Gets the error subdomain associated with errors in the
k domain from the
CFStream returned by a stream operation.
- iOS 2.0+
- macOS 10.2+
- Mac Catalyst 13.0+
- tvOS 9.0+
The error value to decode.
Error codes in the
k domain can come from multiple parts of the protocol stack, many of which define their own error values as part of outside specifications such as the HTTP specification.
To avoid confusion from conflicting error numbers, error codes in the
k domain contain two parts: a subdomain, which tells which part of the protocol stack generated the error, and the error code itself.
CFSocket returns an identifier that tells which layer of the protocol stack produced the error. The possible values are listed in Data Types. With this information, you can interpret the error codes returned by