---
title: "AEStreamWriteKey(_:_:)"
framework: coreservices
role: symbol
role_heading: Function
path: coreservices/1448750-aestreamwritekey
---

# AEStreamWriteKey(_:_:)

Marks the beginning of a keyword/descriptor pair for a descriptor in an AEStreamRef.

## Declaration

```swift
func AEStreamWriteKey(_ ref: AEStreamRef!, _ key: AEKeyword) -> OSStatus
```

## Parameters

- `ref`: An doc://com.apple.documentation/documentation/coreservices/aestreamref containing the stream data.
- `key`: The AEKeyword associated with the new descriptor being added to the stream. See doc://com.apple.documentation/documentation/coreservices/aekeyword.

## Return Value

Return Value A result code. See Result Codes.

## Discussion

Discussion You must follow this call with a sequence of “AEStream” calls to specify exactly one descriptor that goes with the keyword. The descriptor you create can be of type AEDesc, AEDescList, or AERecord. If you are creating nested descriptors, this routine begins a new keyword/descriptor pair for the descriptor most recently opened by a call to AEStreamWriteKey(_:_:) or AEStreamOpenEvent(_:). You cannot use this routine to write parameters to any other types of descriptors, even if they are nested inside of an AERecord.

## See Also

### Creating Apple Event Structures Using Streams

- [AEStreamClose(_:_:)](coreservices/1449821-aestreamclose.md)
- [AEStreamCloseDesc(_:)](coreservices/1449272-aestreamclosedesc.md)
- [AEStreamCloseList(_:)](coreservices/1448185-aestreamcloselist.md)
- [AEStreamCloseRecord(_:)](coreservices/1449522-aestreamcloserecord.md)
- [AEStreamCreateEvent(_:_:_:_:_:_:_:)](coreservices/1446562-aestreamcreateevent.md)
- [AEStreamOpen()](coreservices/1447732-aestreamopen.md)
- [AEStreamOpenDesc(_:_:)](coreservices/1446544-aestreamopendesc.md)
- [AEStreamOpenEvent(_:)](coreservices/1445366-aestreamopenevent.md)
- [AEStreamOpenKeyDesc(_:_:_:)](coreservices/1442897-aestreamopenkeydesc.md)
- [AEStreamOpenList(_:)](coreservices/1448594-aestreamopenlist.md)
- [AEStreamOpenRecord(_:_:)](coreservices/1447141-aestreamopenrecord.md)
- [AEStreamOptionalParam(_:_:)](coreservices/1444481-aestreamoptionalparam.md)
- [AEStreamSetRecordType(_:_:)](coreservices/1447704-aestreamsetrecordtype.md)
- [AEStreamWriteAEDesc(_:_:)](coreservices/1448487-aestreamwriteaedesc.md)
- [AEStreamWriteData(_:_:_:)](coreservices/1442610-aestreamwritedata.md)
- [AEStreamWriteDesc(_:_:_:_:)](coreservices/1450387-aestreamwritedesc.md)
- [AEStreamWriteKeyDesc(_:_:_:_:_:)](coreservices/1442568-aestreamwritekeydesc.md)