dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Thu, Jun 04, 2009 at 06:10:29PM +0200, Martin Sandve Alnæs wrote:
> On Thu, Jun 4, 2009 at 5:52 PM, Anders Logg <logg@xxxxxxxxx> wrote:
> > On Thu, Jun 04, 2009 at 12:37:57PM +0200, Johan Hake wrote:
> >> On Thursday 04 June 2009 12:23:59 Harish Narayanan wrote:
> >> > Martin Sandve Alnæs wrote:
> >> > > On Thu, Jun 4, 2009 at 11:14 AM, Johan Hake <hake@xxxxxxxxx> wrote:
> >> > >> On Thursday 04 June 2009 10:59:39 Johannes Ring wrote:
> >> > >>> On Thu, June 4, 2009 10:46, Johan Hake wrote:
> >> > >>>> [snip]
> >> > >>>>
> >> > >>>>> I don't have a problem with pkg-config being _the_ system,
> >> > >>>>> but the command line interface does not give that impression.
> >> > >>>>> It cannot be required that the user knows scons internals or takes
> >> > >>>>> even a casual glance at the implementation of the build system...
> >> > >>>>
> >> > >>>> True.
> >> > >>>>
> >> > >>>>> In particular, there is no mention of pkg-config in scons --help,
> >> > >>>>> README, or INSTALL, and the help messages do not suggest
> >> > >>>>> that they may be ignored if the wind comes from the north:
> >> > >>>>> withPetscDir: Specify path to PETSc ( /path/to/withPetscDir )
> >> > >>>>
> >> > >>>> Also true.
> >> > >>>>
> >> > >>>>> If scons makes it hard to design the interface freely, why not
> >> > >>>>> have a separate script to generate selected pkg-config files?
> >> > >>>>> I don't care more for "scons configFoo" than
> >> > >>>>> "configure withFooDir=/here/I/am withBarDir=/here/I/am".
> >> > >>>>>
> >> > >>>>> Whatever solution is chosen, it must be possible to say
> >> > >>>>> explicitly that "hey, I want to use foolib from /bar/foolibdir,
> >> > >>>>> please make me a pkg-config file for that build and ignore
> >> > >>>>> any global defaults that you find".
> >> > >>>>
> >> > >>>> Ok, I can discuss it with Johannes and see if there are any good
> >> > >>>> solution for
> >> > >>>> this.
> >> > >>>>
> >> > >>>> Suggestion 1:
> >> > >>>> Trigger construction of a specific pkg-config file during compilation.
> >> > >>>>
> >> > >>>>   scons configFoo configBar
> >> > >>>>
> >> > >>>> These options will come in addition to other options. Maybe more
> >> > >>>> explicit towards mentioning pkg-config
> >> > >>>>
> >> > >>>>   scons generatePkgConfigFoo generatePkgConfigBar?
> >> > >>>>
> >> > >>>> Suggestion 2:
> >> > >>>> Put the generation of pkg-config files into a standalone script.
> >> > >>>>
> >> > >>>>   generate-pkg-config Foo Bar
> >> > >>>>
> >> > >>>> Instead of generate-pkg-config-file we could for example have:
> >> > >>>>
> >> > >>>>   dolfin-config, config?
> >> > >>>>
> >> > >>>> I think 1 integrates better with the present system.
> >> > >>>>
> >> > >>>> Any comments from the others?
> >> > >>>
> >> > >>> I like better suggestion 1, however, it should be possible to generate
> >> > >>> new pkg-config files whenever withFooDir=/path/to/foo is specified on
> >> > >>> the command line. Isn't that better?
> >> > >>
> >> > >> Maybee, less options is good. However as it is now this will then be
> >> > >> cached, and scons will trigger the build each time.
> >> > >>
> >> > >> A solution that might work is to make that option uncachable. So
> >> > >> whenever withFooDir=/path/to/foo is explicitly used we try to generate a
> >> > >> pkg-config file. Anyhow that option is only used once, for building
> >> > >> Foo's pkg-config file (if not any others are found on the system :) ) so
> >> > >> making it an uncached option would make sense.
> >> > >>
> >> > >> However it is not very logical that the construction of a pkg-config
> >> > >> file should be triggered when a directory is passed.
> >> > >>
> >> > >> Johan
> >> > >
> >> > > A related issue: it is very common to run "scons <options>", look at the
> >> > > output, and abort the build with ctrl+c if some library isn't found. It
> >> > > would be nice if we had a configuration step that didn't start the build.
> >> > > This step should probably be the same as what's discussed above?
> >> >
> >> > And the opposite would be nice too. i.e. To be able to do scons
> >> > <something> and not need to configure.
> >> >
> >> > e.g. I was having some trouble with boost and so I removed it. I then
> >> > tried to unmake and uninstall dolfin by scons -c and scons -c install,
> >> > and they both fail because of a lack of boost (which gets flagged on an
> >> > unnecessary configure).
> >>
> >> Splitting the build and configure part is kind of logical. I think the simula
> >> scons was built to remove the distintion between these two ;) However the
> >> complexity of dolfin starts to require more composite logics.
> >>
> >> So, based on the options passed to the configuration step, enableFoo
> >> withFooDir aso, we check whats available, create pkg-config files store them
> >> locally. Give the user information about the result of the config step.
> >>
> >> The build step will then just build (or clean) what ever specified in some
> >> cached option file, which is generated by the configure step.
> >>
> >> Any locally stored pkg-config files produced from the configure step will be
> >> installed during an installation step.
> >>
> >> This should be possible with some refactoring of the code, but I think we need
> >> some consensus about it. simula scons is also used by other packages too.
> >
> > I agree. We need configure + build:
> >
> > 1. The configure step checks for required packages, using pkg-config.
> >
> > 2. If a required package is not found,
> 
> OR if a specific version is requested on the commandline,

Yes.

-- 
Anders


> > it tries to generate the
> > pkg-config file.
> 
> 
> > 3. The build step just builds, using pkg-config to get libraries.
> >
> > This way, caching is the same as stored configuration so there should
> > be little confusion about caching.
> 
> Martin
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