Good point. Since you asked, I did some more reading. My bug report should have included "on 32 bit linux systems". And, it's possible to get stat to work for large files by using the correct defines. There could be linking problems if you do, but it's not likely to be a big concern. So, consider this a robustness patch. This will make exists () work on large files, even for goobers like me that don't have their compile set up to support large files. If you were extremely interested in supporting all configurations, there are also certain defines that can be set which cause large file support to be offered through an alternate set of function names, which can be useful for maintaining binary compatibility with pre-compiled libraries. Using that define and the alternate names would be a safe way to make the filesystem library work on 64bit files no matter what defines are used to compile. But, it's probably not worth the hassle if no one has complained yet. The linux gazette article at www.linuxgazette.com/issue67/tag/13.html was interesting, if you want to follow up on this. But, it basically said to read info on libc and look for LFS or large file support. Doing so was also interesting. --Jonathan Beman Dawes wrote:
At 01:35 AM 2/9/2004, Jonathan Ultis wrote:
::exists is implemented using ::stat. The ::stat routine returns an error on file sizes larger than 2 gigs in libc-2.3.2, and several others. So, very large files never exists (). Using ::access seems to fix the problem.
Good grief! Are you saying that ::stat() cannot be used at all because it fails for all uses when file sizes are larger than 2 gigs?
That would be a disaster. The filesystem library uses stat in at least 6 other places. I would guess that stat() is one of the most heavily used POSIX functions dealing with files, and that software from here to Antarctica to Mars would fail regularly if stat() failed for large files. Hum... Didn't I just hear something about filesystems on Mars:-?
I don't mean to doubt your report, but it seems hard to believe that such a commonly used function could fail for large files. Is there more to the story?
--Beman
PS: Your suggestion to use access() seems quite reasonable and harmless for exists(), but I haven't looked at the other filesystem uses to see if it could be uniformly applied.
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