diff --git a/sys/include/ape/errno.h b/sys/include/ape/errno.h
index b268d96e0..6e821c28d 100644
--- a/sys/include/ape/errno.h
+++ b/sys/include/ape/errno.h
@@ -13,6 +13,7 @@ extern int errno;
 #define E2BIG	1
 #define EACCES	2
 #define	EAGAIN	3
+#define EWOULDBLOCK	3
 #define EBADF	4
 #define EBUSY	5
 #define ECHILD	6