framework/caching/ApcCache.php
protected function setValues($data, $duration)
    {
        $result = $this->useApcu ? apcu_store($data, null, $duration) : apc_store($data, null, $duration);
        return is_array($result) ? array_keys($result) : [];
    }
protected function setValues($data, $duration)
    {
        $result = $this->useApcu ? apcu_store($data, null, $duration) : apc_store($data, null, $duration);
        return is_array($result) ? array_keys($result) : [];
    }
Stores multiple key-value pairs in cache.
@param array $data array where key corresponds to cache key while value
@param int $duration the number of seconds in which the cached values will expire. 0 means never expire.
@return array array of failed keys