On Aug 21, 2019, at 7:35 AM, Xinhuan Zheng <xzheng@xxxxxxxxxxxxxxxxx> wrote: > > my $s = IO::Select->new( $fh ); > if ( $io->can_write( 10 ) { That’s not designed to do what you hope. select(2) is a system call intended for use on network socket handles, not file handles. Since socket handles and file handles are compatible on a Unix type system (including CentOS) the call doesn’t fail, but it *cannot* report the information you’re hoping to get. I would first try calling the -w operator: print_to_file() if -w $fh; _______________________________________________ CentOS mailing list CentOS@xxxxxxxxxx https://lists.centos.org/mailman/listinfo/centos