Re: [libvirt-users] Where does "cmd" initailize in qemu_command.c?

XML or fall back to the default stored in the virCapsPtr caps structure).

Your questions seem to be more of a development nature about the libvirt source code, and less of a user nature about how to use the API in using the libvirt as a library in your own code. As such, you should probably take future questions of this nature to libvir-lists(a)redhat.com.