diff --git a/sql/item_func.cc b/sql/item_func.cc
index bef48b1bfed..67fe15a7f0d 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -3351,8 +3351,12 @@ bool udf_handler::get_arguments()
 	{
 	  f_args.args[i]=    (char*) res->ptr();
 	  f_args.lengths[i]= res->length();
-	  break;
 	}
+	else
+	{
+	  f_args.lengths[i]= 0;
+	}
+	break;
       }
     case INT_RESULT:
       *((longlong*) to) = args[i]->val_int();
diff --git a/sql/udf_example.c b/sql/udf_example.c
index bfd153b7d28..af625b7ebf0 100644
--- a/sql/udf_example.c
+++ b/sql/udf_example.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+/* Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -295,9 +295,20 @@ char *metaphon(UDF_INIT *initid __attribute__((unused)),
 
   if (!word)					/* Null argument */
   {
+    /* The length is expected to be zero when the argument is NULL. */
+    assert(args->lengths[0] == 0);
     *is_null=1;
     return 0;
   }
+  else
+  {
+    /*
+      A check to confirm that argument length has the value it is
+      expected to have.
+    */
+    assert(strlen(word) == args->lengths[0]);
+  }
+
   w_end=word+args->lengths[0];
   org_result=result;