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Packages » ForeignFunctions :: registerFinalizer(ForeignObject,Function)
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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 0x7f68e00685e0
freeing memory at 0x7f68e005df40
freeing memory at 0x7f68e0051f30
freeing memory at 0x7f68e0004f20
freeing memory at 0x7f68e0068670
freeing memory at 0x7f68e0066600
freeing memory at 0x7f68e0068690
freeing memory at 0x7f68e0067f40
freeing memory at 0x7f68e0066620

Ways to use this method: