diff --git a/src/templates_front/templator_front.org b/src/templates_front/templator_front.org
index 0ab443b..ba936ed 100644
--- a/src/templates_front/templator_front.org
+++ b/src/templates_front/templator_front.org
@@ -604,7 +604,7 @@ interface
    logical(c_bool) function trexio_has_back_end (back_end) bind(C)
      use, intrinsic :: iso_c_binding
      import
-     integer(c_int32_t), intent(in), value :: back_end
+     integer(trexio_back_end_t), intent(in), value :: back_end
    end function trexio_has_back_end
 end interface
 
@@ -612,7 +612,7 @@ interface
    logical(c_bool) function trexio_has_backend (back_end) bind(C)
      use, intrinsic :: iso_c_binding
      import
-     integer(c_int32_t), intent(in), value :: back_end
+     integer(trexio_back_end_t), intent(in), value :: back_end
    end function trexio_has_backend
 end interface
   #+end_src
@@ -984,7 +984,7 @@ trexio_open(const char* file_name, const char mode,
 
    #+begin_src f90 :tangle prefix_fortran.f90
 interface
-   integer(c_int64_t) function trexio_open_c (filename, mode, back_end, rc_open) bind(C, name="trexio_open")
+   integer(trexio_t) function trexio_open_c (filename, mode, back_end, rc_open) bind(C, name="trexio_open")
      use, intrinsic :: iso_c_binding
      import
      character(kind=c_char), dimension(*)          :: filename