avoid warning in IO::Select::exists() if socket doesn't exist

p4raw-id: //depot/perl@4628

diff --git a/ext/IO/lib/IO/Select.pm b/ext/IO/lib/IO/Select.pm
index f021a79..7917102 100644 (file)
--- a/ext/IO/lib/IO/Select.pm
+++ b/ext/IO/lib/IO/Select.pm
@@ -46,7 +46,9 @@ sub remove
 sub exists
 {
  my $vec = shift;
- $vec->[$vec->_fileno(shift) + FIRST_FD];
+ my $fno = $vec->_fileno(shift);
+ return undef unless defined $fno;
+ $vec->[$fno + FIRST_FD];
 }