add this.
diff --git a/src/libthread/ioproc.h b/src/libthread/ioproc.h
new file mode 100644
index 0000000..f3a488d
--- /dev/null
+++ b/src/libthread/ioproc.h
@@ -0,0 +1,14 @@
+#define ioproc_arg(io, type)	(va_arg((io)->arg, type))
+
+struct Ioproc
+{
+	int tid;
+	Channel *c, *creply;
+	int inuse;
+	long (*op)(va_list*);
+	va_list arg;
+	long ret;
+	char err[ERRMAX];
+	Ioproc *next;
+};
+