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ForeignFunctions :: registerFinalizer(ForeignObject,Function)

registerFinalizer(ForeignObject,Function) -- register a finalizer for a foreign object

Synopsis

Description

If a foreign pointer object corresponds to memory that was not allocated by the GC garbage collector, then a function to properly deallocate this memory when the Pointer object that stores this pointer is garbage collected should be called. The function should take a single argument, a foreign object, typically of type voidstar, which corresponds to the memory to deallocate.

i1 : malloc = foreignFunction("malloc", voidstar, ulong)

o1 = malloc

o1 : ForeignFunction
i2 : free = foreignFunction("free", void, voidstar)

o2 = free

o2 : ForeignFunction
i3 : finalizer = x -> (print("freeing memory at " | net x); free x)

o3 = finalizer

o3 : FunctionClosure
i4 : for i to 9 do (x := malloc 8; registerFinalizer(x, finalizer))
i5 : collectGarbage()
freeing memory at 0xffff8c04f5f0
freeing memory at 0xffff8c04f630
freeing memory at 0xffff8c04f5d0
freeing memory at 0xffff8c04fe60
freeing memory at 0xffff8c04ff20
freeing memory at 0xffff8c04f880
freeing memory at 0xffff8c04f860
freeing memory at 0xffff8c048a10
freeing memory at 0xffff8c048a30

Ways to use this method: