On Wed, Dec 18, 2013 at 11:40 PM, erik quanstrom <quanstro@quanstro.net>wrote:
>
>
> to be more explicit.  if a is built from b and mtime(a) <= mtime(b), then
> mk could fail to rebuild a when it needs to.  for correctness, mk must
> use <=
> not <.
>

I was thinking about the problem and actually, at least in all
circumstances I can think of, changing that one operation from <= to <
would fix the problem.  If the times are on the same second, I would never
have had time to change it.  This would fix the problem.  Perhaps this
functionality can be controlled by an environment variable like NPROC.

I think this is important as follows.  If you are working on a project,
edit some files, and then perform a mk, if files you haven't changed get
built, I for one would constantly question myself, about whether or not I
changed that file.  It would make things confusing.  Also, and perhaps more
importantly, it may occur that a very long build is dependant on a very
short preceding build.  So, the unnecessary rebuild of the fast process can
unnecessarily trigger the very long process.  This really needs addressing
for that reason especially IMO.

Thanks.

Blake