[1248] in Athena Bugs
Re: updating mod time of files
daemon@ATHENA.MIT.EDU (John T Kohl)
Wed Oct 26 09:04:05 1988
Date: Wed, 26 Oct 88 09:03:46 EDT
From: John T Kohl <jtkohl@ATHENA.MIT.EDU>
To: geer@ATHENA.MIT.EDU, bugs@ATHENA.MIT.EDU
In-Reply-To: bugs:[1246]
The stat(2) man page has this to say about the various timestamps on
files:
st_atime Time when file data was last read or modified.
Changed by the following system calls: mknod(2),
utimes(2), read(2), and write(2). For reasons
of efficiency, st_atime is not set when a direc-
tory is searched, although this would be more
logical.
st_mtime Time when data was last modified. It is not set
by changes of owner, group, link count, or mode.
Changed by the following system calls: mknod(2),
utimes(2), write(2).
st_ctime Time when file status was last changed. It is
set both both by writing and changing the i-
node. Changed by the following system calls:
chmod(2) chown(2), link(2), mknod(2), rename(2),
unlink(2), utimes(2), write(2).
So we see that open(2) does NOT change the atime, mtime or ctime fields;
you must read(2) or write(2) or play games to get times to change.
cat >> foo; ^D does not write to the file, therefore the mod time
doesn't change.
John
