diff --git a/bufferevent_filter.c b/bufferevent_filter.c
index 6886aca0..7f19eb9a 100644
--- a/bufferevent_filter.c
+++ b/bufferevent_filter.c
@@ -428,6 +428,7 @@ be_filter_readcb(struct bufferevent *underlying, void *_me)
 
 	/* XXXX use return value */
 	res = be_filter_process_input(bevf, state, &processed_any);
+	(void)res;
 
 	/* XXX This should be in process_input, not here.  There are
 	 * other places that can call process-input, and they should
diff --git a/bufferevent_openssl.c b/bufferevent_openssl.c
index 3d9a7701..02a6222a 100644
--- a/bufferevent_openssl.c
+++ b/bufferevent_openssl.c
@@ -1013,6 +1013,7 @@ be_openssl_outbuf_cb(struct evbuffer *buf,
 		consider_writing(bev_ssl);
 	}
 	/* XXX Handle r < 0 */
+        (void)r;
 }
 
 
diff --git a/bufferevent_sock.c b/bufferevent_sock.c
index 1d76ea14..6aff91ea 100644
--- a/bufferevent_sock.c
+++ b/bufferevent_sock.c
@@ -451,6 +451,7 @@ bufferevent_connect_getaddrinfo_cb(int result, struct evutil_addrinfo *ai,
 	/* XXX use the other addrinfos? */
 	/* XXX use this return value */
 	r = bufferevent_socket_connect(bev, ai->ai_addr, (int)ai->ai_addrlen);
+	(void)r;
 	_bufferevent_decref_and_unlock(bev);
 	evutil_freeaddrinfo(ai);
 }