Re: ar "zero" flag

["Perry E. Metzger" <perry%piermont.com@localhost>]

David Holland <dholland-tech%netbsd.org@localhost> writes:
> On Tue, Aug 05, 2008 at 03:04:48PM +0200, Joerg Sonnenberger wrote:
>  > > Several people, including cgd, have independently suggested that a
>  > > flag to ar that said "zeroize the time, uid, etc., on packing" would
>  > > be appropriate.
>  > 
>  > I don't like it as it removes any knowledge when a file was build.
>  > It doesn't matter for updates as long as the content didn't change, but
>  > removing it completely is bad.
>
> I don't think I've ever run into a reason to care about the timestamps
> of the innards of .a files.

In theory, they have a function.

Back in the days when it took a very long time to build a .a file
up from sources, it was valuable during development to allow make to
do dependency analysis based on the time stamps of objects inside the
ar files. That way you could compile just the one .c file you altered,
and replace the .o inside the .a file, all automatically.

I don't intend to break that functionality per se although it is long
obsolete. This will only impact system .a files built with build.sh --
user built .a files won't be touched. If you use build.sh, a special
flag will be called on ar, so that the .a files are built
bit-reproduceable.


-- 
Perry E. Metzger                perry%piermont.com@localhost