.c lib_strncmp.c lib_strncpy.c lib_strndup.c
 CSRCS += lib_strcasestr.c lib_strpbrk.c lib_strrchr.c lib_strspn.c
-CSRCS += lib_strstr.c lib_strtok.c lib_strtokr.c
+CSRCS += lib_strstr.c lib_strtok.c lib_strtokr.c lib_strerrorr.c
 
 ifneq ($(CONFIG_LIBC_ARCH_MEMCPY),y)
 ifeq ($(CONFIG_MEMCPY_VIK),y)
diff --git a/libc/string/lib_strerrorr.c b/libc/string/lib_strerrorr.c
new file mode 100644
index 00000000000..5a19611e251
--- /dev/null
+++ b/libc/string/lib_strerrorr.c
@@ -0,0 +1,60 @@
+/****************************************************************************
+ * libc/string/lib_strerrorr.c
+ *
+ *   Copyright (C) 2017 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * 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.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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 <sys/types.h>
+#include <string.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: strerror_r
+ ****************************************************************************/
+
+int strerror_r(int errnum, FAR char *buf, size_t buflen)
+{
+  FAR const char *errstr = strerror(errnum);
+
+  DEBUGASSERT(buf != NULL);
+  strncpy(buf, errstr, buflen);
+  return OK;
+}