next | previous | forward | backward | up | top | index | toc | Macaulay2 website
ForeignFunctions :: registerFinalizer(ForeignObject,Function)

registerFinalizer(ForeignObject,Function) -- register a finalizer for a foreign object



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 0x7fc86004efd0
freeing memory at 0x7fc86004f620
freeing memory at 0x7fc86004f8b0
freeing memory at 0x7fc86004f890
freeing memory at 0x7fc86004ff50
freeing memory at 0x7fc86004fe90
freeing memory at 0x7fc86004f660
freeing memory at 0x7fc86004f600
freeing memory at 0x7fc860050060

Ways to use this method: