Adds a #GTypeClassCacheFunc to be called before the reference count of a
class goes from one to zero. This can be used to prevent premature class
destruction. All installed #GTypeClassCacheFunc functions will be chained
until one of them returns %TRUE. The functions have to check the class id
passed in to figure whether they actually want to cache the class of this
type, since all classes are routed through the same #GTypeClassCacheFunc
chain.
Adds a #GTypeClassCacheFunc to be called before the reference count of a class goes from one to zero. This can be used to prevent premature class destruction. All installed #GTypeClassCacheFunc functions will be chained until one of them returns %TRUE. The functions have to check the class id passed in to figure whether they actually want to cache the class of this type, since all classes are routed through the same #GTypeClassCacheFunc chain.