foreach my $ss (@str_set) {
    local our @matches;
    $ss =~ m/
          (XXX.*YYY)                 # Search and capture
          (?{ push @matches, $1 })   # Save result
          (?!)                       # Try again
         /x;
    print Dumper \@matches ;
}


##</code><code>##


$VAR = [ # with something ]

# and then empty....

$VAR = [];
$VAR = []; 

etc...