Access array of C++ structs from Fortran? -

in c++, allocate array of s. in fortran, want access elements of array. how can this?

c++:

struct s {double a; double b;}; s *arrayofs; arrayofs = (s *)new s[123]; // allocate 

fortran 2003:

use iso_c_binding type, bind(c) :: sfortran real(c_double) :: a,b end type sfortran 

s , sfortran should interoperable, need have way access elements of array declared in c++. i'd have sc(5)%a in fortran correspond arrayofs[4].a in c++. how declare , set proper value fortran array sc have access?

you could:

1) pass c++ array fortran bind(c) procedure takes appropriate array argument.

subroutine proc(array) bind(c, name='proc')   ...   type(sfortran) :: array(*) 

with approach might want pass size of array across , make array argument explicit shape.

b) have array pointer extern "c" global on c++ side, , interoperate through fortran module variable bind(c).

module some_module   use, intrinsic :: iso_c_binding, only: c_ptr, c_f_pointer   ...   type(c_ptr), bind(c, name='arrayofs') :: array_ptr   ...   ! in procedure in module...   type(sfortran), pointer :: array(:)   call c_f_pointer(array_ptr, array, [123]) 

again might suit have size of array available separately avoid hard coding in c_f_pointer reference.

which approach best depends on requirements!