Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!columbia!rutgers!dayton!rosevax!sds!dave From: dave@sds.SciCom.MN.ORG (dave schmidt x194) Newsgroups: comp.lang.c Subject: Re: Weird syscall returns Message-ID: <430@sds.SciCom.MN.ORG> Date: Wed, 15-Jul-87 15:01:35 EDT Article-I.D.: sds.430 Posted: Wed Jul 15 15:01:35 1987 Date-Received: Sat, 18-Jul-87 03:22:40 EDT References: <1158@copper.TEK.COM> <6858@auspyr.UUCP> <17171@cca.CCA.COM> <23189@sun.uucp> Organization: SciCom Data Services Ltd., Minnetonka, MN Lines: 27 > > > I can think of no Unix system call that doesn't return -1 on error. > > > > What about nice()? > > From the S5R3 manual page: > > DIAGNOSTICS > Upon successful completion, "nice" returns the new nice > value minus 20. Otherwise, a value of -1 is returned and > "errno" is set to indicate the error. > > Other versions of "nice" may just return 0 on success, but they all > return -1 on error. How about "all reasonable versions return -1 on error"? Here in the backwaters of UNIX work-a-likes (aka XENIX), the manual says RETURN VALUE On successful completion, 'nice' returns the new nice value minue 20. Note that 'nice' is unusual in the way return codes are handled. It differs from most other system calls in two ways: the value -1 is a valid return code (in the case where the new nice value is 19), and the system call either works or ignores the request; THERE IS NEVER AN ERROR. [my emphasis] Personally, I'd regard ignoring the request as an error, but ...