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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 0x7f79b80573f0
freeing memory at 0x7f79b80573d0
freeing memory at 0x7f79b8066260
freeing memory at 0x7f79b8063eb0
freeing memory at 0x7f79b8066980
freeing memory at 0x7f79b8068740
freeing memory at 0x7f79b8068720
freeing memory at 0x7f79b806a0f0
freeing memory at 0x7f79b8006fa0
freeing memory at 0x7f79b8066280

See also

Ways to use this method: