class Foo
def finalize
puts "finalize"
end
end
Foo.new
didn’t output anything
I tried add GC.collect, still nothing,
seemed finalize doesn’t get called?
Also, does struct has finalize?
Ultimately it just means that the GC doesn’t want/need to garbage collect that instance in this contrived example. Structs aren’t allocated by the GC so no.
class Mortals
def finalize
puts "i am #{object_id}. My life is beautiful. Goodbye!"
end
end
100000.times do
Foo.new
end
crystal build m.cr
./m | wc -l
for i in {1..5}; do ./g | wc -l; done
99600
99738
97157
99547
96646
It seems that in some cases the end of the world will come while we are still alive!
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This happens because the GC doesn’t run at program exit - if there is memory still allocated then the system is responsible for deallocating stuff, and the finalizer won’t get invoked. Finalizers should basically only be used in code dealing with C extensions that need them to help with cleaning up stuff in long running programs.
Personally I wish finalizers were run as part of shutting down, but there are a lot of potential issues around that that makes can be really hard to deal with.
1 Like
