Sphinx\SphinxClient::connect PHP Method

    private function connect()
    {
        if ($this->socket !== false) {
            // we are in persistent connection mode, so we have a socket
            // however, need to check whether it's still alive
            if (!@feof($this->socket)) {
                return $this->socket;
            }
            // force reopen
            $this->socket = false;
        }
        $errno = 0;
        $errstr = '';
        $this->connerror = false;
        if ($this->path) {
            $host = $this->path;
            $port = 0;
        } else {
            $host = $this->host;
            $port = $this->port;
        }
        if ($this->timeout <= 0) {
            $fp = @fsockopen($host, $port, $errno, $errstr);
        } else {
            $fp = @fsockopen($host, $port, $errno, $errstr, $this->timeout);
        }
        if (!$fp) {
            if ($this->path) {
                $location = $this->path;
            } else {
                $location = $this->host . ':' . $this->port;
            }
            $errstr = trim($errstr);
            $this->error = sprintf('connection to %s failed (errno=%d, msg=%s)', $location, $errno, $errstr);
            $this->connerror = true;
            return false;
        }
        // send client version
        // this is a subtle part. we must do it before (!) reading back from searchd.
        // because otherwise under some conditions (reported on FreeBSD for instance)
        // TCP stack could throttle write-write-read pattern because of Nagle.
        if (!$this->send($fp, pack('N', 1), 4)) {
            fclose($fp);
            $this->error = 'failed to send client protocol version';
            return false;
        }
        // check version
        list(, $v) = unpack('N*', fread($fp, 4));
        $v = (int) $v;
        if ($v < 1) {
            fclose($fp);
            $this->error = sprintf('expected searchd protocol version 1+, got version \'%d\'', $v);
            return false;
        }
        return $fp;
    }