Date: Sun, 28 Dec 2008 07:35:28 -0900 From: Mel <fbsd.questions@rachie.is-a-geek.net> To: freebsd-questions@freebsd.org Cc: Mitar <mmitar@gmail.com>, Jonathan Chen <jonc@chen.org.nz> Subject: Re: Open with O_APPEND fails Message-ID: <200812280735.28751.fbsd.questions@rachie.is-a-geek.net> In-Reply-To: <20081228060658.GA73070@osiris.chen.org.nz> References: <f63c4b2d0812271246u18a881e6j87e0054c24f4661a@mail.gmail.com> <f63c4b2d0812272046x3977f7d6q7fb1305164db973b@mail.gmail.com> <20081228060658.GA73070@osiris.chen.org.nz>
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On Saturday 27 December 2008 21:06:58 Jonathan Chen wrote:
> On Sun, Dec 28, 2008 at 05:46:39AM +0100, Mitar wrote:
> > Hi!
> >
> > On Sun, Dec 28, 2008 at 5:10 AM, Mel
> >
> > <fbsd.questions@rachie.is-a-geek.net> wrote:
> > > open(2) will succeed but write(2) will fail with EBADF as documented
> > > (and I verified this behavior). Still no EACCES as you and the
> > > bugreporter are seeing.
> >
> > Where is documented that write would fail if file is opened only with
> > O_APPEND?
Implicitly in write(2) manpage:
The write(), writev(), pwrite() and pwritev() system calls will fail and
the file pointer will remain unchanged if:
[EBADF] The d argument is not a valid descriptor open for
writing.
> > Just O_APPEND should also open file for writing as appending
> > is also writing. It cannot be used without "write" semantics so file
> > has to be open also for writing.
>
> If I recall correctly, this behaviour has been standard on UNIX-like
> OS's for a *very* long time now. If you are seeing a write allowed
> with just O_APPEND on Linux, it would very likely be a Linux only
> "feature".
Yup. Append is a bad english choice for the constant as it implies writes like
you say, but really should be O_ATEND, because that's all that it does: seek
to EOF.
--
Mel
Problem with today's modular software: they start with the modules
and never get to the software part.
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