# init(destination:words:wordsToSend:complete:completionProc:completionRefCon:) Creates a new single universal MIDI packet (UMP) system-exclusive (SysEx) event request. ``` init(destination: MIDIEndpointRef, words: UnsafeMutablePointer, wordsToSend: UInt32, complete: DarwinBoolean, completionProc: MIDICompletionProcUMP, completionRefCon: UnsafeMutableRawPointer?) ``` ## Parameters `destination` The endpoint to send the event to. `words` Initially, a pointer to the UMP SysEx event to send. The system advances this pointer as it sends the data. `wordsToSend` Initially, a counter of the number of words to send. The system decrements this counter as it sends the data. `complete` A Boolean value that indicates whether the transmission is complete. You can set this value to `true` to abort transmission. The system sets it to `true` after it transmits all the bytes. `completionProc` A function that the system calls after it sends all data for the request, or after the client sets `complete` to `true`. `completionRefCon` Data to pass to the `completionProc`. --- Copyright © 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)