X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/cad2e5aadfceb1a406f657488ea1c699f44a1487..8f78c13df060827662cfa965c08d7e579573d479:/av.h

diff --git a/av.h b/av.h
index bacf614..def66b9 100644
--- a/av.h
+++ b/av.h
@@ -1,6 +1,6 @@
 /*    av.h
  *
- *    Copyright (c) 1991-1999, Larry Wall
+ *    Copyright (c) 1991-2001, Larry Wall
  *
  *    You may distribute under the terms of either the GNU General Public
  *    License or the Artistic License, as specified in the README file.
@@ -10,21 +10,51 @@
 struct xpvav {
     char*	xav_array;      /* pointer to first array element */
     SSize_t	xav_fill;       /* Index of last element present */
-    SSize_t	xav_max;        /* Number of elements for which array has space */
+    SSize_t	xav_max;        /* max index for which array has space */
     IV		xof_off;	/* ptr is incremented by offset */
     NV		xnv_nv;		/* numeric value, if any */
     MAGIC*	xmg_magic;	/* magic for scalar array */
     HV*		xmg_stash;	/* class package */
 
-    SV**	xav_alloc;	/* pointer to malloced string */
+    SV**	xav_alloc;	/* pointer to beginning of C array of SVs */
     SV*		xav_arylen;
     U8		xav_flags;
 };
 
+
+/* AVf_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.
+ * 
+ * AVf_REIFY is only meaningful on such "fake" AVs (i.e. where AVf_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 and @DB::args have 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
+ */
 #define AVf_REAL 1	/* free old entries */
 #define AVf_REIFY 2	/* can become real */
+
+/* XXX this is not used anywhere */
 #define AVf_REUSED 4	/* got undeffed--don't turn old memory into SVs now */
 
+/*
+=for apidoc AmU||Nullav
+Null AV pointer.
+
+=for apidoc Am|int|AvFILL|AV* av
+Same as C<av_len()>.  Deprecated, use C<av_len()> instead.
+
+=cut
+*/
+
 #define Nullav Null(AV*)
 
 #define AvARRAY(av)	((SV**)((XPVAV*)  SvANY(av))->xav_array)