library/Rediska/Key/List.php
public function popBlocking($timeout = 0, $pushToKey = null)
    {
        $result = $this->_getRediskaOn()->popFromListBlocking($this->getName(), $timeout, $pushToKey);

        if (!is_null($this->getExpire()) && $result) {
            $this->expire($this->getExpire(), $this->isExpireTimestamp());
        }

        return $result;
    }
public function popBlocking($timeout = 0, $pushToKey = null)
    {
        $result = $this->_getRediskaOn()->popFromListBlocking($this->getName(), $timeout, $pushToKey);

        if (!is_null($this->getExpire()) && $result) {
            $this->expire($this->getExpire(), $this->isExpireTimestamp());
        }

        return $result;
    }
Return and remove the last element of the List and block if list empty or not exists.

@param integer $timeout[optional]   Blocking timeout. 0 for default - timeout is disabled.
@param string  $pushToKey[optional] If not null - push value to another list.
@return mixed