On Saturday, January 28, 2017 at 10:33:08 PM UTC+8, Dave Cheney wrote:
>
>
>
> On Sunday, 29 January 2017 01:25:20 UTC+11, T L wrote:
>>
>>
>>
>> On Saturday, January 28, 2017 at 9:33:51 PM UTC+8, C Banning wrote:
>>>
>>> From the doc: "The finalizer for obj is scheduled to run at some
>>> arbitrary time after obj becomes unreachable. There is no guarantee that
>>> finalizers will run before a program exits, so typically they are useful
>>> only for releasing non-memory resources associated with an object during a
>>> long-running program."
>>>
>>
>>
>> If this is true, then the SetFinalizer function would be much meaningless.
>>
>
> Yes. The only reasonable way to interpret the operation of SetFinalizer is
> to assume it does not thing and program accordingly.
>
> To repeat, you cannot base the correct operation of your program on a
> finaliser running before your program exits.
>
I know, I just want to make sure some fanalizers will get executed for a
long running program.
But it looks the current implementation of SetFinalizer can't make any
guarantee at all.
>
>> BTW, it looks both finalizer will get executed if let the program sleep
>> more than 10us at the beginning:
>>
>> package main
>>
>> import "time"
>> import "runtime"
>>
>> func main() {
>> time.Sleep(10 * time.Microsecond)
>> // if sleep 10 Microsecond here, 2 and 1 will both be out
>> // if sleep 1 Microsecond here, still only 2 will out
>>
>> t1 := new(int)
>> t2 := new(int)
>>
>> runtime.SetFinalizer(t1, func(*int) {println(1)})
>> runtime.SetFinalizer(t2, func(*int) {println(2)})
>> runtime.GC()
>> time.Sleep(time.Second * 20)
>> }
>>
>>
>>>
>>>
>>> On Saturday, January 28, 2017 at 6:17:37 AM UTC-7, T L wrote:
>>>>
>>>>
>>>>
>>>> package main
>>>>
>>>> import "time"
>>>> import "runtime"
>>>>
>>>> type T1 struct{ i int }
>>>> type T2 struct{ i int }
>>>>
>>>> func main() {
>>>> t1 := new(T1)
>>>> t2 := new(T2)
>>>>
>>>> runtime.SetFinalizer(t1, func(*T1) {println(1)})
>>>> runtime.SetFinalizer(t2, func(*T2) {println(2)})
>>>> runtime.GC()
>>>> time.Sleep(time.Second * 2)
>>>>
>>>> // the program will output: 2
>>>> // if I adjust the order of the declarations of t1 and t2,
>>>> // the program will output: 1
>>>> }
>>>>
>>>> Why the finalizer for the first declaration will not get called?
>>>>
>>>
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