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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 0x7fdbc80639d0
freeing memory at 0x7fdbc8066c50
freeing memory at 0x7fdbc805f3f0
freeing memory at 0x7fdbc8063bc0
freeing memory at 0x7fdbc806a210
freeing memory at 0x7fdbc80639f0
freeing memory at 0x7fdbc806a230
freeing memory at 0x7fdbc8069180
freeing memory at 0x7fdbc8063bf0

See also

Ways to use this method: