Callbacks help please

I need some help getting my head around the callback system peoples. The situation: with IPv6 I have it looking up records and failover to lookup the A records at the DNS level. However IFF the DNS server responds to the indicating a CNAME. THe case is quite common that the CNAME

/dev/poll support is in squid-2.6

I've just merged in the Solaris/irix support into squid-2.6. I'm running a quick polygraph test on an old sun (E250) running Solaris 10 to see if there are any issues. Adrian