---
title: "CFWriteStreamCopyProperty(_:_:)"
framework: corefoundation
role: symbol
role_heading: Function
path: "corefoundation/cfwritestreamcopyproperty(_:_:)"
---

# CFWriteStreamCopyProperty(_:_:)

Returns the value of a property for a stream.

## Declaration

```swift
func CFWriteStreamCopyProperty(_ stream: CFWriteStream!, _ propertyName: CFStreamPropertyKey!) -> CFTypeRef!
```

## Parameters

- `stream`: The stream to examine.
- `propertyName`: The name of the stream property to obtain. The available properties for standard Core Foundation streams are listed in Stream Properties.

## Return Value

Return Value The value of the property propertyName. Ownership follows the The Create Rule.

## Discussion

Discussion Each type of stream can define a set of properties that either describe or configure individual streams. A property can be any interesting information about a stream. Examples include the headers from an HTTP transmission, the expected number of bytes, file permission information, and so on. Use CFWriteStreamSetProperty(_:_:_:) to modify the value of a property, although some properties are read-only.

## See Also

### Examining Stream Properties

- [CFWriteStreamCanAcceptBytes(_:)](corefoundation/cfwritestreamcanacceptbytes(_:).md)
- [CFWriteStreamCopyError(_:)](corefoundation/cfwritestreamcopyerror(_:).md)
- [CFWriteStreamGetError(_:)](corefoundation/cfwritestreamgeterror(_:).md)
- [CFWriteStreamGetStatus(_:)](corefoundation/cfwritestreamgetstatus(_:).md)