On Saturday, 29 February 2020 12:37:24 UTC, Ian Lance Taylor wrote: > > On Sat, Feb 29, 2020 at 12:33 AM Brian Candler <b.ca...@pobox.com > <javascript:>> wrote: > > > > Just to ask the an obvious question: is dup2() idempotent or not? > > dup2 in itself is idempotent. But I'm not sure that is a useful > question.
I think it makes sense in the context of the question "should I repeat dup2() if it returns with EINTR?" If it's idempotent, then it's safe to do so. > The issue is whether some other thread in the same process > can open a file at the target file descriptor between calls to dup2. To put it another way, dup2 is idempotent, but if you make multiple > calls to dup2, the order in which you make those calls matters. I don't quite follow. If two threads are fighting to use the target fd, then that's just a race anyway. fds are a global resource; if one thread is doing (say) dup2(3,10), then it must already be sure that fd 10 is available globally, i.e. it won't be stomping on any other thread using fd 10. -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/b6df168f-dd7c-4a37-a52e-e4cdc2fb29cb%40googlegroups.com.
