Yes like Jan previously said. It is the very use case WaitGroup was
developed for.
On Sun, Aug 21, 2016, 15:45 T L <tapir....@gmail.com> wrote:
>
>
> On Saturday, August 20, 2016 at 2:29:41 PM UTC+8, Yulrizka wrote:
>>
>> Dear gophers
>>
>> I have discussion with my colleague about this code
>>
>>
>> func process() *foo {
>> var result *foo
>>
>> var wg sync.WaitGroup
>> wg.Add(1)
>> go func() {
>> defer wg.Done()
>> result = &foo{1}
>> }()
>>
>> wg.Wait()
>>
>> return result
>> }
>>
>> He argues that this is heap race condition.
>> the result variable which lives on the heap of the go routine is not
>> guaranteed to be synced to the result on the process func's thread.
>> The better approach would be using a channel instead. I may agree with
>> him that probably using channel is better.
>> But I would like to understand the reasoning behind that.
>>
>
> If the program is not race free, then what is the meaningfulness of
> WaitGroup?
>
>
>
>
>>
>> I thought that `wg.Wait()` guaranteed that the process func's thread wait
>> until go func is finsihed and sync everything so that the result variable
>> is safe to return.
>>
>> Probably I'm missing some knowledge about how go routine work.
>>
>> 1. Does the process func thread has separate heap than the go func? If so
>> how does is sync?
>> 2. From I read so far, when go routine needed a bigger stack, it
>> allocates memory from the heap. So what happened for object that is
>> allocated inside of the go routine once the go routine returns?
>>
>> I there article of source that go into details about this I would love to
>> read it :)
>>
>> Warm regards,
>>
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