Need explanation about this code.

[Raheel Hassan]

Hello,

I have problems in understanding $...@$ use ?????

1- my $ref = $$temp_sth -> fetchall_arrayref({});
    for(my $i=0; $i <= $...@$ref}; $i++) {
    push(@$temp_table,$ref->[$i]);}

Can some one explain the under given function.
2- sub buildSensorsHashtable
    {

   my ($dbh) = @_;
   my $error = 0;

         my $query = "SELECT * FROM Sensors";
         my $sth = $dbh->prepare($query);
         if(!$sth || !($sth->execute())) { $error = 1 ;
 }

         my $ref = $sth->fetchall_arrayref({});
         my %s;
         my @s = @$ref;
    foreach (@s)
    {
        if($_->{"StatusID"} eq "1") { $s{$_->{"IP"}} = $_->{"SensorID"}; }
    }

    return (\%s,$error);

3- Which is the best tool for debuging perl programs having CGI support. I
used DDD but that does not support CGI.

Regards,
Raheel