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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 0x7fdefc066c90
freeing memory at 0x7fdefc00de30
freeing memory at 0x7fdefc068dc0
freeing memory at 0x7fdefc068720
freeing memory at 0x7fdefc068e70
freeing memory at 0x7fdefc068740
freeing memory at 0x7fdefc0663f0
freeing memory at 0x7fdefc066410
freeing memory at 0x7fdefc0663d0
freeing memory at 0x7fdefc068e50

Ways to use this method: