diff --git a/library/ctr_drbg.c b/library/ctr_drbg.c
index 89b4c4c..6203fce 100644
--- a/library/ctr_drbg.c
+++ b/library/ctr_drbg.c
@@ -286,7 +286,7 @@
 
     return( 0 );
 }
-    
+
 int ctr_drbg_random_with_add( void *p_rng,
                               unsigned char *output, size_t output_len,
                               const unsigned char *additional, size_t add_len )
@@ -524,6 +524,6 @@
 
     return( 0 );
 }
-#endif
+#endif /* POLARSSL_SELF_TEST */
 
-#endif
+#endif /* POLARSSL_CTR_DRBG_C */