The only real rule is "when the compiler can prove, that it doesn't escape,
it doesn't". There is no guarantee or fixed policy around escape analysis.
If you are convinced that something doesn't escape and that the compiler
should be able to figure it out, you can try filing an issue about that
with the code and output of -gcflags=-m.
On Fri, Sep 30, 2016 at 5:20 AM, 刘桂祥 <liuguixiang...@gmail.com> wrote:
> package main
>
> func main() {
> var m map[int]int
>
> {
> m = make(map[int]int)
> }
>
> _ = m
> }
>
> if I do this m will not escape just want to know what's the scope rule for
> escape ? puzzled
> <http://www.baidu.com/link?url=ApC817U9uUoCFHhS_dqb5JzUWJQsslUUA6_TDv3LDZBJgaA-G2ZbRfWA-2cGajgU_MHmTiXVEouMmdPN53mMMXxYd1nvCWWJJvfu5Mmg4Ca>
>
>
> 在 2016年9月29日星期四 UTC+8上午1:39:09，Chris Manghane写道：
>>
>> In the first example, make does not escape the scope of the for
>> statement. In the second example, make is assigned to m, which is outside
>> of the scope of the for statement, which means the make operation escapes
>> its scope and subsequently, is heap allocated. If you want more information
>> about why something escapes, try compiling with -gcflags "-m -m" for an
>> explanation of the escape analysis information.
>>
>> On Wed, Sep 28, 2016 at 7:56 AM, 刘桂祥 <liuguix...@gmail.com> wrote:
>>
>>> go 1.7
>>>
>>> 在 2016年9月28日星期三 UTC+8下午10:41:09，Dave Cheney写道：
>>>
>>>> Which version of Go?
>>>>
>>>> On Thursday, 29 September 2016 00:18:29 UTC+10, 刘桂祥 wrote:
>>>>>
>>>>> // example1.go
>>>>> package main
>>>>>
>>>>>
>>>>> func main() {
>>>>>
>>>>> for i := 0; i < 2; i++ {
>>>>> m := make(map[int]int)
>>>>>
>>>>>
>>>>> m[1] = 100
>>>>> }
>>>>>
>>>>>
>>>>> }
>>>>>
>>>>>
>>>>> main make(map[int]int) does not escape
>>>>>
>>>>>
>>>>> // example2.go
>>>>> package main
>>>>>
>>>>>
>>>>> func main() {
>>>>> var m map[int]int
>>>>> for i := 0; i < 2; i++ {
>>>>> m = make(map[int]int)
>>>>>
>>>>>
>>>>> m[1] = 100
>>>>> }
>>>>>
>>>>>
>>>>> }
>>>>>
>>>>> make(map[int]int) escapes to heap why ???
>>>>>
>>>>>
>>>>> --
>>> 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 golang-nuts...@googlegroups.com.
>>> For more options, visit https://groups.google.com/d/optout.
>>>
>>
>> --
> 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 golang-nuts+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
>
--
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 golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
