Path: utzoo!attcan!uunet!husc6!uwvax!oddjob!kaon!nucsrl!naim From: naim@eecs.nwu.edu (Naim Abdullah) Newsgroups: comp.unix.wizards Subject: Is write(2) "atomic" ? Message-ID: <11410005@eecs.nwu.edu> Date: 12 Jul 88 10:12:23 GMT Organization: Northwestern U, Evanston IL, USA Lines: 17 Do UNIX semantics guarantee that write(2) calls will be "atomic" ? Suppose, process A executes write(fd, "123", 3) and process B executes write(fd, "456", 3) "concurrently". The file descriptor fd is shared between them (the file was creat(2)'ed for writing by the common parent of A and B). Does UNIX guarantee that the contents of the descriptor will be "123456" or "456123" (depending on which of A and B won the race) but never "124536" ? Does it make a difference whether the descriptor is a pipe or a terminal or a disk file or a tape drive or something else ? Naim Abdullah Dept. of EECS, Northwestern University Internet: naim@eecs.nwu.edu Uucp: {oddjob, chinet, gargoyle}!nucsrl!naim