diff --git a/ext/ereg/regex/cname.h b/ext/ereg/regex/cname.h
index 670b2738828..c2855dad5d1 100644
--- a/ext/ereg/regex/cname.h
+++ b/ext/ereg/regex/cname.h
@@ -1,6 +1,6 @@
 /* character-name table */
-static struct cname {
-	char *name;
+static const struct cname {
+	const char *name;
 	char code;
 } cnames[] = {
 	{"NUL",	'\0'},