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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 0x7fe1680714a0
freeing memory at 0x7fe168071790
freeing memory at 0x7fe16806cd50
freeing memory at 0x7fe16806dfa0
freeing memory at 0x7fe16806d4c0
freeing memory at 0x7fe16806a7c0
freeing memory at 0x7fe168071480
freeing memory at 0x7fe168007030
freeing memory at 0x7fe168071050
freeing memory at 0x7fe168071030

See also

Ways to use this method:


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