Each element has three functions which are used for construction of an
element. These are the _base_init()
function which
is meant to initialize class and child class properties during each new
child class creation; the _class_init()
function,
which is used to initialise the class only once (specifying what signals,
arguments and virtual functions the class has and setting up global
state); and the _init()
function, which is used to
initialise a specific instance of this type.