How to use dhcpctl_set_callback? (Modified by Mark Dominus)

[Mark Dominus]

I'm trying to make an asynchronous dhcpctl request, as mentioned in
the dhcpctl(3) manual and also in the documents in doc/api+protocol.
I can't get the library (dhcpctl-3.0pl2) to do anything except dump
core.

I can't find any examples of the correct use of dhcpctl_set_callback
online or in any of the source code in the distribution.

I've placed my example source code at
http://www.plover.com/~mjd/misc/dhcp/callback.c if anyone wants to
look at it.  I've also tried many minor variations of this code.  I've
tried putting the dhcpctl_set_callback call at every reasonable place
in the program, but all it does is segfault, always somewhere inside
the omapi library.

If anyone on the list has ever used dhcpctl_set_callback successfully,
I'd apperciate advice or working examples.

Thanks.