[Bug-gnulib] Re: Bug#202243: glibc utimes glitch with coreutils 'touch'

[GOTO Masanori]

At 18 Aug 2003 13:30:24 -0700,
Paul Eggert wrote:
> Historically, time-related code has always truncated.  For example,
> the time() system call, "ls -l", and "date" all truncate.  There are
> good reasons for preferring truncation to rounding in timestamps,
> despite the greater numeric error.  For example, truncating makes it
> easier to answer the question "Was that file modified before
> midnight?" when you are looking at lower-resolution timestamps.  And
> double-truncation is exact, whereas double-rounding can introduce
> extra errors.
> 
> When 'utimes()' rounds, it can break applications like 'cp -p' and
> 'make', because it can cause file timestamps to be in the future
> when the timestamps are copied from just-created files.

Exactly.  I fully agreed with your opinion.  I applied.

> The current coreutils CVS works around this problem by avoiding
> 'utimes' if it detects that 'utimes' rounds.  This is unfortunate,
> because it disables support for sub-second timestamps in 'cp -p' under
> glibc; but at least it doesn't break 'make'.
> 
> Please fix this problem by applying the patch in
> <http://sources.redhat.com/ml/libc-alpha/2003-08/msg00062.html>.
> That will enable coreutils 'cp' to support sub-second timestamps.

Jakub, please take care this problem and show the flag to apply Paul's
patch?  I believe there are no point to object his patch.

Regards,
-- gotom