On 2/18/06, Prof Brian Ripley <[EMAIL PROTECTED]> wrote: > On Sat, 18 Feb 2006, Henrik Bengtsson wrote: > > > Hi, > > > > on WinXP Pro SP2 with NTFS, I noticed that file.info() under > > Rv2.2.1pat (2006-02-09) does not report the correct file size if the > > file is >= 2^31 bytes (2GB). Is this problem known? Is this related > > to the note in ?file.info: > > > > "Some (broken) systems allow files of more than 2Gb to be created but > > not accessed by the 'stat' system call. Such files will show up as > > non-readable (and very likely not be readable by any of R's input > > functions)." > > Yes, no (although I have forgotten which file system that was). The code > relies on the stat call. On a modern OS this comes from POSIX and says > > off_t st_size; /* total size, in bytes */ > > It looks the corresponding MinGW/MSVCRT type is _off_t which is long, and > on Windows that is a 32-bit type. This can be avoided by > calling stati64 rather than stat: that is incorrectly documented in my > copy of MSDN library, but I have been able to find the correct > incantation so this will be fixed in R-devel soon.
Thank you very much for this. Regards, Henrik > > Example: > > > > # Create a 2Gb(!) file, report file.info()$size, and remove the file. > > > > fname <- "tmp.Rbin"; > > con <- file(fname, open="w+b"); > > size <- 2^31-1; # OK > > size <- 2^31; # Not OK > > seek(con, where=size-1, rw="write"); > > writeBin(con=con, as.integer(0), size=1); > > close(con); > > print(file.info(fname)$size); > > file.remove(fname); > > > > With size = c(2^31-1,2^31), file.info() reports file size > > c(2147483647,-2147483648). This looks to me like a non-signed to > > signed integer case. > > > > Note that the above code does indeed create files >2Gb on WinXP with > > NTFS; I've created files about 6Gb this way. > > > > BTW, about seek() on Windows: I noticed the warning about using > > seek() on Windows (see ?seek): "We have found so many errors in the > > Windows implementation of file positioning that users are advised to > > use it only at their own risk, and asked not to waste the R > > developers' time with bug reports on Windows' deficiencies.". Not > > going to bug report, but I haven't noticed any problems this far. > > What errors/symptoms are expected? Is regardless of file system used, > > e.g. FAT, NTFS? > > Look in the bug repository. There have been issues with text files and > with files > 2Gb, and others. > > -- > Brian D. Ripley, [EMAIL PROTECTED] > 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 > > -- Henrik Bengtsson Mobile: +46 708 909208 (+1h UTC) ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
