No, you can fork, what you can’t do is “fork and then try to keep running after the fork”. That’s never really been a supported model on Darwin, and in recent y

No, you can fork, what you can’t do is “fork and then try to keep running after the fork”. That’s never really been a supported model on Darwin, and in recent years with more threading occurring it fails faster than it did in the past. On Darwin there is very little you can safely do in the child after fork(), essentially the only thing guaranteed to work at that point is exec() and a few other basic operations. Again, this has always been the case for fork under Darwin, the only difference is that you are more likely to fail sooner now than 20 years ago. This is also why all documentation says to use posix_spawn: fork +exec is necessarily slower, and can’t really do anything that posix spawn doesn’t.