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registerFinalizer(ForeignObject,Function) -- register a finalizer for a foreign object

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 0x7f0d08071480
freeing memory at 0x7f0d08071790
freeing memory at 0x7f0d0806dfa0
freeing memory at 0x7f0d08071030
freeing memory at 0x7f0d0806a7c0
freeing memory at 0x7f0d0806d4c0
freeing memory at 0x7f0d08007030
freeing memory at 0x7f0d0806cd50
freeing memory at 0x7f0d08071050
freeing memory at 0x7f0d080714a0

See also

Ways to use this method:


The source of this document is in ForeignFunctions.m2:1806:0.