On Wed, Jun 15, 2011 at 06:11:31PM +0100, Philip Martin wrote:
> pet...@apache.org writes:
>
> > Author: peters
> > Date: Wed Jun 15 16:43:24 2011
> > New Revision: 1136114
> >
> > URL: http://svn.apache.org/viewvc?rev=1136114&view=rev
> > Log:
> > * configure.ac: Followup r1134219: Use 'cmp -s' instead of 'diff' to
> > detect changes to svn_private_config.h. Take advantage of the fact
> > that cmp -s produces no output even if a file does not exist.
> > Use a temp variable to shorten the lines further.
>
> Is cmp as portable as diff? Is it always available with the same
> behaviour? autoconf generates calls to diff, so we know that using diff
> will work anywhere that autoconf works. As far as I can tell autoconf
> doesn't use cmp.
>From the cmp man page:
HISTORY
"A cmp command appeared in Version 1 AT&T UNIX."
I would say that's ancient enough to be supported anywhere :)
Oh, and it also conforms to POSIX.
