$loop_count = 10;
while( ! $done and $loop_count-- ) {
   $done = is_it_done_yet();
   sleep 1;
}

##</code><code>##

while( ! $done ) {
   eval {
      local $SIG{ALRM} = sub { die "alarm\n" };
      alarm 10;
      $done = is_it_done_yet();
      alarm 0;
   };
   last if @$ and $@ eq "alarm\n"; # hit alarm timeout
   sleep 1;
}