Add override keyword when compiled with C++11 or later

source/utf8/checked.h

@@ -42,7 +42,7 @@ namespace utf8
         uint32_t cp;
     public:
         invalid_code_point(uint32_t codepoint) : cp(codepoint) {}
-        virtual const char* what() const throw() { return "Invalid code point"; }
+        virtual const char* what() const throw() OVERRIDE { return "Invalid code point"; }
         uint32_t code_point() const {return cp;}
     };
 
@@ -50,7 +50,7 @@ namespace utf8
         uint8_t u8;
     public:
         invalid_utf8 (uint8_t u) : u8(u) {}
-        virtual const char* what() const throw() { return "Invalid UTF-8"; }
+        virtual const char* what() const throw() OVERRIDE { return "Invalid UTF-8"; }
         uint8_t utf8_octet() const {return u8;}
     };
 
@@ -58,13 +58,13 @@ namespace utf8
         uint16_t u16;
     public:
         invalid_utf16 (uint16_t u) : u16(u) {}
-        virtual const char* what() const throw() { return "Invalid UTF-16"; }
+        virtual const char* what() const throw() OVERRIDE { return "Invalid UTF-16"; }
         uint16_t utf16_word() const {return u16;}
     };
 
     class not_enough_room : public exception {
     public:
-        virtual const char* what() const throw() { return "Not enough space"; }
+        virtual const char* what() const throw() OVERRIDE { return "Not enough space"; }
     };
 
     /// The library API - functions intended to be called by the users

source/utf8/core.h

@@ -38,6 +38,12 @@ DEALINGS IN THE SOFTWARE.
     #define UTF_CPP_CPLUSPLUS __cplusplus
 #endif
 
+#if UTF_CPP_CPLUSPLUS >= 201103L // C++ 11 or later
+    #define OVERRIDE override
+#else // C++ 98/03
+    #define OVERRIDE
+#endif // C++ 11 or later
+
 
 namespace utf8
 {