diff --git a/include/ctype.h b/include/ctype.h
index 9b9463f336..a24231030c 100644
--- a/include/ctype.h
+++ b/include/ctype.h
@@ -31,26 +31,7 @@
  ****************************************************************************/
 
 #include <nuttx/compiler.h>
-
-/****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
-
-#define isalnum_l(c, l)  isalnum(c)
-#define isalpha_l(c, l)  isalpha(c)
-#define isascii_l(c, l)  isascii(c)
-#define isblank_l(c, l)  isblank(c)
-#define iscntrl_l(c, l)  iscntrl(c)
-#define isdigit_l(c, l)  isdigit(c)
-#define isgraph_l(c, l)  isgraph(c)
-#define islower_l(c, l)  islower(c)
-#define isprint_l(c, l)  isprint(c)
-#define ispunct_l(c, l)  ispunct(c)
-#define isspace_l(c, l)  isspace(c)
-#define isupper_l(c, l)  isupper(c)
-#define isxdigit_l(c, l) isxdigit(c)
-#define tolower_l(c, l)  tolower(c)
-#define toupper_l(c, l)  toupper(c)
+#include <langinfo.h>
 
 /****************************************************************************
  * Inline Functions
@@ -80,8 +61,14 @@ static inline int isspace(int c)
   return c == ' ' || c == '\t' || c == '\n' || c == '\r' ||
          c == '\f' || c == '\v';
 }
+
+static inline int isspace_l(int c, locale_t locale)
+{
+  return isspace(c);
+}
 #else
 int isspace(int c);
+int isspace_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -98,8 +85,14 @@ static inline int isascii(int c)
 {
   return c >= 0 && c <= 0x7f;
 }
+
+static inline int isascii_l(int c, locale_t locale)
+{
+  return isascii(c);
+}
 #else
 int isascii(int c);
+int isascii_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -115,8 +108,14 @@ static inline int isprint(int c)
 {
   return c >= 0x20 && c < 0x7f;
 }
+
+static inline int isprint_l(int c, locale_t locale)
+{
+  return isprint(c);
+}
 #else
 int isprint(int c);
+int isprint_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -132,8 +131,14 @@ static inline int isgraph(int c)
 {
   return c > 0x20 && c < 0x7f;
 }
+
+static inline int isgraph_l(int c, locale_t locale)
+{
+  return isgraph(c);
+}
 #else
 int isgraph(int c);
+int isgraph_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -149,8 +154,14 @@ static inline int iscntrl(int c)
 {
   return c < 0x20 || c == 0x7f;
 }
+
+static inline int iscntrl_l(int c, locale_t locale)
+{
+  return iscntrl(c);
+}
 #else
 int iscntrl(int c);
+int iscntrl_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -166,8 +177,14 @@ static inline int islower(int c)
 {
   return c >= 'a' && c <= 'z';
 }
+
+static inline int islower_l(int c, locale_t locale)
+{
+  return islower(c);
+}
 #else
 int islower(int c);
+int islower_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -183,8 +200,14 @@ static inline int isupper(int c)
 {
   return c >= 'A' && c <= 'Z';
 }
+
+static inline int isupper_l(int c, locale_t locale)
+{
+  return isupper(c);
+}
 #else
 int isupper(int c);
+int isupper_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -200,8 +223,14 @@ static inline int isalpha(int c)
 {
   return islower(c) || isupper(c);
 }
+
+static inline int isalpha_l(int c, locale_t locale)
+{
+  return isalpha(c);
+}
 #else
 int isalpha(int c);
+int isalpha_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -217,8 +246,14 @@ static inline int isblank(int c)
 {
   return c == ' ' || c == '\t';
 }
+
+static inline int isblank_l(int c, locale_t locale)
+{
+  return isblank(c);
+}
 #else
 int isblank(int c);
+int isblank_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -234,8 +269,14 @@ static inline int isdigit(int c)
 {
   return c >= '0' && c <= '9';
 }
+
+static inline int isdigit_l(int c, locale_t locale)
+{
+  return isdigit(c);
+}
 #else
 int isdigit(int c);
+int isdigit_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -251,8 +292,14 @@ static inline int isalnum(int c)
 {
   return isalpha(c) || isdigit(c);
 }
+
+static inline int isalnum_l(int c, locale_t locale)
+{
+  return isalnum(c);
+}
 #else
 int isalnum(int c);
+int isalnum_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -269,8 +316,14 @@ static inline int ispunct(int c)
 {
   return isgraph(c) && !isalnum(c);
 }
+
+static inline int ispunct_l(int c, locale_t locale)
+{
+  return ispunct(c);
+}
 #else
 int ispunct(int c);
+int ispunct_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -288,8 +341,14 @@ static inline int isxdigit(int c)
          (c >= 'a' && c <= 'f') ||
          (c >= 'A' && c <= 'F');
 }
+
+static inline int isxdigit_l(int c, locale_t locale)
+{
+  return isxdigit(c);
+}
 #else
 int isxdigit(int c);
+int isxdigit_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -305,8 +364,14 @@ static inline int toupper(int c)
 {
   return (c >= 'a' && c <= 'z') ? c - 'a' + 'A' : c;
 }
+
+static inline int toupper_l(int c, locale_t locale)
+{
+  return toupper(c);
+}
 #else
 int toupper(int c);
+int toupper_l(int c, locale_t locale);
 #endif
 
 /****************************************************************************
@@ -322,8 +387,14 @@ static inline int tolower(int c)
 {
   return (c >= 'A' && c <= 'Z') ? (c - 'A' + 'a') : c;
 }
+
+static inline int tolower_l(int c, locale_t locale)
+{
+  return tolower(c);
+}
 #else
 int tolower(int c);
+int tolower_l(int c, locale_t locale);
 #endif
 
 #undef EXTERN
diff --git a/libs/libc/ctype/lib_isalnum.c b/libs/libc/ctype/lib_isalnum.c
index cc113a94d3..64eaa83d54 100644
--- a/libs/libc/ctype/lib_isalnum.c
+++ b/libs/libc/ctype/lib_isalnum.c
@@ -32,3 +32,8 @@ int isalnum(int c)
 {
   return isalpha(c) || isdigit(c);
 }
+
+int isalnum_l(int c, locale_t locale)
+{
+  return isalnum(c);
+}
diff --git a/libs/libc/ctype/lib_isalpha.c b/libs/libc/ctype/lib_isalpha.c
index ba86844f51..d1065649d9 100644
--- a/libs/libc/ctype/lib_isalpha.c
+++ b/libs/libc/ctype/lib_isalpha.c
@@ -32,3 +32,8 @@ int isalpha(int c)
 {
   return islower(c) || isupper(c);
 }
+
+int isalpha_l(int c, locale_t locale)
+{
+  return isalpha(c);
+}
diff --git a/libs/libc/ctype/lib_isascii.c b/libs/libc/ctype/lib_isascii.c
index 2be59c1839..c1db283f71 100644
--- a/libs/libc/ctype/lib_isascii.c
+++ b/libs/libc/ctype/lib_isascii.c
@@ -32,3 +32,8 @@ int isascii(int c)
 {
   return c >= 0 && c <= 0x7f;
 }
+
+int isascii_l(int c, locale_t locale)
+{
+  return isascii(c);
+}
diff --git a/libs/libc/ctype/lib_isblank.c b/libs/libc/ctype/lib_isblank.c
index 846cbcf933..b1e206ddd5 100644
--- a/libs/libc/ctype/lib_isblank.c
+++ b/libs/libc/ctype/lib_isblank.c
@@ -32,3 +32,8 @@ int isblank(int c)
 {
   return c == ' ' || c == '\t';
 }
+
+int isblank_l(int c, locale_t locale)
+{
+  return isblank(c);
+}
diff --git a/libs/libc/ctype/lib_iscntrl.c b/libs/libc/ctype/lib_iscntrl.c
index 697b3d4829..5800c51759 100644
--- a/libs/libc/ctype/lib_iscntrl.c
+++ b/libs/libc/ctype/lib_iscntrl.c
@@ -32,3 +32,8 @@ int iscntrl(int c)
 {
   return c < 0x20 || c == 0x7f;
 }
+
+int iscntrl_l(int c, locale_t locale)
+{
+  return iscntrl(c);
+}
diff --git a/libs/libc/ctype/lib_isdigit.c b/libs/libc/ctype/lib_isdigit.c
index 8656913dab..69926f6fd6 100644
--- a/libs/libc/ctype/lib_isdigit.c
+++ b/libs/libc/ctype/lib_isdigit.c
@@ -32,3 +32,8 @@ int isdigit(int c)
 {
   return c >= '0' && c <= '9';
 }
+
+int isdigit_l(int c, locale_t locale)
+{
+  return isdigit(c);
+}
diff --git a/libs/libc/ctype/lib_isgraph.c b/libs/libc/ctype/lib_isgraph.c
index 9dfa1f63ae..b6825a8b0d 100644
--- a/libs/libc/ctype/lib_isgraph.c
+++ b/libs/libc/ctype/lib_isgraph.c
@@ -32,3 +32,8 @@ int isgraph(int c)
 {
   return c > 0x20 && c < 0x7f;
 }
+
+int isgraph_l(int c, locale_t locale)
+{
+  return isgraph(c);
+}
diff --git a/libs/libc/ctype/lib_islower.c b/libs/libc/ctype/lib_islower.c
index aca5ae2742..9fcec04555 100644
--- a/libs/libc/ctype/lib_islower.c
+++ b/libs/libc/ctype/lib_islower.c
@@ -32,3 +32,8 @@ int islower(int c)
 {
   return c >= 'a' && c <= 'z';
 }
+
+int islower_l(int c, locale_t locale)
+{
+  return islower(c);
+}
diff --git a/libs/libc/ctype/lib_isprint.c b/libs/libc/ctype/lib_isprint.c
index 6a4b578db7..0c7c2afaa5 100644
--- a/libs/libc/ctype/lib_isprint.c
+++ b/libs/libc/ctype/lib_isprint.c
@@ -32,3 +32,8 @@ int isprint(int c)
 {
   return c >= 0x20 && c < 0x7f;
 }
+
+int isprint_l(int c, locale_t locale)
+{
+  return isprint(c);
+}
diff --git a/libs/libc/ctype/lib_ispunct.c b/libs/libc/ctype/lib_ispunct.c
index 88011c2833..5139b087a1 100644
--- a/libs/libc/ctype/lib_ispunct.c
+++ b/libs/libc/ctype/lib_ispunct.c
@@ -32,3 +32,8 @@ int ispunct(int c)
 {
   return isgraph(c) && !isalnum(c);
 }
+
+int ispunct_l(int c, locale_t locale)
+{
+  return ispunct(c);
+}
diff --git a/libs/libc/ctype/lib_isspace.c b/libs/libc/ctype/lib_isspace.c
index ed2616213e..699c493930 100644
--- a/libs/libc/ctype/lib_isspace.c
+++ b/libs/libc/ctype/lib_isspace.c
@@ -33,3 +33,8 @@ int isspace(int c)
   return c == ' ' || c == '\t' || c == '\n' || c == '\r' ||
          c == '\f' || c == '\v';
 }
+
+int isspace_l(int c, locale_t locale)
+{
+  return isspace(c);
+}
diff --git a/libs/libc/ctype/lib_isupper.c b/libs/libc/ctype/lib_isupper.c
index 5c7f51caae..56796c322f 100644
--- a/libs/libc/ctype/lib_isupper.c
+++ b/libs/libc/ctype/lib_isupper.c
@@ -32,3 +32,8 @@ int isupper(int c)
 {
   return c >= 'A' && c <= 'Z';
 }
+
+int isupper_l(int c, locale_t locale)
+{
+  return isupper(c);
+}
diff --git a/libs/libc/ctype/lib_isxdigit.c b/libs/libc/ctype/lib_isxdigit.c
index d5ae6dcfbe..6187358ecc 100644
--- a/libs/libc/ctype/lib_isxdigit.c
+++ b/libs/libc/ctype/lib_isxdigit.c
@@ -34,3 +34,8 @@ int isxdigit(int c)
          (c >= 'a' && c <= 'f') ||
          (c >= 'A' && c <= 'F');
 }
+
+int isxdigit_l(int c, locale_t locale)
+{
+  return isxdigit(c);
+}
diff --git a/libs/libc/ctype/lib_tolower.c b/libs/libc/ctype/lib_tolower.c
index 74f5c98eb7..d65ac4e364 100644
--- a/libs/libc/ctype/lib_tolower.c
+++ b/libs/libc/ctype/lib_tolower.c
@@ -32,3 +32,8 @@ int tolower(int c)
 {
   return (c >= 'A' && c <= 'Z') ? (c - 'A' + 'a') : c;
 }
+
+int tolower_l(int c, locale_t locale)
+{
+  return tolower(c);
+}
diff --git a/libs/libc/ctype/lib_toupper.c b/libs/libc/ctype/lib_toupper.c
index d9f0c8eb4b..7cd5ba0e26 100644
--- a/libs/libc/ctype/lib_toupper.c
+++ b/libs/libc/ctype/lib_toupper.c
@@ -32,3 +32,9 @@ int toupper(int c)
 {
   return (c >= 'a' && c <= 'z') ? c - 'a' + 'A' : c;
 }
+
+int toupper_l(int c, locale_t locale)
+{
+  return toupper(c);
+}
+