Re^3: Race when redirecting output.

[ikegami]

It doesn't need to be an open handle. You can use tie *FH, ... out of the blue. You can use tie local *FH, ... for something localized.

$ perl -e'
   use v5.40;
   use feature qw( bareword_filehandles );

   use Tie::Simple qw( );

   tie *FH, Tie::Simple::, undef,
      PRINT => sub {
         shift;
         my $msg = join( defined( $, ) ? $, : "", @_ );
         $msg .= $\ if defined( $\ );
         say STDOUT "[$msg]";
      };

   say FH "Hello!";
'
[Hello!
]

Without bare word file handles:

$ perl -e'
   use v5.40;

   use Symbol      qw( gensym );
   use Tie::Simple qw( );

   my $fh = gensym;

   tie *$fh, Tie::Simple::, undef,
      PRINT => sub {
         shift;
         my $msg = join( defined( $, ) ? $, : "", @_ );
         $msg .= $\ if defined( $\ );
         say STDOUT "[$msg]";
      };

   say $fh "Hello!";
'
[Hello!
]