[resolved] Can't use string ("0") as a symbol ref while "strict refs" in use

[bryan.p.spears]

I've written very little code, and this is my first attempt at something in perl, so please forgive the ignorance. I am trying to pass output from an external program called checkuser, into an array. Here is the error:

$ ./testpl.pl [e-mail]
Can't use string ("0") as a symbol ref while "strict refs" in use at .
+/testpl.pl line 29.
$ cat -n testpl.pl | grep 29
    29  open (@checkuser_output, "checkuser $user{'name'}\@$user{'doma
+in'} $domain_action{$user{'domain'}}") || die "Failed: $!\n";

And, for context, here is the script

#!/usr/local/bin/perl -Tw
use strict;
use Data::Dumper;
chomp $ARGV[0];
my %user;
my @input;
my @checkuser_output;         <==== took this out
my $default_domain = 'default.net';
my $maintainer     = '[e-mail]';
my %domain_action  = (
     'default1.net' => 'first',
     'default2.net' => 'second',
     'default3.net' => 'third',
   );
@input = split(/@(.*)/,lc($ARGV[0]));
$user{'name'}   = $input[0] ? $input[0] : '?';
$user{'domain'} = $input[1] ? $input[1] : $default_domain;
my $explanation = <<END;

explanation goes here

END
if ((@ARGV > 1) || ($user{'name'} eq '?'))
{
   printf $explanation;
   exit(1);
};
# placeholder: going to validate domain, here
# Instead of this ====> open (@checkuser_output, "checkuser $user{'nam
+e'}\@$user{'domain'} $domain_action{$user{'domain'}}") || die "Failed
+: $!\n";
open (my $checkuser_output, "checkuser $user{'name'}\@$user{'domain'} 
+$domain_action{$user{'domain'}}") || die "Failed: $!\n";

print Dumper @checkuser_output

Per suggestions by choroba and anonymous (thank you both, very much), I removed the checkuser_output array declaration at top, and referenced it in the open statement as a scalar. One hurdle cleared..

[choroba]

The first argument to open should be a filehandle, not an (empty) array.

[Anonymous Monk]

filehandles are SCALARs, first argument to open is a filehandle, it forces scalar context, @array in scalar context is number of elements (zero), open will try to treat 0 as a filehandle, strict refs forbids it (good)

Use a scalar ( my($fh) )

read perlintro, Tutorials: Context tutorial