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From: C.DeRykus on 12 Aug 2010 15:01
On Aug 12, 8:04 am, "Peter J. Holzer" <hjp-usen...(a)hjp.at> wrote:
> On 2010-08-10 22:16, Martijn Lievaart <m...(a)rtij.nl.invlalid> wrote:
>
>
>
> > On Tue, 10 Aug 2010 00:20:34 -0700, Marc Girod wrote:
> >> On Aug 9, 6:32 pm, Martijn Lievaart <m...(a)rtij.nl.invlalid> wrote:
....
> > or implement some sort of locking
> > mechanism.
>
> O_EXCL is "some kind of locking mechanism": Any already existing file is
> "locked" and won't be overwritten. It doesn't wait (wouldn't be very
> useful since files aren't deleted) but fails immediately. Then the
> program tries a new file name. This looks ok (it is also a usual method
> for creating temporary files). Maybe the "try next file filename" part
> doesn't work correctly - we haven't seen the code and it probably isn't
> well tested.

It's not clear to me what O_EXCL will do though
since the files are remote and the OP's doc say:

"O_EXCL" may not work on network filesystems ...

This makes me wonder if "not work" might well
manifest as a flurry of false positives for
an error at times but work normally at other
times.

I don't know if there are other network locking
mechanisms that'd be easy or reliable though.

--
Charles DeRykus
From: Peter J. Holzer on 12 Aug 2010 16:03
On 2010-08-12 19:01, C.DeRykus <derykus(a)gmail.com> wrote:
> It's not clear to me what O_EXCL will do though
> since the files are remote and the OP's doc say:
>
> "O_EXCL" may not work on network filesystems ...
>
> This makes me wonder if "not work" might well
> manifest as a flurry of false positives for
> an error at times but work normally at other
> times.

I already covered this in my first posting in this thread. If you can
add anything substantial to that, please do.

hp

From: C.DeRykus on 12 Aug 2010 18:31
On Aug 12, 1:03 pm, "Peter J. Holzer" <hjp-usen...(a)hjp.at> wrote:
> On 2010-08-12 19:01, C.DeRykus <dery...(a)gmail.com> wrote:
>
> > It's not clear to me what O_EXCL will do though
> > since the files are remote and the OP's doc say:
>
> >    "O_EXCL" may not work on network filesystems ...
>
> > This makes me wonder if "not work" might well
> > manifest  as a flurry of false positives for
> > an error at times but work normally at other
> > times.
>
> I already covered this in my first posting in this thread. If you can
> add anything substantial to that, please do.
>

I must've missed it. I did see the remark that
'it's very likely that “File exists” is set by
sysopen' without explicit mention of sysopen not
being guaranteed to work over the network.

--
Charles DeRykus


From: C.DeRykus on 13 Aug 2010 00:23
On Aug 12, 9:16 pm, Michael Vilain <vil...(a)NOspamcop.net> wrote:
> In article
> <02884f9f-4127-40d7-8474-6a40b35b0...(a)a4g2000prm.googlegroups.com>,
>
>
>
>  "C.DeRykus" <dery...(a)gmail.com> wrote:
> > On Aug 12, 1:03 pm, "Peter J. Holzer" <hjp-usen...(a)hjp.at> wrote:
> > > On 2010-08-12 19:01, C.DeRykus <dery...(a)gmail.com> wrote:
>
> > > > It's not clear to me what O_EXCL will do though
> > > > since the files are remote and the OP's doc say:
>
> > > >    "O_EXCL" may not work on network filesystems ...
>
> > > > This makes me wonder if "not work" might well
> > > > manifest  as a flurry of false positives for
> > > > an error at times but work normally at other
> > > > times.
>
> > > I already covered this in my first posting in this thread. If you can
> > > add anything substantial to that, please do.
>
> > I must've missed it. I did see the remark that
> > 'it's  very likely that ³File exists² is set by
> > sysopen' without explicit mention of sysopen not
> > being guaranteed to work over the network.
>

>
> I've been following this thread since it started.  This is the first
> mention of the file being on a networked filesystem.

See the original post:

"The script does write to a network filesystems
(home directory on a remote filer, 4 ms round-trip)."

--
Charles DeRykus
From: Peter J. Holzer on 13 Aug 2010 14:32
On 2010-08-12 22:31, C.DeRykus <derykus(a)gmail.com> wrote:
> On Aug 12, 1:03�pm, "Peter J. Holzer" <hjp-usen...(a)hjp.at> wrote:
>> On 2010-08-12 19:01, C.DeRykus <dery...(a)gmail.com> wrote:
>> > It's not clear to me what O_EXCL will do though
>> > since the files are remote and the OP's doc say:
>>
>> > � �"O_EXCL" may not work on network filesystems ...
>>
>> > This makes me wonder if "not work" might well
>> > manifest �as a flurry of false positives for
>> > an error at times but work normally at other
>> > times.
>>
>> I already covered this in my first posting in this thread. If you can
>> add anything substantial to that, please do.
>>
>
> I must've missed it.

<slrni5qj95.jq5.hjp-usenet2(a)hrunkner.hjp.at>

hp

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