On Wednesday, March 22, 2017 at 10:38:32 PM UTC+8, T L wrote:
>
>
>
> On Wednesday, March 22, 2017 at 7:49:39 PM UTC+8, Dave Cheney wrote:
>>
>> Well, that program isn't that simple because of the closure, but also
>> because it contains a data race
>>
>> Something like this is easier to reason about
>>
>> var x *int
>>
>> func main() {
>> var a int
>> x = &a
>> fmt.Println(*x)
>> }
>>
>
> or like this, :D
>
> package main
>
> func f(*int){
> var b int
> // avoid f to be inlined.
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> b++
> }
>
> func main() {
> var a int
> f(&a) // &a escapes to heap
> }
>
>
>
a simpler one
package main
func f(*int){
for 1 < 0 {} // avoid f to be inlined.
}
func main() {
var a int
f(&a) // &a escapes to heap
}
>
>> On Wednesday, 22 March 2017 21:59:17 UTC+11, T L wrote:
>>>
>>>
>>>
>>> On Wednesday, March 22, 2017 at 6:40:53 PM UTC+8, Jesse McNelis wrote:
>>>>
>>>> On Wed, Mar 22, 2017 at 8:51 PM, T L <[email protected]> wrote:
>>>> >
>>>> > More accurately, I think it should be: from the POV of a programmer,
>>>> it's
>>>> > globals, and things reachable from each goroutine.
>>>> >
>>>>
>>>> The only way to reach a value is through a variable in scope and the
>>>> only variables in scope are global or on the stack.
>>>>
>>>> 'heap pointers of local allocated memory blocks' are stored where ever
>>>> you put them, but you can only put them in places you can find by
>>>> using global or local stack variables.
>>>>
>>>
>>> So for this simple program:
>>>
>>> func main() {
>>> var a int
>>> go func() { // new goroutine
>>> a++
>>> }()
>>>
>>> // ...
>>> }
>>>
>>> a will be allocated on heap.
>>> a is referenced by both stack of main and the new goroutine?
>>> how is it referenced, the pointer of a's memory block is stored in both
>>> stacks?
>>>
>>
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/d/optout.
