Libvirt has adopted use of the GLib library. Due to libvirt's long history of development, there are many APIs in libvirt, for which GLib provides an alternative solution. The general rule to follow is that the standard GLib solution will be preferred over historical libvirt APIs. Existing code will be ported over to use GLib APIs over time, but new code should use the GLib APIs straight away where possible.
The following is a list of libvirt APIs that should no longer be used in new code, and their suggested GLib replacements:
VIR_APPEND_ELEMENT, VIR_INSERT_ELEMENT, VIR_DELETE_ELEMENT
https://developer.gnome.org/glib/stable/glib-Arrays.html
Instead of using plain C arrays, it is preferable to use one of the GLib types, GArray, GPtrArray or GByteArray. These all use a struct to track the array memory and size together and efficiently resize.
virObject
https://developer.gnome.org/gobject/stable/gobject-The-Base-Object-Type.html
Prefer GObject instead.