6-10 listing09.go about code HOT 9 CLOSED

I think this is the data race code. Can you put a link to the specific code you are talking about.

from code.

Thanks for reply.
URL:https://github.com/goinaction/code/blob/master/chapter6/listing09/listing09.go
The code output:

Final Counter will print 4

but the book(GO IN ACTION) says :

Final Counter will print 2

Can you fix this?
Thanks

from code.

If you are running this on Linux or the Mac, this call runtime.Gosched() will ask the scheduler to swap out the goroutine. This usually happens. I have seen on Windows the scheduler be less preemptive.

If the scheduler does not swap the goroutine, you will continue to see 4. Try this on the playground.

from code.

Oh..I running this on Mac and use go version 1.8. It output 4.
You means swap out the goroutine may depends on os?
....I cann't figure it out.

from code.

That call tells the scheduler to cooperate and allow the other goroutine to run. Basically forcing the data race. I have never seen that not work on the Mac. If you want we can jump on a ScreenHero

from code.

Check this out. https://play.golang.org/p/h9jpgaIO9F

from code.

Oh! I figure it out. Normally It output 4. I running again and again .. Finally It output2 once.
I think it always force the data race before.
And I try to use go build -race But nothing happened？

Is this expected??

from code.

The race detector should see that immediately. After you build with the race detector, you must run the program. Build does not run.

from code.

ok. I see.
Your book is very helpful.
Thanks for your patience.

from code.