diff --git a/lib/mbiter.h b/lib/mbiter.h
index b274da7..99c80e9 100644
--- a/lib/mbiter.h
+++ b/lib/mbiter.h
@@ -129,6 +129,7 @@ mbiter_multi_next (struct mbiter_multi *iter)
       iter->cur.wc = *iter->cur.ptr;
       iter->cur.wc_valid = true;
     }
+#if (HAVE_MBSINIT && HAVE_MBRTOWC)
   else
     {
       assert (mbsinit (&iter->state));
@@ -169,6 +170,7 @@ mbiter_multi_next (struct mbiter_multi *iter)
 	    iter->in_shift = false;
 	}
     }
+#endif
   iter->next_done = true;
 }
 
diff --git a/lib/mbuiter.h b/lib/mbuiter.h
index 213e710..92a5f2f 100644
--- a/lib/mbuiter.h
+++ b/lib/mbuiter.h
@@ -137,6 +137,7 @@ mbuiter_multi_next (struct mbuiter_multi *iter)
       iter->cur.wc = *iter->cur.ptr;
       iter->cur.wc_valid = true;
     }
+#if (HAVE_MBSINIT && HAVE_MBRTOWC)
   else
     {
       assert (mbsinit (&iter->state));