---
title: NSURLResponseUnknownLength
framework: foundation
role: symbol
role_heading: Macro
path: foundation/nsurlresponseunknownlength
---

# NSURLResponseUnknownLength

The response length cannot be determined in advance of receiving the data from the server.

## Declaration

```occ
#define NSURLResponseUnknownLength
```

## Discussion

Discussion For example, NSURLResponseUnknownLength is returned when the server HTTP response does not include a Content-Length header.

## See Also

### Getting the response properties

- [expectedContentLength](foundation/urlresponse/expectedcontentlength.md)
- [suggestedFilename](foundation/urlresponse/suggestedfilename.md)
- [mimeType](foundation/urlresponse/mimetype.md)
- [textEncodingName](foundation/urlresponse/textencodingname.md)
- [url](foundation/urlresponse/url.md)