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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 0x7f1b3c04f870
freeing memory at 0x7f1b3c04f5c0
freeing memory at 0x7f1b3c048a20
freeing memory at 0x7f1b3c04f5e0
freeing memory at 0x7f1b3c04fe50
freeing memory at 0x7f1b3c04ff10
freeing memory at 0x7f1b3c04f620
freeing memory at 0x7f1b3c04f850
freeing memory at 0x7f1b3c048a00

Ways to use this method: