//
//------------------ DOK FILE --------------------------------------------------
+Header	oblivion
=pkg	bios
=title	Oblivion
=short	A mecanism to prevent unwanted desallocation.
=desc	The Oblivion element does not much: it calls a function when it should normally be erased by the Garbage collector.
This is a useful mecanism in various occasions. For example when using [[Join]] it may happen that a thread is freezed in [[joinWait]] while the join is forgotten by other threads.
When this happens, the thread is locked forever. Using an Oblivion element makes possible to attach a function to such a Join, and this function will be called by a new thread when the GC was supposed to delete the join.
This function may call [[joinSend]] to free the awaiting thread.

Remaining oblivion element functions are also called before the virtual machine exits.
//
//
//------------------ PROTO ----------------------------------------------------- Oblivion
+Proto	Oblivion
=type	Oblivion
=mode	type
=pkg	bios
=impl	native
=link	
=desc	The Oblivion type
//
//
//------------------ PROTO ----------------------------------------------------- oblivionCreate
+Proto	oblivionCreate
=type	fun (fun -> a1) -> Oblivion
=mode	Function
=pkg	bios
=impl	mcy
=link	
=desc	
This function creates an Oblivion element attached to a function.
This function will be called only once when the element is about to be deallocated by the Garbage collector. It is called in a dedicated thread.
In particular, the function is called before the virtual machine terminates, when it deallocates everything.
//
+arg	f
=type	fun -> a1
=desc	A function with no argument
//
+arg	result
=type	Oblivion
=desc	The oblivion element