Doesn't seem confusing at all.
RETURN VALUE
On success readv returns the number of bytes read. On
success writev returns the number of bytes written. On
error, -1 is returned, and errno is set appropriately.
ERRORS
EINVAL An invalid argument was given. For instance count
might be greater than MAX_IOVEC, or zero. fd could
also be attached to an object which is unsuit-
able for reading (for readv) or writing (for
writev).
I don't see much in the way of waffle words. If count is greater than
MAX_IOVEC or zero you get EINVAL. I suppose your next argument is if
count exceeds MAX_IOVEC a return of 0 is okay since, hopefully, nothing
was read? Where do you read a non-error return of zero is acceptable
for count of 0? I states EINVAL for a count of 0.
If your going to rework the manpage, then drop a count of 0 as an error,
otherwise fix the kernel with the trival patch.
Jim
On Mar 26, 9:01am, Balbir Singh wrote:
> Subject: Re: readv() return and errno
> I agree it is not a big thing at all, zero not
> returning any error. Yes! I read and understood the
> MAY return an error, it makes complete sense.
>
> I agree, the Linux man pages need a lot of work,
> if they are going to be even close to reflecting
> some of things in the kernel.
>
>
> Thanks,
> Balbir
>
> --- Andries.Brouwer@cwi.nl wrote:
> > Jim Hollenback wrote:
> >
> > > According to readv(2) EINVAL is returned for an
> > invalid
> > > argument.
> >
> > Right.
> >
> > > The examples given were count might be greater
> > than
> > > MAX_IOVEC or zero.
> >
> > Wrong, or at least confusingly phrased.
> >
> >
> > In the good old days, a man page described what the
> > system did,
> > and the ERRORS section gave the reasons for the
> > possible error
> > returns.
> > These days a man page describes a function present
> > on many
> > Unix-like systems, and not all systems have
> > precisely the
> > same behaviour. POSIX man pages therefore
> > distinguish under
> > ERRORS the two possibilities "if foo then this error
> > must be
> > returned", and "if foo then this error may be
> > returned".
> >
> > Linux man pages do not (yet) make this distinction -
> > adding this is a lot of careful work, and so far
> > nobody is doing this [hint..].
> > In other words, the ERRORS section in Linux man
> > pages is
> > to be interpreted as "if foo then this error may be
> > returned".
> >
> > Note that it may not be desirable at all to do
> > things that way,
> > there is no need for kernel patches, it just means
> > that systems
> > exist with this behaviour, so that authors of
> > portable programs
> > must take this into account.
> >
> > Balbir Singh wrote:
> >
> > > Apply this trivial patch, if you want the required
> > behaviour
> >
> > But the behaviour is not required.
> > Paul Larson makes the same mistake.
> >
> > Andries
>
>
> __________________________________________________
> Do You Yahoo!?
> Yahoo! Movies - coverage of the 74th Academy Awards®
> http://movies.yahoo.com/
>-- End of excerpt from Balbir Singh
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sun Mar 31 2002 - 22:00:11 EST