This is already corrected in R-patched and R-devel: see their NEWS files.
On Fri, 23 May 2003, Laurens Leerink wrote:
> While using the file functions have found a few more issues (on both Unix
> and Windows) ie
>
> R documentation:
> In the "close" description (base package) we see that the
possible values
> for the mode 'open' the "r+" and "r+b" values
are repeated, and are
> incorrect the second time. The second set actually corresponds to the
"w+" /
> "w+b", see "man fopen" on unix.
>
> File connections:
> I had trouble using "r+" / "r+b" modes when processing
files, all files
> opened in this mode does not allow one to write to the file. Saw that the
> isOpen(con, "w") function always returns F in this mode, ie one
can read
> from them but cannot write. After experimenting with flag combinations it
> seems that all the other modes work well, so looked at the source code. If
> I'm not mistaken line 247 in connections.c should be changed from
>
> if(mlen >= 2 && con->mode[1] == '+')
con->canread = TRUE;
>
> to
>
> if(mlen >= 2 && con->mode[1] == '+')
con->canwrite = TRUE;
>
> This explained my earlier R script tests, ie that the only way to write to
a
> file is to truncate it ("w"/"w+" flag) or by appending
to it ("a"/"ab").
>
> Regards,
> Laurens
>
> > -----Original Message-----
> > From: Laurens Leerink
> > Sent: Friday, May 23, 2003 9:33 AM
> > To: 'r-help@stat.math.ethz.ch'
> > Subject: isSeekable returns F on seekable file
> >
> > Hi,
> >
> > Seems that on RWin 1.7.0 and 1.6.2 isSeekable returns F on binary
files,
> > while seek() works as expected on the same connection - see example
below:
> >
> > > con = file(nm, "rb")
> > > isSeekable(con)
> > [1] FALSE
> > > readBin(con, double(), 10)
> > [1] 7.263824e-317 5.968155e-317 2.340685e-317 2.734062e-312
4.088386e-312
> > 4.670335e-317
> > [7] 6.097545e-317 3.396341e-312 6.615484e-317 1.365171e-312
> > > readBin(con, double(), 10)
> > [1] 1.303796e-317 5.577835e-317 3.409314e-312 1.303543e-317
3.893617e-317
> > 4.077940e-312
> > [7] 6.910006e-313 2.694357e-318 4.088373e-312 6.484955e-317
> > > seek(con, 0, origin="start")
> > [1] 160
> > > readBin(con, double(), 10)
> > [1] 7.263824e-317 5.968155e-317 2.340685e-317 2.734062e-312
4.088386e-312
> > 4.670335e-317
> > [7] 6.097545e-317 3.396341e-312 6.615484e-317 1.365171e-312
> > >
> >
> > Am I doing something silly or is the function returning the wrong
value?
> >
> > Regards,
> > Laurens Leerink
>
> [[alternate HTML version deleted]]
>
> ______________________________________________
> R-devel@stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-devel
>
--
Brian D. Ripley, ripley@stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595