Re: Useless use of constants other than 0,1 in void context?

Message-Id: <E14sT8l-0004IE-00@libra.cus.cam.ac.uk>

p4raw-id: //depot/perl@9838

diff --git a/op.c b/op.c
index 207e762..7d28e36 100644 (file)
--- a/op.c
+++ b/op.c
@@ -1137,6 +1137,9 @@ Perl_scalarvoid(pTHX_ OP *o)
        else {
            if (ckWARN(WARN_VOID)) {
                useless = "a constant";
+               /* the constants 0 and 1 are permitted as they are
+                  conventionally used as dummies in constructs like
+                       1 while some_condition_with_side_effects;  */
                if (SvNIOK(sv) && (SvNV(sv) == 0.0 || SvNV(sv) == 1.0))
                    useless = 0;
                else if (SvPOK(sv)) {