TypeClass

addPrivate void addPrivate(size_t privateSize): Registers a private structure for an instantiatable type.
getInstancePrivateOffset int getInstancePrivateOffset(): Gets the offset of the private data for instances of g_class.
getPrivate void* getPrivate(GType privateType)
getStruct void* getStruct(): the main Gtk struct as a void*
getTypeClassStruct GTypeClass* getTypeClassStruct(bool transferOwnership): Get the main Gtk struct
peekParent TypeClass peekParent(): This is a convenience function often needed in class initializers. It returns the class structure of the immediate parent type of the class passed in. Since derived classes hold a reference count on their parent classes as long as they are instantiated, the returned class will always exist.
unref void unref(): Decrements the reference count of the class structure being passed in. Once the last reference count of a class has been released, classes may be finalized by the type system, so further dereferencing of a class pointer after TypeClass.unref are invalid.
unrefUncached void unrefUncached(): A variant of TypeClass.unref for use in GTypeClassCacheFunc implementations. It unreferences a class without consulting the chain of GTypeClassCacheFuncs, avoiding the recursion which would occur otherwise.

adjustPrivateOffset void adjustPrivateOffset(void* gClass, int* privateSizeOrOffset)
peek TypeClass peek(GType type): This function is essentially the same as TypeClass.ref, except that the classes reference count isn't incremented. As a consequence, this function may return NULL if the class of the type passed in does not currently exist (hasn't been referenced before).
peekStatic TypeClass peekStatic(GType type): A more efficient version of TypeClass.peek which works only for static types.
ref_ TypeClass ref_(GType type): Increments the reference count of the class structure belonging to type. This function will demand-create the class if it doesn't exist already.