pp_hot.c:pp_subst: add comment

diff --git a/pp_hot.c b/pp_hot.c
index 6d56d66..9c66684 100644 (file)
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -2062,7 +2062,7 @@ PP(pp_subst)
     int force_on_match = 0;
     const I32 oldsave = PL_savestack_ix;
     STRLEN slen;
-    bool doutf8 = FALSE;
+    bool doutf8 = FALSE; /* whether replacement is in utf8 */
 #ifdef PERL_OLD_COPY_ON_WRITE
     bool is_cow;
 #endif