Re: Linux 2.6 nanosecond time stamp weirdness breaks GCC build

[Paul Eggert <eggert@CS.UCLA.EDU>]

Jamie Lokier <jamie@shareable.org> writes:

> pathconf() and fpathconf() are the obvious POSIXy interfaces for it.
> Other possibilities are getxattr(), lgetxattr() and fgetxattr().

I didn't know about getxattr etc.  They would work too.

> The only thing I don't like is that some cacheing algorithms will need
> to make 2 system calls for each file being checked, instead of 1.

Do you mean for mtime versus atime (versus ctime)?  Yes, in that case
getxattr etc. would be a better choice.

How hard would this be to do?  (Is it something you can do?  :-)

Coreutils CVS assumes that the time stamp resolution is the same for
all files within the same file system.  Is this a safe assumption
under Linux?  I now worry that some NFS implementations might violate
that assumption, if a remote host is exporting several native file
systems, with different native resolutions, to the local host under a
single mount point.  On the other hand, NFSv3 and NFSv4 clearly state
that the time stamp resolution is a per-filesystem concept, so perhaps
we should just consider that to be a buggy NFS server configuration.

> Is there a de facto standard interface used by another OS for this?

Not as far as I know, no.