+/* SV* xav_arylen; */
+
+/* SVpav_REAL is set for all AVs whose xav_array contents are refcounted.
+ * Some things like "@_" and the scratchpad list do not set this, to
+ * indicate that they are cheating (for efficiency) by not refcounting
+ * the AV's contents.
+ *
+ * SVpav_REIFY is only meaningful on such "fake" AVs (i.e. where SVpav_REAL
+ * is not set). It indicates that the fake AV is capable of becoming
+ * real if the array needs to be modified in some way. Functions that
+ * modify fake AVs check both flags to call av_reify() as appropriate.
+ *
+ * Note that the Perl stack has neither flag set. (Thus,
+ * items that go on the stack are never refcounted.)
+ *
+ * These internal details are subject to change any time. AV
+ * manipulations external to perl should not care about any of this.
+ * GSAR 1999-09-10
+ */
+
+/*
+=for apidoc ADmnU||Nullav
+Null AV pointer.
+
+(deprecated - use C<(AV *)NULL> instead)
+
+=for apidoc Am|SSize_t|AvFILL|AV* av
+Same as C<L</av_top_index>> or C<L</av_tindex>>.
+
+=for apidoc Cm|SSize_t|AvFILLp|AV* av
+
+If the array C<av> is empty, this returns -1; otherwise it returns the maximum
+value of the indices of all the array elements which are currently defined in
+C<av>. It does not handle magic, hence the C<p> private indication in its name.
+
+=for apidoc Am|SV**|AvARRAY|AV* av
+Returns a pointer to the AV's internal SV* array.
+
+This is useful for doing pointer arithmetic on the array.
+If all you need is to look up an array element, then prefer C<av_fetch>.