diff --git a/src/locale.cpp b/src/locale.cpp
index 089fae6a3..109629d64 100644
--- a/src/locale.cpp
+++ b/src/locale.cpp
@@ -940,6 +940,7 @@ ctype<char>::classic_table()  _NOEXCEPT
 #else
     // Platform not supported: abort so the person doing the port knows what to
     // fix
+# warning  ctype<char>::classic_table() is not implemented
     abort();
     return NULL;
 #endif