#! perl
use strict;
use warnings;

my $in_file  = 'temp1.txt';   # this must exist
my $outfile  = 'temp2.txt';
my $arrayref = [];

open(my $in,  '<', $in_file) or die "Cannot open file '$in_file' for reading: $!";
open(my $out, '>', $outfile) or die "Cannot open file '$outfile' for writing: $!";

can_write( $in_file,   $in);
can_write( $outfile,   $out);
can_write('$arrayref', $arrayref);

close($in)                   or die "Cannot close file '$in_file': $!";
close($out)                  or die "Cannot close file '$outfile': $!";

sub can_write
{
    my ($name, $fh) = @_;
    my  $result     = eval { no warnings; print $fh '' };

    printf "$name %s write\n", ($result ? 'can' : 'cannot');
}

__END__
temp1.txt cannot write
temp2.txt can write
$arrayref cannot write