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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 0x600000a78230
freeing memory at 0x600000a78220
freeing memory at 0x600000a78150
freeing memory at 0x600000a78250
freeing memory at 0x600000a78240
freeing memory at 0x600000a78120
freeing memory at 0x600000a78170
freeing memory at 0x600000a781b0
freeing memory at 0x600000a78200
freeing memory at 0x600000a78210

Ways to use this method: