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Re: DNSServiceQueryRecord callback won't do

I'd like to extend my question with a little code. Maybe that helps to make my issue to become clear and hopefully gives some suggestions how to deal with it.

The next code works fine to get a single service:

DNSServiceRef client = NULL;
const char *name = "machost";
const char *type = "_afpovertcp._tcp";
const char *domain = "local";
const char fullname[1005];
DNSServiceConstructFullName((char*) &fullname, name,type,domain);
DNSServiceErrorType err;


err = DNSServiceResolve(&client, 0, 0, name, type, domain, resolve_reply, NULL);
if (err != kDNSServiceErr_NoError) {
printf("register returned failure:%d\n", err);
}
DNSServiceProcessResult(client);
DNSServiceRefDeallocate(client);

It will return the hostname and port the service is running on. (only one, I believe)

So I feel that the next code should do the same:

const char* fullname = "machost._afpovertcp._tcp.local.";
//const char* fullname = "_afpovertcp._tcp.local";
printf("looking for %s\n", fullname);
DNSServiceErrorType err;
DNSServiceRef client = NULL;


err = DNSServiceQueryRecord(&client,0,0,fullname,ns_t_ptr,ns_c_in,query_reply,NULL);
if (err != kDNSServiceErr_NoError) {
printf("register returned failure:%d\n", err);
}

DNSServiceProcessResult(client);
DNSServiceRefDeallocate(client);

The DNSServiceQueryRecord gives a result for a query :_afpovertcp._tcp.local. (as found in the comment)
(it actually returns an rrtype = 12 not a rrtype = 1)

But it doesn't work for a single service name. (e.g: machost.....) it seems.

The documentation states to use QueryRecord if you have shared services. I am working on a service that could be available multiple times and the rendezvous based client can select on of them (you can make some algorithms which to pick)

Is it possible to have shared services like that ? and how to use QueryRecord to get these ?
Does the DDNS close the connection after the answer or can more answers be expected based on the query at a later time ?

Kind Regards,

Olger


On Nov 1, 2004, at 8:56 PM, Olger Warnier wrote:

Hi List,

I found quite an extensive discussion on the use of DNSServiceQueryRecord
and the callback found in:

Subject: DNSServiceQueryRecord (was Re: FreeBSD and Solaris)
From: Eric Wing <email@hidden>
Date: Thu, 15 Jul 2004 20:50:15 -0700 (PDT)
it is: http://lists.apple.com/archives/rendezvous-dev/2004/Jul/msg00095.html
But it ends with the remark that the callback doesn't seem to work.
On a linux system, I have a situation like that:

When I use DNSServiceResolve(...) and call the DNSServiceProcessResult
(direct or with a select() loop), the service gets resolved and a hostname
+ port number is available.

But I'd like to use the DNSServiceQueryRecord instead with a seperate
select() loop to make it possible keep shared services.
Using DNSServiceQueryRecord with and call the DNSServiceProcessResult
(again direct of with a select() loop), nothing happens.

I use exact the same servicename,type and domain for both and for the
rrtype and rrclass = 1;

In order to use the DNSServiceQueryRecord, do I need to do some
initialization or something ? Or to make my question a bit more generic.
Someone has any suggestions what could solve this ?

Kind Regards,

Olger


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 >DNSServiceQueryRecord callback won't do (From: "Olger Warnier" <email@hidden>)



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