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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 0x7ff4dc04f180
freeing memory at 0x7ff4dc04f7f0
freeing memory at 0x7ff4dc04f810
freeing memory at 0x7ff4dc04f4a0
freeing memory at 0x7ff4dc0075b0
freeing memory at 0x7ff4dc04e980
freeing memory at 0x7ff4dc048960
freeing memory at 0x7ff4dc04f780
freeing memory at 0x7ff4dc04f840

Ways to use this method: