[petsc-dev] Fwd: [petsc-users] cannot find 'libz.a' when configuring

[Matthew Knepley]

On Thu, Apr 11, 2013 at 10:12 AM, Satish Balay <balay at mcs.anl.gov> wrote:

> On Thu, 11 Apr 2013, Satish Balay wrote:
>
> > > > > > > We have had this same discussion a million times, and we always
> > > > > > eventually
> > > > > > > get to the same answer and forget. Do we need our own error
> message
> > > > for
> > > > > > > petsc-dev?
> > > > > > >
> > > > > > > We cannot possibly guess everything that can go wrong. What we
> need
> > > > is a
> > > > > > > system
> > > > > > > where the user can specify what he actually wants and we check
> it.
> > > > So,
> > > > > > zlib
> > > > > > > and
> > > > > > > everything else are optional dependencies for hdf5. If
> something is
> > > > not
> > > > > > > specified, it
> > > > > > > fails, and the user goes back and specifies the right thing.
> > > > > >
> > > > > > Sure - but specify how? specify everything with
> > > > > > --with-hdf5-lib,--with-hdf5-include options?
> > > > > >
> > > > > > Or somehow he knows that he has to specify
> > > > > > --with-zlib-include/-with-zlib-lib options?
> > > > > >
> > > > >
> > > > > This. It would be nice if HDF5 would tell us about its
> dependencies, but
> > > > if
> > > > > it does not, then
> > > > > the user has to, and this is our system (packages).
> > > >
> > > > So we would start adding zlib.py, szip.py and manymore [and support
> > > > --download-zlib --download-szip]. And if user gets the error:
> > > >
> > > > --with-hdf5-dir=/foo/bar does not work.
> > > >
> > > > So he/she send us configure.log
> > > >
> > > > Then we look at it and respond saying: you need to specify
> --with-zlib-dir
> > > > --with-szip-dir options aswell.
> > > >
> > > > Does this look right?
> > >
> > >
> > > Yes, that is what I think makes sense.
> > >
> > > We can always try to add another layer that 'greps' for libz in the
> hdf5
> > > error message and guesses that
> > > the user forgot it, but hopefully before we get to it, a sane storage
> > > library appears, or HDF5 gets its act
> > > together.
> >
> > In this case - why bother with libz.py and szip.py? Why not tell the
> > user to specify hdf5 completely with --with-hdf5-include and
> > --with-hdf5-lib options?
> >
> > Just printing the link errors on the screen might be sufficient to
> > clue in the user. Currently its hidden inside configure. [And its not
> > clear which of the 10 tests configure did for this case should be
> > printed on the screen as the appropriate message]
>
> I might have been the one that advocated self.needsCompression approach
> thats
> currently in configure.
>
> This is currently used only by hdf5.py.
>
> My current thought is to strip it out - and just add it to hdf5.py as:
>
>     self.liblist   =
> [['libhdf5.a','libhdf5_hl.a'],'['libhdf5.a','libhdf5_hl.a','libz.a'],['libhdf5.a','libhdf5_hl.a','zlib.lib']]
>
> This would be equivalent to the current functionality - and perhaps
> what was there previously - before we wanted better error messages and
> detection of zlib. Since this is not possible anyway why bother
> with the additional complexity?


What is not possible? Detecting zlib? Of course this is possible, and we do
it.

It is not possible to know without testing what crazy link line is required
by HDF5, at
least I don't know how to do that. This is no way affects the utility of
testing for zlib.

  Matt


>
> Satish
>



-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20130411/be579e6a/attachment.html>