diff --git a/examples/int_div_example.c b/examples/int_div_example.c
index c0495e6cef0114b5bf04b05d07e0541a4c427c40..93d3f542c8c41e6241878d8f3b167aaaae7d7b48 100644
--- a/examples/int_div_example.c
+++ b/examples/int_div_example.c
@@ -88,6 +88,13 @@ int main(void) {
 #ifdef HAVE_GMP
   printf("  %d discrepancies reported.\n", cnt);
 #endif
+
+  /* additional calls (test interfaces). */
+  t_number p1; /* dividend */
+  convert_basis(day_fraction1 * (t_int) 20, &p1, 2, 0);
+  convert_basis(days1, &p1, W_DIGITS-3, 3);
+  print_number(p1);
+
   printf("test program done after %d tests.\n", NREPEAT);
   exit(0);
 }
diff --git a/include/int_div.h b/include/int_div.h
index b1e20dadd81dfdb65ddc7560ebb1dbe2c0711517..b3e0da41eaa7599367a624cb7ae10a4be47115f0 100644
--- a/include/int_div.h
+++ b/include/int_div.h
@@ -25,10 +25,7 @@ typedef int64_t t_int;
 typedef t_int t_number[W_DIGITS + 1];
 
 
-#ifdef DEBUG
 void         print_number(const t_number x);
-#endif
-
 void         number_init(t_number *x, const t_int val, const unsigned int m);
 unsigned int length(const t_number x);
 void         product(t_number *x, const t_number y, const t_int k, const t_int b, int* ret);
diff --git a/src/int_div.c b/src/int_div.c
index 0228ec2c50e9a0710748988594e7c31d7ba1953a..cab131d666abf0970172275e258f77b0684b29aa 100644
--- a/src/int_div.c
+++ b/src/int_div.c
@@ -240,8 +240,6 @@ int divide_timespan(const t_int days1, const t_int day_fraction1,
 }
 
 
-#ifdef DEBUG
-
 #include <stdio.h>
 #include <inttypes.h>
 
@@ -252,4 +250,4 @@ void  print_number(const t_number x) {
     printf("%" PRId64 " ", x[i]);
   printf("\n");
 }
-#endif
+