Initializes the DNS resolver to be used by the library. This in turn calls
either the compiled-in default or the replacement provided by a call to
This is automatically called if the resolver has not yet been initialized and
the library needs to perform a DNS lookup.
||dkim_dns_init() can be called at any time. It always returns
DKIM_DNS_SUCCESS if the resolver was already initialized.
||The library instantiation handle, returned by
- DKIM_DNS_SUCCESS -- successful operation
- DKIM_DNS_INVALID -- already initialized
- DKIM_DNS_ERROR -- an error occurred