Index: uspace/lib/c/include/io/chardev_srv.h
===================================================================
--- uspace/lib/c/include/io/chardev_srv.h	(revision 5d50c419de1e8d7b6b57065ea652ba23b83e5a97)
+++ uspace/lib/c/include/io/chardev_srv.h	(revision b2f542a7efa3ca69bfbe7544962e906503d25b89)
@@ -59,6 +59,6 @@
 	int (*open)(chardev_srvs_t *, chardev_srv_t *);
 	int (*close)(chardev_srv_t *);
-	int (*read)(chardev_srv_t *, void *, size_t);
-	int (*write)(chardev_srv_t *, const void *, size_t);
+	int (*read)(chardev_srv_t *, void *, size_t, size_t *);
+	int (*write)(chardev_srv_t *, const void *, size_t, size_t *);
 };