The connection
An array of n_contacts
TpContact objects (this callback is not given an extra reference to any of these objects, and must call g_object_ref() on any that it will keep)
An unrecoverable error, or %NULL if the connection remains valid
the weak_object
that was passed to tp_connection_upgrade_contacts()
Signature of a callback used to receive the result of tp_connection_upgrade_contacts().
If an unrecoverable error occurs (for instance, if
connection
becomes disconnected) it is indicated byerror,
but the contacts incontacts
are still provided.