module f_mod
  use, intrinsic :: iso_c_binding, only : c_int, c_double, c_ptr, c_loc
  implicit none

contains
  subroutine f_func(data)
    type, bind(C) :: c_matrix
       integer(c_int) :: m
       integer(c_int) :: n
       type(c_ptr) :: data
    end type c_matrix

    interface
       subroutine c_function(mat, d) BIND(C, name='c_function')
         import c_matrix, c_double
         type(c_matrix) :: mat
         real(c_double), value :: d
       end subroutine c_function
    end interface

    type(c_matrix) :: mat
    double precision, dimension(:, :), allocatable, intent(in) :: data
    real(c_double) :: d = 1.45

    mat%m = size(data, 1)
    mat%n = size(data, 2)
    mat%data = c_loc(data(lbound(data,1), lbound(data, 2)))

    call c_function(mat, d)
  end subroutine f_func
end module f_mod