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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 0x7431900683b0
freeing memory at 0x7431900663f0freeing memory at 0x7431900663d0
freeing memory at 0x743190068440
freeing memory at 0x743190004b00
freeing memory at 0x743190051d00
freeing memory at 0x74319005dd10
freeing memory at 0x7431900663f0
freeing memory at 0x743190067d10
freeing memory at 0x743190068460

Ways to use this method: