On Thu, Jun 6, 2013 at 5:29 PM, E.S. Rosenberg <[email protected]>wrote:
> re:all, forgot to change my from field. > > 2013/6/6 Erez D <[email protected]>: > > > > > > > > On Thu, Jun 6, 2013 at 5:04 PM, E.S. Rosenberg <[email protected]> wrote: > >> > >> 2013/6/6 Erez D <[email protected]>: > >> > > >> > > >> > > >> > On Tue, Jun 4, 2013 at 6:09 PM, Shachar Shemesh <[email protected]> > >> > wrote: > >> >> > >> >> On 04/06/13 15:28, Erez D wrote: > >> >> > >> >> thanks, > >> >> > >> >> so i guess if i use unidirectional connection, and the reader does > not > >> >> expect to get an EOF() > >> >> thank i'm safe. > >> >> > >> >> Why are you so keen on doing it wrong? > >> >> > >> >> No, you are not safe. If the child process dies because of a > >> >> segmentation > >> >> fault (or whatever), the parent will notice this through the EOF > >> >> received (I > >> >> am assuming here, since you couldn't be bothered with closing a file > >> >> descriptor, that you did not install a SIGCHLD handler to monitor for > >> >> this > >> >> possibility). This means that should one process die unexpectedly, > the > >> >> other > >> >> will hang forever. > >> > > >> > it's not a matter of being bothered. closing a file has it's > >> > implications > >> > > >> > 1. close the file for one thread closes for all > >> thread and fork are 2 very different things, best practice for fork > >> ('full' children, I think everyone understands fork() when you say > >> child) is to close, when using threads that is I believe not the case. > >> > 2. what if i want later children using the same pipe, as in all childs > >> > write > >> > to same pipe read by parent... > >> so the children are all closing the read end and the parent only > >> closes write, where is the problem? > > > > if the parent closes the "write" side, then new forked children have > their > > "write" side already closed. > That's why we are able to check if we are a child or a parent with the > fork() function. > that doesn't help sunday: parent creates a pipe monday: parent forks for child 1. parent closes write. child 1 closes read. child 1 now can write and parent can read. tuesday: parent forks for child 2. child 2 can not write - pipe already close by parent on monday. > >> > >> > > >> >> > >> >> Best practices are there for a reason, despite what others here might > >> >> have > >> >> you think. > >> >> > >> >> Shachar > >> > > >> > > >> > > >> > _______________________________________________ > >> > Linux-il mailing list > >> > [email protected] > >> > http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il > >> > > > > > >
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