Qt is more like gtk rather than glib. Although it does come with a fantastic core library.
But if you can move to C++, the standard library already offers great replacements for most glib features. Glib exists mostly because the C standard library is lacking in many aspects.
That's only partially true. You'd really something like boost to cover a lot of things that glib provides for C. glib covers many, many things that are outside of the scope of both the C++ and C standard libraries.
In the same way that using glib does not mean you are forced to use Gtk, you can use pieces of Qt without pulling in the GUI library. That's why I mentioned "non-GUI" explicitly.
