#define CVf_CLONED 0x0002 /* a clone of one of those */
#define CVf_ANON 0x0004 /* CvGV() can't be trusted */
#define CVf_OLDSTYLE 0x0008
-#define CVf_UNIQUE 0x0010 /* can't be cloned */
+#define CVf_UNIQUE 0x0010 /* sub is only called once (eg PL_main_cv,
+ * require, eval). Not to be confused
+ * with the GVf_UNIQUE flag associated
+ * with the :unique attribute */
#define CVf_NODEBUG 0x0020 /* no DB::sub indirection for this CV
(esp. useful for special XSUBs) */
#define CVf_METHOD 0x0040 /* CV is explicitly marked as a method */