Chapter 4: Groups & Semaphores | Semaphores section.
Page 39 v0.2 says:
You’ve already seen the read/write pattern to limit access to a single thread.
I’m not sure where this was mentioned, or said how to limit access to a single thread. Would you please elaborate more on that?
Is that when when blocking the current thread of execution using sync? maybe group.wait(timeout:)?
Thanks!
@mennabah It would appear that part of a chapter has fallen off. I’ll have to search through my notes to see where I moved it to and get that fixed up. Thanks for pointing out the issue!
@mennabah OK, finally found it. It’s about 4 pages later, just before the “Thread barrier” section in Chapter 5. We reordered a bunch of chapters and this appears to have been a casualty. We’ll get this fixed up before the next push of the early access.
Thanks @gargoyle, found it 
I would like to know how’s the book? Should I purchase it?
Table of content is good, but not all of them are available in the current version since it’s still in beta. However, concurrency is a good topic to master, and the final release should be out by fall.
The full book is now available on the store!