[petsc-users] petsc cmake config - BUILD_SHARED_LIBS

[Satish Balay]

As mentioned - PETScConfig.cmake is primarily for building PETSc - and
not equivalent to .pc file

It gets used when 'make all-cmake' is used instead of the default
'make all' to build petsc libraries.

[This mode is deprecated - and not properly tested - and I see its currenty broken]

Jed had a tool FindPETSc.cmake - which is a tool for the user to
detect petsc config via cmake.

https://github.com/jedbrown/cmake-modules/

Is this what you are using?

Satish

On Tue, 13 Oct 2015, Arne Morten Kvarving wrote:

> Yes I am aware and i can reset and such.
> This is about the why, not the how. The config file has nothing to do with the petsc build system, it is for users of petsc, like a .pc file (pkgconfig).
> 
> The code in question builds a number of convenience libraries for shared code between multiple apps. I want these static at times but in general shared for installs. This I control using the intended cmake mechanism - namely the BUILD_SHARED_LIBS variable. Petsc breaks this since it overrides the value passed by the user.
> 
> I would rather avoid hacking my buildsystem to workaround petsc bugs. Right now i need to deploy a patched petsc everywhere for this reason - to remove the useless variable writing in the cmake config file. Because as you say shared libs should normally be used.
> 
> 
> -------- Opprinnelig melding --------
> Fra: Satish Balay <balay at mcs.anl.gov>
> Dato: 13.10.2015 16.56 (GMT+01:00)
> Til: Arne Morten Kvarving <Arne.Morten.Kvarving at sintef.no>
> Ko: petsc-users at mcs.anl.gov
> Emne: Re: [petsc-users] petsc cmake config - BUILD_SHARED_LIBS
> 
> Well the current code has the option of building petsc via cmake [but
> this mode is deprecated - and the default build uses straight gnumake]
> 
> So if you configure PETSc with --shared-libraries=1 [default] - this
> flag is set in conf/PETScConfig.cmake
> 
> So you can rebuild petc with --shared-libraries=0 - and this flag will
> go away.
> 
> BTW: I'm not sure why this affects your application. [as applications
> don't build libraries]. Or is it that you have a library that builds
> over PETSc?
> 
> [in this case - it generally makes sense to build it as shared anyway]
> 
> Also - I'm guessing - there must be a way for you to reset this variable in
> your cmake config - if thats whats requred by your app.
> 
> Jed should be able to confirm..
> 
> Satish
> 
> 
> On Tue, 13 Oct 2015, Arne Morten Kvarving wrote:
> 
> > hi there;
> >
> > why does the cmake config file set the BUILD_SHARED_LIBS variable? this
> > affects all buildsystem where the config file is included, and has 0 effect on
> > the actual petsc side of things.
> >
> > i don't see why petsc should decided whether i want to use static libraries in
> > my application or not.
> > i can keep hacking around it, or supply a patch to get rid of it. but i
> > figured i'd ask for the reasoning first.
> >
> > if this should have gone to -dev, i'm sorry. i thought it fit better here.
> >
> > arnem
> >
> >
> 
>