[clean-list] Finalizer

[John van Groningen]

Shivkumar Chandrasekaran wrote:
>Is there a way (even ABC code) to call a finalizer for an object that is about to be garbage collected in Clean?

The function make_finalizer defined in the module below creates an object in
the heap containing the address of a c function and an argument for this
function. If the object becomes garbage during a garbage collection,
the c function will be called with this argument at the end of the garbage
collection. This c function cannot call back to Clean.

Kind regards,

John van Groningen




definition module finalizer;

make_finalizer :: !Int /*address of c function*/ !Int /*argument of c function*/ -> Finalizer;

:: Finalizer = {finalizer_implementation::!FinalizerT};

:: FinalizerT;




implementation module finalizer;

:: Finalizer = {finalizer_implementation::!FinalizerT};

:: FinalizerT = DummyFinalizer !Int !Int !Int;

make_finalizer :: !Int !Int -> Finalizer;
make_finalizer f v
	# (finalizer,_) = make_finalizer_c f v;
	= {finalizer_implementation=finalizer};

make_finalizer_c :: !Int !Int -> (!FinalizerT,!Int);
make_finalizer_c f v = code {
	push_finalizers
	push_a_b 0
	pop_a 1
	build_r e__system_kFinalizer 0 3 0 0
	pop_b 3
	set_finalizers
	pushI 0
};