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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 0x3ff84066390
freeing memory at 0x3ff8400de30
freeing memory at 0x3ff84068700
freeing memory at 0x3ff840686e0
freeing memory at 0x3ff84066c50
freeing memory at 0x3ff840663d0
freeing memory at 0x3ff84068d80
freeing memory at 0x3ff84068e10
freeing memory at 0x3ff840663b0

Ways to use this method: