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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 0x7eff840712f0
freeing memory at 0x7eff84070fe0
freeing memory at 0x7eff84006fa0
freeing memory at 0x7eff84071290
freeing memory at 0x7eff840712b0
freeing memory at 0x7eff8406f1d0
freeing memory at 0x7eff840718c0
freeing memory at 0x7eff84071000
freeing memory at 0x7eff84070bb0

See also

Ways to use this method:


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