At Wed, 5 Mar 2014 12:02:08 +0100, Pasquale Dir wrote: You can always have a look at the C API documentation: http://libvirt.org/html/libvirt-libvirt.html#virConnectOpenAuth and http://libvirt.org/html/libvirt-libvirt.html#virConnectFlags In your case, not passing the READ_ONLY flag means you get a read-write connection. I'm going to push a patch[1] improving this situation shortly. IMO, it is a bad thing (ab-)using an int for a flags parameter, where you don't have a hint from the compiler / IDE what kind of flags are acceptable. I'm going to improve this situation further in the future. Claudio [1]: https://www.redhat.com/archives/libvir-list/2014-February/msg00879.html