---
title: dataWritten
framework: corefoundation
role: symbol
role_heading: Type Property
path: corefoundation/cfstreampropertykey/datawritten
---

# dataWritten

Value is a CFData object that contains all the bytes written to a writable memory stream. You cannot modify this value.

## Declaration

```swift
static let dataWritten: CFStreamPropertyKey!
```

## See Also

### Constants

- [appendToFile](corefoundation/cfstreampropertykey/appendtofile.md)
- [fileCurrentOffset](corefoundation/cfstreampropertykey/filecurrentoffset.md)
- [socketNativeHandle](corefoundation/cfstreampropertykey/socketnativehandle.md)
- [socketRemoteHostName](corefoundation/cfstreampropertykey/socketremotehostname.md)
- [socketRemotePortNumber](corefoundation/cfstreampropertykey/socketremoteportnumber.md)
- [kCFStreamPropertyShouldCloseNativeSocket](corefoundation/kcfstreampropertyshouldclosenativesocket.md)
- [kCFStreamPropertySocketSecurityLevel](corefoundation/kcfstreampropertysocketsecuritylevel.md)
- [kCFStreamPropertySSLPeerCertificates](cfnetwork/kcfstreampropertysslpeercertificates.md)
- [kCFStreamPropertySSLPeerTrust](cfnetwork/kcfstreampropertysslpeertrust.md)
- [kCFStreamPropertySSLSettings](cfnetwork/kcfstreampropertysslsettings.md)
- [kCFStreamPropertySSLContext](cfnetwork/kcfstreampropertysslcontext.md)
- [kCFStreamPropertySOCKSProxy](corefoundation/kcfstreampropertysocksproxy.md)
- [kCFStreamPropertyProxyLocalBypass](cfnetwork/kcfstreampropertyproxylocalbypass.md)
- [kCFStreamPropertySocketRemoteHost](cfnetwork/kcfstreampropertysocketremotehost.md)
- [kCFStreamPropertySocketRemoteNetService](cfnetwork/kcfstreampropertysocketremotenetservice.md)