code: public function write($uid, $mixed) {
          if (!is_int($uid) && !is_numeric($uid)) {
              throw new Exception\RuntimeException('Segment type key must integer or numeric.');
          }
          if (is_object($mixed) && method_exists($mixed, '__toString')) {
              $mixed = $mixed->__toString();
          }
          if (is_int($mixed) || is_float($mixed) || is_bool($mixed)) {
              $mixed = (string) $mixed;
          }
          if (!is_string($mixed)) {
              $mixed = '';
          }
          if ($uid * $this->blocSize >= $this->segmentSize) {
              throw new Exception\RuntimeException('Invalid access bloc. Only ' . floor($this->segmentSize / $this->blocSize) . ' blocs are allowed.');
          }
          $this->alloc();
          $limit = $this->getBlocSize();
          $str = mb_substr($mixed, 0, $limit);
          $str = str_pad($str, $this->blocSize);
          return shmop_write($this->memory, $str, $uid * $this->blocSize);
      }
docs: Write datas on $uid key
  @param mixed $uid
  @param mixed $mixed