diff --git a/src/c/unicode/ucd_names_char.c b/src/c/unicode/ucd_names_char.c
index bb91bd841..0b42db64d 100644
--- a/src/c/unicode/ucd_names_char.c
+++ b/src/c/unicode/ucd_names_char.c
@@ -514,7 +514,7 @@ static void
 fill_pair_name(char *buffer, int pair)
 {
   if (pair < ECL_UCD_FIRST_PAIR) {
-    strncat(buffer, ecl_ucd_names_word[pair], ECL_UCD_LARGEST_CHAR_NAME+1);
+    strncat(buffer, ecl_ucd_names_word[pair], ECL_UCD_LARGEST_CHAR_NAME);
 /*
     printf("text=%s\n", ecl_ucd_names_word[pair]);
  */