Re: Avahi Support on Linux

Hello Caolan, Tor,

I've done some research and I've more or less understood how it works now.

Now, with Avahi, I am supposed to use dlsym to import several functions
from libavahi-client.so.3 and libavahi-common.so.3 during the runtime.
However, the dlsym should return a pointer to the function which, in order
to be used, need to be casted with correct return type/argument types. The
problem is, these types are declared in the shared object and I still don't
have access to them.

For example, I can dlsym this function and get the void * to it, but how
can I use it if I don't have access to the struct AvahiClient (declaired in
the shared object)?
AvahiClient<http://avahi.org/download/doxygen/client_8h.html#a3d65e9ea7182c44fa8df04a72f1a56bb>
* 
avahi_client_new<http://avahi.org/download/doxygen/client_8h.html#a07b2a33a3e7cbb18a0eb9d00eade6ae6>
(const AvahiPoll <http://avahi.org/download/doxygen/struct_avahi_poll.html>
 * poll_api, 
AvahiClientFlags<http://avahi.org/download/doxygen/client_8h.html#a46a797e5d352f6f98261834ae3b1a3ed>
  
flags,AvahiClientCallback<http://avahi.org/download/doxygen/client_8h.html#a24ece0cd8c27c269a1ddd3cf3acf6444>
  callback,void * userdata, int * error  )

Am I on the right track ? Any help or link to some tutorials would be
appreciated!

Thanks!
Siqi


On Thu, Jan 9, 2014 at 4:57 PM, Caolán McNamara <caolanm@redhat.com> wrote:

> On Tue, 2014-01-07 at 15:31 +0100, Siqi Liu wrote:
> > Tor pushed a quick fix for that and disabled avahi temporarily so that
> > it doesn't get compiled unless specified. I'm thinking of fixing that
> > but not sure how to load Avahi dynamically depending on the presence
> > of Avahi library on the distribution.
> >
> > Any pointers on how to achieve that?
>
> We've done stuff like this plenty of times in the past. One current one
> is sc/source/core/opencl/clcc.cxx see the dlopen, dlsym hackery.
>
> C.


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Cordialement,
Siqi LIU

Étudiant Ingénieur, 1ère année
École Supérieur d'Électricité (Supélec)