C++ and Fortran linking

Hello,

I'm trying to link C++ and fortran prorgam together, but I get the following error

/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/crt1.o: In function `_start':

(.text+0x20): undefined reference to `main'

The main program is fortran, calling a C routine. The linking must be done using C compiler (Because in my work I'm in fact compiling with nvcc (nvidia compiler for cuda) and the linking then can not be done using fortran compiler). I didn't find on the web anything that worked.

Moreover, GNU compiler is working fine (I pasted the test code at the end),

g++  -lstdc++ -g -c add.c
g++ -g -o main main.o add.o -lstdc++ -lgfortran

and then,

 Hola
 a+b =            3           6           9          12          15

But compilation with Intel compiler fails,

ifort -cxxlib -lstdc++ -g -c main.f90
icpc -cxxlib -lstdc++ -g -c add.c
icpc -g -o main main.o add.o -lstdc++ -lifcore
/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
Makefile:12: recipe for target 'main' failed
make: *** [main] Error 1

Does someone know what is wrong with my compilation?

Thank you,

Marc Barbry

The C code (add.c),

#include <stdlib.h>
#include <stdio.h>
#include "add.h"

extern "C" void addition_(int *a, int *b, int *c, int *Np)
{
  int N = *Np;
  int i;

  for (i=0; i<N; i++)
  {
    c[i] = a[i] + b[i];
  }

}

C header (add.h),

extern "C" void addition_(int *a, int *b, int *c, int *Np);

and Fortran code (main.f90),

program main

  implicit none
  integer, allocatable :: a(:), b(:), c(:)
  integer :: i, N

  N = 5
  print*, 'Hola'

  allocate(a(N))
  allocate(b(N))
  allocate(c(N))
  c = 0

  do i=1, N
    a(i) = i
    b(i) = 2*i
  enddo

  call addition(a, b, c, N)

  print*, "a+b = ", c

  deallocate(a)
  deallocate(b)
  deallocate(c)

end program