If you were to do that, yes. I guess it come to: How do you define “done” in
your program? Waitgroup defines it as when all the goroutines which it counted
are closed.
John
John Souvestre - New Orleans LA
From: golang-nuts@googlegroups.com [mailto:golang-nuts@googlegroups.com] On
Behalf Of Henrik Johansson
Sent: 2017 November 04, Sat 04:46
To: 2891132l...@gmail.com
Cc: golang-nuts
Subject: Re: [go-nuts] Re: concurrency programing about go
I find continuously adding and calling done on a waitgroup a bit odd. The
waiting goroutine can continue as soon as the count is zero so there is a race
between adds and dones.
On Sat, 4 Nov 2017, 10:01 , <2891132l...@gmail.com> wrote:
Thank you very much.Sorry I still have some question:what's the function of wg?
what does the sentense "wg.Add(2) " mean?? I found that if I change 2 into
1,the result is differnet.
在 2017年11月3日星期五 UTC+8上午4:45:47，snmed写道：
Hi
Here is the code:
Version 1:
package main
import (
"fmt"
"sync"
)
var a string
var once sync.Once
func setup() {
a = "hello,world\n"
}
func doprint() {
once.Do(setup)
fmt.Print(a)
}
func twoprint() <-chan struct{} {
var wg sync.WaitGroup
wg.Add(2)
ch := make(chan struct{})
go func() {
doprint()
wg.Done()
}()
go func() {
doprint()
wg.Done()
}()
go func() {
wg.Wait()
close(ch)
}()
return ch
}
func main() {
ch := twoprint()
<-ch
}
Version 2:
package main
import (
"fmt"
"sync"
)
var a string
var once sync.Once
func setup() {
a = "hello,world\n"
}
func doprint() {
once.Do(setup)
fmt.Print(a)
}
func twoprint() {
var wg sync.WaitGroup
wg.Add(2)
go func() {
doprint()
wg.Done()
}()
go func() {
doprint()
wg.Done()
}()
wg.Wait()
}
func main() {
twoprint()
}
Cheers snmed
Am Donnerstag, 2. November 2017 10:37:15 UTC+1 schrieb 28911...@gmail.com:
Sorry,I try my best to open the website but it can't work.Can you write it
??Thank you so much.
在 2017年10月30日星期一 UTC+8下午4:29:44，snmed写道：
Hi
There are several ways to solve it, here are two of them:
https://play.golang.org/p/wJwkI7HQwv
https://play.golang.org/p/nasUcgBeG4
I prefer the first one, because so I can decide if i want to wait for the end
of twoprint or not.
Cheers
Am Montag, 30. Oktober 2017 06:43:45 UTC+1 schrieb 28911...@gmail.com:
Yes, you're right.So how to solve it??
在 2017年10月30日星期一 UTC+8下午12:37:49，Dave Cheney写道：
Hello. I’m guessing that your tried calling twoprint(), but you’ve probably
found that nothing is printed to the screen before your program exits.
Is that correct?
--
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.
--
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.
