more debugging
diff --git a/src/libthread/iorw.c b/src/libthread/iorw.c
index 2ad8087..ce86d14 100644
--- a/src/libthread/iorw.c
+++ b/src/libthread/iorw.c
@@ -123,7 +123,8 @@
 long
 iowrite(Ioproc *io, int fd, void *a, long n)
 {
-	return iocall(io, _iowrite, fd, a, n);
+	n = iocall(io, _iowrite, fd, a, n);
+	return n;
 }
 
 static long