[petsc-dev] need c++ expert help

[Matthew Knepley]

On Sun, Dec 31, 2017 at 2:35 PM, Jed Brown <jed at jedbrown.org> wrote:

> Matthew Knepley <knepley at gmail.com> writes:
>
> > On Sun, Dec 31, 2017 at 1:55 PM, Jed Brown <jed at jedbrown.org> wrote:
> >
> >> These look like linker errors and that build uses
> >> --with-cxxlib-autodetect=0.  We either need a rule to *link* C++ using
> >> CXX (i.e., mpicxx) or add LIBS=-lstdc++.
> >>
> >
> > I thought we were doing this (linking C++ mains with CXX).
>
> After compiling to the object file (ex3.o) we don't know what language
> main was written in, and this doesn't solve the actual problem that C++
> linking is required if any object (not just main) depends on C++.
>

My thinking here was the following:

  1) No C++ is allowed in PETSc, unless --with-clanguage=cxx, in which case
the linker is C++
  2) If C++ is in an external library, then that configure requires the C++
library
  3) The executable itself could be C++, in which case I proposed using the
C++ linker explicitly

About not knowing which objects come with C++ main: I thought we did. Don't
they go into a separate set?

  Matt

-- 
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

https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20171231/2892d129/attachment.html>