diff --git a/src/dj.c b/src/dj.c
index a36123e..7a2512e 100644
--- a/src/dj.c
+++ b/src/dj.c
@@ -96,8 +96,9 @@ static struct Io * Io_write(struct Io *io) {
 	if ((t = write(io->fd, io->buf, io->bufuse)) < 0) {
 		io->error = errno;
 		t = 0;
-	} else if (t > 0)
+	} else if (t > 0) {
 		memmove(io->buf, &(io->buf)[t], (io->bufuse -= t));
+	}
 
 	io->bytes += t;
 	io->prec  += (t > 0 && io->bufuse > 0);