Comment by nasretdinov

Thanks. I believe that Go indeed _could_ use those APIs to wait for the child more efficiently if they chose to, but the current implementation suggests that they're just calling wait4() in a separate thread: https://cs.opensource.google/go/go/+/refs/tags/go1.23.3:src/...

To be fair, in Go process spawning is very inefficient to begin with, since it requires lots of runtime coordination to not mess with the threads/goroutines state during fork, so running wait4() in a separate thread (although the thread can be re-used afterwards) is not the biggest concern here.