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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 0x7fcd3004f1b0
freeing memory at 0x7fcd3004f870
freeing memory at 0x7fcd3004f820
freeing memory at 0x7fcd3004f840
freeing memory at 0x7fcd3004f4d0
freeing memory at 0x7fcd3004e9b0
freeing memory at 0x7fcd30048990
freeing memory at 0x7fcd3004f7b0
freeing memory at 0x7fcd300075a0

Ways to use this method: