[libvirt] [PATCH alternative 2/2] Change contract of virDomainGetID to make it safer

This changes the contract of the existing virDomainGetID call so that it is guaranteed to return the ID provided that the @domain parameter is not NULL or corrupted. This should be compatible with all preceeding versions of libvirt, since all they have ever done is to check the @domain parameter and return the dom->id field. However it might not be forwards compatible with future versions: At the moment there is an odd distinction between the local and remote case. In the local case, the dom->id field is set to -1 when the domain goes (mostly anyhow, not always). In the remote case it is not set, because this is not known. In practice, this never really matters. All significant libvirt callers grab a new virDomain object from the remote end each time, thus getting an updated ID. virDomain objects seem to be individually very short-lived. Rich. -- Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones Read my OCaml programming blog: http://camltastic.blogspot.com/ Fedora now supports 64 OCaml packages (the OPEN alternative to F#) http://cocan.org/getting_started_with_ocaml_on_red_hat_and_fedora