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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 0x7f65600711b0freeing memory at 0x7f6560070f20
freeing memory at 0x7f6560070a70
freeing memory at 0x7f65600024e0
freeing memory at 0x7f6560070640
freeing memory at 0x7f6560061670
freeing memory at 0x7f656000a040
freeing memory at 0x7f656006d560
freeing memory at 0x7f656006d540

See also

Ways to use this method:


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