X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=av.h;h=f537d9eadbdc5313a50ecddb07ed4b7d7624d3be;hb=52b0428e3435010996923055059a0bfd91b64619;hp=bef763d3b17466dd081572c38b795b9e5cf9776b;hpb=4eb8286e4c6ac94fdae21a64c54a936bc836983e;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/av.h b/av.h
index bef763d..f537d9e 100644
--- a/av.h
+++ b/av.h
@@ -12,7 +12,7 @@ struct xpvav {
     SSize_t	xav_fill;       /* Index of last element present */
     SSize_t	xav_max;        /* Number of elements for which array has space */
     IV		xof_off;	/* ptr is incremented by offset */
-    double	xnv_nv;		/* numeric value, if any */
+    NV		xnv_nv;		/* numeric value, if any */
     MAGIC*	xmg_magic;	/* magic for scalar array */
     HV*		xmg_stash;	/* class package */
 
@@ -21,8 +21,28 @@ struct xpvav {
     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 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
+ */
 #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 */
 
 #define Nullav Null(AV*)