<!--
{
  "documentType" : "article",
  "framework" : "MIDIDriverKit",
  "identifier" : "/documentation/MIDIDriverKit/mididriverkit-data-types",
  "metadataVersion" : "0.1.0",
  "role" : "collectionGroup",
  "title" : "MIDIDriverKit Data Types"
}
-->

# MIDIDriverKit Data Types

## Topics

### Data Types

[`enum IOUserMIDIClassID : uint32_t;`](/documentation/MIDIDriverKit/MIDIDriverKit/IOUserMIDIClassID)

[`typedef uint32_t IOUserMIDIObjectID;`](/documentation/MIDIDriverKit/MIDIDriverKit/IOUserMIDIObjectID)

[`enum IOUserMIDIProperty : uint32_t;`](/documentation/MIDIDriverKit/MIDIDriverKit/IOUserMIDIProperty)

[`typedef uint32_t IOUserMIDIPropertySelector;`](/documentation/MIDIDriverKit/MIDIDriverKit/IOUserMIDIPropertySelector)

[`enum IOUserMIDIPropertyType : uint32_t;`](/documentation/MIDIDriverKit/MIDIDriverKit/IOUserMIDIPropertyType)

[`enum IOUserMIDIProtocolID : uint32_t;`](/documentation/MIDIDriverKit/MIDIDriverKit/IOUserMIDIProtocolID)

[`typedef uint32_t IOUserMIDIUMPWord;`](/documentation/MIDIDriverKit/MIDIDriverKit/IOUserMIDIUMPWord)

[`typedef int (^)(const unsigned int *, unsigned long) MIDIIOBlock;`](/documentation/MIDIDriverKit/MIDIDriverKit/MIDIIOBlock)


---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)