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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 0x7fffd8063af0
freeing memory at 0x7fffd806a130
freeing memory at 0x7fffd806a110
freeing memory at 0x7fffd80638f0
freeing memory at 0x7fffd805f2f0
freeing memory at 0x7fffd8063ac0
freeing memory at 0x7fffd80638d0
freeing memory at 0x7fffd8069080
freeing memory at 0x7fffd8066b50

See also

Ways to use this method: