martin@clubmed.hf.intel.com.ogc.edu (12/30/89)
Does anyone know what the O_EXCL flag for the open call is supposed to do? I have read the POSIX spec, but I don't quite understand what the flag is for. The only thing that the POSIX spec says is that if O_EXCL and O_CREAT are set, open() shall fail if the file exists. What if just O_EXCL is set? You can mail to me directly or post a followup... Thanks... _/_ | ______ __. __ / o ____ | textronix!reed!littlei!zeus:martin / / / <_(_/|_/ (_<__<_/ / < | | martin@clubmed.hf.intel.com |
lm@snafu.Sun.COM (Larry McVoy) (12/30/89)
In article <479@dios.hf.intel.com> martin@clubmed.hf.intel.com (Martin Wilde) writes: >Does anyone know what the O_EXCL flag for the open call is >supposed to do? I have read the POSIX spec, but I don't quite >understand what the flag is for. The only thing that >the POSIX spec says is that if O_EXCL and O_CREAT are set, open() >shall fail if the file exists. What if just O_EXCL is set? Yeah, it's a misnomer. As far as I know, it's only generic use is the one you describe (commonly used to implement a crude form of semaphore). I think that some device drivers may also look at this flag to mean exclusive (i.e, one user). --- What I say is my opinion. I am not paid to speak for Sun, I'm paid to hack. Larry McVoy, Sun Microsystems (415) 336-7627 ...!sun!lm or lm@sun.com