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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 0x7ffb6c04f1c0
freeing memory at 0x7ffb6c04f880
freeing memory at 0x7ffb6c04f830
freeing memory at 0x7ffb6c04f850
freeing memory at 0x7ffb6c04f4e0
freeing memory at 0x7ffb6c0075b0
freeing memory at 0x7ffb6c04e9c0
freeing memory at 0x7ffb6c0489a0
freeing memory at 0x7ffb6c04f7c0

Ways to use this method: