---
title: protocolError
framework: system
role: symbol
role_heading: Type Property
path: system/errno/protocolerror
---

# protocolError

Protocol error.

## Declaration

```swift
static var protocolError: Errno { get }
```

## Mentioned in

Adopting Swift Error Constants

## Discussion

Discussion Some protocol error occurred. This error is device-specific, but generally isn’t related to a hardware failure. The corresponding C error is EPROTO.

## See Also

### Network Protocol Errors

- [protocolFamilyNotSupported](system/errno/protocolfamilynotsupported.md)
- [protocolNotAvailable](system/errno/protocolnotavailable.md)
- [protocolNotSupported](system/errno/protocolnotsupported.md)
- [protocolWrongTypeForSocket](system/errno/protocolwrongtypeforsocket.md)