use v5.12;
use warnings;
use Data::Dump qw/pp dd/;




sub tst {
    my $vers = shift;

    open STDOUT, ">-";                  # restore STDOUT
    $|=1;


    say STDERR "********* testing $vers\n";

    my $fh;

    open $fh, ">-" if $vers eq "open2";
    $fh = \*STDOUT if $vers eq "copyref";
    open $fh, '>&', STDOUT if $vers eq "redirect";


    $fh->autoflush;

    say "$vers 1";

    close STDOUT;

    say $fh "$vers 2";

    say "$vers 3";
}


tst("redirect");

tst("open2");

tst("copyref");