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ForeignFunctions :: registerFinalizer(ForeignObject,Function)

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 0x7fa0e404f850
freeing memory at 0x7fa0e40489a0
freeing memory at 0x7fa0e404e9c0
freeing memory at 0x7fa0e404f7c0
freeing memory at 0x7fa0e404f880
freeing memory at 0x7fa0e404f4e0
freeing memory at 0x7fa0e40075b0
freeing memory at 0x7fa0e404f1c0
freeing memory at 0x7fa0e404f830

Ways to use this method: