const fix
diff --git a/libasn1parser/asn1p_expr.h b/libasn1parser/asn1p_expr.h
index 9e4ce45..2d72586 100644
--- a/libasn1parser/asn1p_expr.h
+++ b/libasn1parser/asn1p_expr.h
@@ -286,7 +286,7 @@
asn1p_paramlist_t *asn1p_get_namespace(asn1p_expr_t *);
#define TAG2STRING_BUFFER_SIZE 64 /* buf should be at least this big */
-char *asn1p_tag2string(struct asn1p_type_tag_s *tag, char *opt_buf);
+const char *asn1p_tag2string(const struct asn1p_type_tag_s *tag, char *opt_buf);
#define MODULE_NAME_OF(expr) \
((!expr) ? "" : \