use strict;
use warnings;
use Data::Dumper;

my @fields;
GetTables('ABC', \@fields);

print Dumper(\@fields);

sub GetTables {
   my ($table_name, $aref) = @_;
   my %tables = (
         'ABC' => [ qw( f1 f2 f3)
            ],
         'DEF' => [  'f1', 'f2'
            ],
   );
   
   @$aref = $tables{$table_name}; 
   ## originally I had the following, but it didn't work
   ## $aref = $tables{$table_name};

   print Dumper(\%tables, $aref);
}