SvFLAGS: informally reserve a bit

SvFAKE is currently unused on HVs, so I'm marking it as mine.
Hopefully it will eventually get used for vtables on HVs.

I've also improved the description of SVs_TEMP.

diff --git a/sv.h b/sv.h
index 7479624..8876449 100644 (file)
--- a/sv.h
+++ b/sv.h
@@ -369,7 +369,7 @@ perform the upgrade if necessary.  See C<svtype>.
 #define SVpad_TYPED    0x00020000  /* pad name is a Typed Lexical */
 #define SVs_PADMY      0x00040000  /* in use a "my" variable */
 #define SVpad_OUR      0x00040000  /* pad name is "our" instead of "my" */
-#define SVs_TEMP       0x00080000  /* string is stealable? */
+#define SVs_TEMP       0x00080000  /* mortal (implies string is stealable) */
 #define SVs_OBJECT     0x00100000  /* is "blessed" */
 #define SVs_GMG                0x00200000  /* has magical get method */
 #define SVs_SMG                0x00400000  /* has magical set method */
@@ -382,7 +382,9 @@ perform the upgrade if necessary.  See C<svtype>.
                                          [CvEVAL(cv), CvSPECIAL(cv)]
                                       3: On a pad name SV, that slot in the
                                          frame AV is a REFCNT'ed reference
-                                         to a lexical from "outside". */
+                                         to a lexical from "outside".
+                                       4: HV: informally reserved by DAPM
+                                          for vtables */
 #define SVf_OOK                0x02000000  /* has valid offset value. For a PVHV this
                                       means that a hv_aux struct is present
                                       after the main array */