Client/MemcacheClient.php
public function delete($key)
    {
        if ($this->isSafe()) {
            $key = $this->prefix . $key;
            return $this->mem->delete($key, 0);
        }

        return false;
    }
public function delete($key)
    {
        if ($this->isSafe()) {
            $key = $this->prefix . $key;
            return $this->mem->delete($key, 0);
        }

        return false;
    }
Delete a value from the memcache

@param string $key Unique key
@access public
@return void