DNS

This section details resolving hostnames to addresses, as well as conditions/events that occur while using the DNS system.

• dns-lookup function
• dns-error condition

dns-lookup

(defun dns-lookup (host resolve-cb event-cb &key (family +af-unspec+)))
  => nil

Asynchronously lookup an IP address given a hostname. If the hostname is an IP address already, the mechanics are the same although the callback is called synchronously.

The :family keyword can be one of +af-inet+, +af-inet6+, +af-unspec+.

;; example
(dns-lookup "www.google.com"
            (lambda (host family)
              (format t "Address: ~a~%" host))
            (lambda (err) (format t "err: ~a~%" err)))

resolve-cb definition

(lambda (ip-address-string ip-address-family) ...)

ip-address-family will be either +af-inet+ or +af-inet6+.

Conditions

These are the conditions the DNS system can signal in event callbacks.

dns-error

extends event-error

This explains a DNS error (for instance if a DNS lookup fails).