On Wed, Apr 3, 2019 at 11:50 PM <mountain...@gmail.com> wrote: > > hehe, thanks, so if i want understand deeply, need to look up gc code?
No, the language spec is at https://golang.org/ref/spec. Ian > 在 2019年4月3日星期三 UTC+8下午10:34:57，Ian Lance Taylor写道： >> >> On Wed, Apr 3, 2019 at 6:32 AM <mount...@gmail.com> wrote: >> > >> > thanks! v must be a value copy，Is this determined by the compiler? >> >> It's determined by the language definition. >> >> Ian >> >> >> > 在 2019年4月3日星期三 UTC+8下午7:57:26，Marvin Renich写道： >> >> >> >> * mount...@gmail.com <mount...@gmail.com> [190403 05:10]: >> >> > package main >> >> > >> >> > func main() { >> >> > b := []int{1} >> >> > >> >> > bb := make([]*int, 0, 1) >> >> > for k, v := range b { >> >> >> >> The above range clause will assign to k the index of the current >> >> element, and it will assign to v a copy (as if v = b[k]) of the element >> >> at that index. >> >> >> >> Go does not have references of the kind that C++ or Java has, so v >> >> cannot be a reference, in that sense, to b[k]; it must be a value copy. >> >> >> >> If what you really want is to be able to refer to the location of the >> >> element in the slice (really its backing array), omit the v in the range >> >> clause and just use &b[k]: >> >> >> >> for k := range b { >> >> _ = &b[k] // do what you want >> >> } >> >> >> >> > _ = &v //8 line >> >> > _ = &b[k] //9 line >> >> > // bb = append(bb, &v) >> >> > bb = append(bb, &b[k]) >> >> > } >> >> > >> >> > // for _, v := range bb { >> >> > // fmt.Println(*v) >> >> > // } >> >> > } >> >> >> >> ...Marvin >> >> >> > -- >> > 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 golan...@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.
