compiling a mixed GNU Fortran/C++ MPI shared library

Question

I'm trying to compile a C++ MPI wrapper to MPI Fortran library, but i fail on linking. The wrapper is compiled using

mpic++ -c my_wrapper.cc -o my_wrapper.o 

my_wrapper.cc reads:

#include "mpi.h"

extern"C" {
  void fortran_func_(int * comm,bool *do_init);
}

void c_func(MPI_Comm my_comm ) 
{
   MPI_Fint    fcomm;
   fcomm = MPI_Comm_c2f(my_comm);
   bool do_init = false;
   fortran_func_(&fcomm, &do_init);
}

The library is compiled using

  MPI_LINK_FLAGS = $(shell mpic++ --showme:link)
  mpif90 -shared my_wrapper.o $(FORTRAN-LIBS) $(MPI_LINK_FLAGS) -o my_libc++.a

here are the linking errors:

  "std::ios_base::Init::Init()", referenced from:
      __static_initialization_and_destruction_0(int, int) in my_wrapper.o
  "std::ios_base::Init::~Init()", referenced from:
      __static_initialization_and_destruction_0(int, int) in my_wrapper.o
  "vtable for __cxxabiv1::__class_type_info", referenced from:
      typeinfo for MPI::Info in my_wrapper.o
      typeinfo for MPI::Errhandler in my_wrapper.o
      typeinfo for MPI::Win in my_wrapper.o
      typeinfo for MPI::Comm_Null in my_wrapper.o
      typeinfo for MPI::Group in my_wrapper.o
      typeinfo for MPI::Request in my_wrapper.o
      typeinfo for MPI::Status in my_wrapper.o
      ...
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
  "vtable for __cxxabiv1::__si_class_type_info", referenced from:
      typeinfo for MPI::Intercomm in my_wrapper.o
      typeinfo for MPI::Graphcomm in my_wrapper.o
      typeinfo for MPI::Cartcomm in my_wrapper.o
      typeinfo for MPI::Intracomm in my_wrapper.o
      typeinfo for MPI::Comm in my_wrapper.o
      typeinfo for MPI::Grequest in my_wrapper.o
      typeinfo for MPI::Prequest in my_wrapper.o
      ...
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
  "operator delete[](void*)", referenced from:
      MPI::Datatype::Get_contents(int, int, int, int*, long*, MPI::Datatype*) const in my_wrapper.o
      MPI::Comm::Alltoallw(void const*, int const*, int const*, MPI::Datatype const*, void*, int const*, int const*, MPI::Datatype const*) const in my_wrapper.o
      MPI::Intracomm::Create_cart(int, int const*, bool const*, bool) const in my_wrapper.o
      MPI::Intracomm::Spawn_multiple(int, char const**, char const***, int const*, MPI::Info const*, int) in my_wrapper.o
      MPI::Intracomm::Spawn_multiple(int, char const**, char const***, int const*, MPI::Info const*, int, int*) in my_wrapper.o
      MPI::Cartcomm::Get_topo(int, int*, bool*, int*) const in my_wrapper.o
      MPI::Cartcomm::Sub(bool const*) const in my_wrapper.o
      ...
  "operator delete(void*)", referenced from:
      MPI::Datatype::~Datatype() in my_wrapper.o
      MPI::Datatype::~Datatype() in my_wrapper.o
      MPI::Status::~Status() in my_wrapper.o
      MPI::Status::~Status() in my_wrapper.o
      MPI::Request::~Request() in my_wrapper.o
      MPI::Request::~Request() in my_wrapper.o
      MPI::Request::~Request() in my_wrapper.o
      ...
  "operator new[](unsigned long)", referenced from:
      MPI::Datatype::Get_contents(int, int, int, int*, long*, MPI::Datatype*) const in my_wrapper.o
      MPI::Comm::Alltoallw(void const*, int const*, int const*, MPI::Datatype const*, void*, int const*, int const*, MPI::Datatype const*) const in my_wrapper.o
      MPI::Intracomm::Create_cart(int, int const*, bool const*, bool) const in my_wrapper.o
      MPI::Intracomm::convert_info_to_mpi_info(int, MPI::Info const*) in my_wrapper.o
      MPI::Cartcomm::Get_topo(int, int*, bool*, int*) const in my_wrapper.o
      MPI::Cartcomm::Sub(bool const*) const in my_wrapper.o
      MPI::Cartcomm::Map(int, int const*, bool const*) const in my_wrapper.o
      ...
  "operator new(unsigned long)", referenced from:
      MPI::Intracomm::Clone() const in my_wrapper.o
      MPI::Cartcomm::Clone() const in my_wrapper.o
      MPI::Graphcomm::Clone() const in my_wrapper.o
      MPI::Intercomm::Clone() const in my_wrapper.o
  "___cxa_pure_virtual", referenced from:
      vtable for MPI::Comm in my_wrapper.o
  "___gxx_personality_v0", referenced from:
      Dwarf Exception Unwind Info (__eh_frame) in my_wrapper.o
  ld: symbol(s) not found for architecture x86_64
  collect2: error: ld returned 1 exit status

I could not find any example how to do such things (mixed Fortran/C++ with MPI) so I ask here in a hope that it will be useful for somebody else at some point.

P.S.

If i try to compile it with mpic++ :

MPIF_LINK_FLAGS = $(shell mpif90 --showme:link)
mpic++ -shared my_wrapper.o $(FORTRAN-LIBS) $(MPIF_LINK_FLAGS) -o $@

I miss a lot of symbols from $(FORTRAN-LIBS) which i don't when i link with mpif90. So i guess i better add those missing libraries to Fortran linker.

I use Open MPI: 1.6 if it matters.

EDIT1: by adding those to mpif90 linking everything compiles:

-L/opt/local/lib/gcc47/ -lstdc++

Indeed, some standard C++ stuff was missing

Answer 1

It seems you are linking using the FORTRAN linker. It knows nothing about the C++ standard library, so all of the C++ standard library (such parts of std::ios_base) will be "undefined symbols". You need to alter your link command, to add the C++ standard library.

As your composite is neither entirely FORTRAN nor entirely C++, neither the FORTRAN nor the C++ linker are entirely appropriate. You might want to consider using ld directly. In that case, you would have to list the C++ standard library and the FORTRAN standard library as libraries to link with.