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# DNSServiceUpdateRecord(_:_:_:_:_:_:)

Updates a registered resource record.

```
func DNSServiceUpdateRecord(_ sdRef: DNSServiceRef!, _ recordRef: DNSRecordRef!, _ flags: DNSServiceFlags, _ rdlen: UInt16, _ rdata: UnsafeRawPointer!, _ ttl: UInt32) -> DNSServiceErrorType
```

## Parameters

`sdRef`

A DNSServiceRef that was initialized by [`DNSServiceRegister(_:_:_:_:_:_:_:_:_:_:_:_:)`](/documentation/dnssd/DNSServiceRegister(_:_:_:_:_:_:_:_:_:_:_:_:)) or [`DNSServiceCreateConnection(_:)`](/documentation/dnssd/DNSServiceCreateConnection(_:)).

`recordRef`

A DNSRecordRef initialized by [`DNSServiceAddRecord(_:_:_:_:_:_:_:)`](/documentation/dnssd/DNSServiceAddRecord(_:_:_:_:_:_:_:)), or NULL to update the service’s primary txt record.

`flags`

Currently ignored, reserved for future use.

`rdlen`

The length, in bytes, of the new rdata.

`rdata`

The new rdata to be contained in the updated resource record.

`ttl`

The time to live of the updated resource record, in seconds. Most clients should pass 0 to indicate that the system should select a sensible default value.

## Return Value

Returns [`kDNSServiceErr_NoError`](/documentation/dnssd/kDNSServiceErr_NoError) on success, otherwise returns an error code indicating the error that occurred.

## Discussion

The record must either be:

- The primary txt record of a service registered via [`DNSServiceRegister(_:_:_:_:_:_:_:_:_:_:_:_:)`](/documentation/dnssd/DNSServiceRegister(_:_:_:_:_:_:_:_:_:_:_:_:))
- A record added to a registered service via [`DNSServiceAddRecord(_:_:_:_:_:_:_:)`](/documentation/dnssd/DNSServiceAddRecord(_:_:_:_:_:_:_:))
- An individual record registered by [`DNSServiceRegisterRecord(_:_:_:_:_:_:_:_:_:_:_:_:)`](/documentation/dnssd/DNSServiceRegisterRecord(_:_:_:_:_:_:_:_:_:_:_:_:))

---

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