diff --git a/fortran_examples/test_n2.F90 b/fortran_examples/test_n2.F90
index 322bc742ed00110c15579270d74854ae350e9e99..1baadcc234583f6bcc3302459a181e722a3bd336 100644
--- a/fortran_examples/test_n2.F90
+++ b/fortran_examples/test_n2.F90
@@ -38,8 +38,8 @@ Type(Cell), Dimension(:), Allocatable :: cells
 
 Contains
 
-Subroutine Interact_single(cell_i)
-Integer, Intent(in) :: cell_i
+Subroutine Interact_single(cell_i) BIND(C)
+Integer(Kind=C_INT), Intent(in) :: cell_i
 
 Integer :: i,j
 
@@ -85,9 +85,9 @@ end do
 
 End Subroutine
 
-Subroutine Interact(cell_i, cell_j)
+Subroutine Interact(cell_i, cell_j) BIND(C)
 
-Integer, Intent(in) :: cell_i, cell_j
+Integer(Kind=C_INT), Intent(in) :: cell_i, cell_j
 
 Integer :: i, j
 Real(Kind=dp) :: xx, yy, zz, r, f, ir, ir6, ir12, fxx, fyy, fzz, fix, fiy, fiz
@@ -209,6 +209,8 @@ do i = 1, 100
   call cell_init(i, 500)
 end do
 
+print *, "num_threads = ", num_threads
+
 sched = f_qsched_create()
 call qsched_init(sched, num_threads, 0)