Re: GP Makefile compiling twice

[Karim BELABAS <Karim.Belabas@math.u-psud.fr>]

On Thu, 18 Apr 2002, Bill Allombert wrote:
> On Thu, Apr 18, 2002 at 02:55:36PM +0200, Karim BELABAS wrote:
> > On Wed, 17 Apr 2002, Michael Somos wrote:
> > > I am using the latest CVS and following the recommended instructions
> > > for making the gp software. However, I notice that it seems to be
> > > compiling the source twice. In summary, I do './Configure' ,'make gp',
> > > and 'make install'.
> > >
> > It is not a feature, and I believe the Makefile is correct. Apparently, your
> > OS attaches incorrect timestamps to the some object files, and 'make'
> > believes that a header file has been modified since GP was last compiled.
> >
> > I've seen this happen on specific machines, often in conjunction with
> > messages of the form:
> >
> > gmake: *** Warning: File `../src/basemath/alglin1.c' has modification time in the future
> >
> > but could not solve it. I don't know whether to blame 'make' or the system
> > clock.  In practice, on my afflicted Linux box (i686, 2.4.7-10, RH 7.2,
> > gmake-3.79.1), it happens rarely, and only once if at all [ i.e further
> > 'make' behave as expected ].  I once had access to an ancient alpha (under
> > OSF), where this annoying behaviour was systematic: invoking make at any
> > time resulted in full recompilation (in this case, I believe the culprit was
> > 'make').
>
> For me it had always happened on NFS mounted disk, when the sysadmins do
> not setup NTP to synchronize clocks between servers and clients.
>
> If it really happen with local disks, then maybe there is a strange bug in
> the makefile.

The Linux box mentioned above has a local disk. But I definitely can't
reproduce the problem at will. I see it happen maybe once a week (and
recompile PARI every hour or so). Usually only a few extra files are
recompiled.

    Karim.
-- 
Karim Belabas                    Tel: (+33) (0)1 69 15 57 48
Dép. de Mathematiques, Bat. 425  Fax: (+33) (0)1 69 15 60 19
Université Paris-Sud             Email: Karim.Belabas@math.u-psud.fr
F-91405 Orsay (France)           http://www.math.u-psud.fr/~belabas
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