add comment at undef postinc special case

p4raw-id: //depot/perl@19015

diff --git a/pp.c b/pp.c
index ba6bf07..8e496c8 100644 (file)
--- a/pp.c
+++ b/pp.c
@@ -857,6 +857,7 @@ PP(pp_postinc)
     else
        sv_inc(TOPs);
     SvSETMAGIC(TOPs);
+    /* special case for undef: see thread at 2003-03/msg00536.html in archive */
     if (!SvOK(TARG))
        sv_setiv(TARG, 0);
     SETs(TARG);