---
title: kMIDIPropertyConnectionUniqueID
framework: coremidi
role: symbol
role_heading: Global Variable
path: coremidi/kmidipropertyconnectionuniqueid
---

# kMIDIPropertyConnectionUniqueID

The unique identifier of an external device attached to this connection.

## Declaration

```swift
let kMIDIPropertyConnectionUniqueID: CFString
```

## Discussion

Discussion The value provided may be an integer. To indicate that a driver connects to multiple external objects, pass the array of big-endian SInt32 values as a CFData object. The property is nonexistent or 0 if there’s no connection.

## See Also

### Connections

- [kMIDIPropertyCanRoute](coremidi/kmidipropertycanroute.md)
- [kMIDIPropertyIsBroadcast](coremidi/kmidipropertyisbroadcast.md)
- [kMIDIPropertyIsEmbeddedEntity](coremidi/kmidipropertyisembeddedentity.md)
- [kMIDIPropertySingleRealtimeEntity](coremidi/kmidipropertysinglerealtimeentity.md)