sub run_with_timeout {
    my ($cmd, $timeout) = @_;

    local $SIG{ALRM} = sub { die "Timeout\n"; };
    my $out;

    if (my $pid = open my $pipe, "-|") {
        eval {
            alarm $timeout;
            @$out = <$pipe>;
        };
        my $ok = $@ ne "Timeout\n";
        alarm 0;
        if ($ok) {
            close $pipe;
        } else {
            kill 9, $pid;
            waitpid $pid, 0;
        }
        return $out;
        
    } else {
        exec $cmd;
        exit;
   }
}

my $out = run_with_timeout("$solver $file", $timeout);
print defined($out) ? "output of solver:\n@$out" : "timed out";

##</code><code>##

        exec "exec $cmd";