# Error code of `Sys::h_errno`
extern class HErrno `{ int `}
	# The specified host is unknown
	fun host_not_found: Bool `{ return self == HOST_NOT_FOUND; `}

	# The requested name is valid but does not have an IP address
	#
	# Same as `no_data`.
	fun no_address: Bool `{ return self == NO_ADDRESS; `}

	# The requested name is valid byt does not have an IP address
	#
	# Same as `no_address`.
	fun no_data: Bool `{ return self == NO_DATA; `}

	# A nonrecoverable name server error occurred
	fun no_recovery: Bool `{ return self == NO_RECOVERY; `}

	# A temporary error occurred on an authoritative name server, try again later
	fun try_again: Bool `{ return self == TRY_AGAIN; `}

	redef fun to_s
	do
		if host_not_found then
			return "The specified host is unknown"
		else if no_address then
			return "The requested name is valid but does not have an IP address"
		else if no_recovery then
			return "A nonrecoverable name server error occurred"
		else if try_again then
			return "A temporary error occurred on an authoritative name server, try again later"
		else
			# This may happen if another call was made to `gethostbyname`
			# before we fetch the error code.
			return "Unknown error on `gethostbyname`"
		end
	end
end