Fotran pointers traveling through C++ code

Dear all,

I read a lot of tutorials about calling Fortran functions from C++ code, and I was wondering if it was possible to call a Fortran function from C++ code with pointers arguments that come from Fortran without declaring the pointed type in C++.

Let me explain: I created a derived type in Fortran, which contains a lot of derived types. I would like to be able to insert a layer of C++ between a call from one Fortran subroutine to another, and I would like to avoid to redefine the Fortran derived types in C++, something like:

module my_module
  implicit none

	 

	  type :: my_type

	    real :: x

	  end type my_type

	 

	end module my_module
subroutine fortran_subroutine(b)
  use my_module

	  implicit none
  type(my_type), pointer, intent(in) :: b
  print *, b%x
end subroutine fortran_subroutine
program test

	 

	  use my_module

	  implicit none
  abstract interface

	      subroutine sub (b)

	        import :: my_type

	        type(my_type), pointer, intent(in) :: b

	      end subroutine sub

	  end interface
  type(my_type), pointer :: a
  procedure (sub), pointer :: f_ptr => null ()

	  procedure (sub) :: fortran_subroutine
  allocate(a)

	  a%x = 1.0
  f_ptr => fortran_subroutine

	  call c_plus_plus_layer(f_ptr,a)
end program

extern "C"

	{

	  void c_plus_plus_layer_(void (*pointer_to_fortran_function)(void **), void ** x);

	}
// Intermediate layer of C++ designed to launch a Fortran subroutine

	// which doesn't have any argument

	void c_plus_plus_layer_(void (*pointer_to_fortran_function)(void **), void ** x)

	{

	  pointer_to_fortran_function(x);

	}

Thank you for your help !