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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 0x7fb10c063eb0
freeing memory at 0x7fb10c066260
freeing memory at 0x7fb10c0573f0
freeing memory at 0x7fb10c0573d0
freeing memory at 0x7fb10c068720
freeing memory at 0x7fb10c06a0f0
freeing memory at 0x7fb10c066980
freeing memory at 0x7fb10c068740
freeing memory at 0x7fb10c066280
freeing memory at 0x7fb10c006fa0

See also

Ways to use this method: