---
title: NSURLSessionTransferSizeUnknown
framework: foundation
role: symbol
role_heading: Global Variable
path: foundation/nsurlsessiontransfersizeunknown
---

# NSURLSessionTransferSizeUnknown

The total size of the transfer cannot be determined.

## Declaration

```swift
let NSURLSessionTransferSizeUnknown: Int64
```

## See Also

### Obtaining task progress

- [progress](foundation/urlsessiontask/progress.md)
- [countOfBytesExpectedToReceive](foundation/urlsessiontask/countofbytesexpectedtoreceive.md)
- [countOfBytesReceived](foundation/urlsessiontask/countofbytesreceived.md)
- [countOfBytesExpectedToSend](foundation/urlsessiontask/countofbytesexpectedtosend.md)
- [countOfBytesSent](foundation/urlsessiontask/countofbytessent.md)