sv.h: Add comment about gv_check and SvIsCOW

So that future refactorings don’t make use of 0x00010000 on
hashes without modifying gv_check to account.

diff --git a/sv.h b/sv.h
index c63aeff..cd15924 100644 (file)
--- a/sv.h
+++ b/sv.h
@@ -363,6 +363,7 @@ perform the upgrade if necessary.  See C<svtype>.
 #define SVpad_NAMELIST SVp_SCREAM  /* AV is a padnamelist */
 #define SVf_IsCOW      0x00010000  /* copy on write (shared hash key if
                                       SvLEN == 0) */
+                                   /* Also used on HVs in gv.c:gv_check */
 #define SVs_PADTMP     0x00020000  /* in use as tmp; only if ! SVs_PADMY */
 #define SVs_PADSTALE   0x00020000  /* lexical has gone out of scope;
                                        only valid for SVs_PADMY */