diff --git a/newlib/libc/sys/rtems/include/sys/ioccom.h b/newlib/libc/sys/rtems/include/sys/ioccom.h
index adaa30797..7b78db8e9 100644
--- a/newlib/libc/sys/rtems/include/sys/ioccom.h
+++ b/newlib/libc/sys/rtems/include/sys/ioccom.h
@@ -84,6 +84,9 @@ typedef unsigned long ioctl_command_t;
 #define	IOCPARM_IVAL(x)	((int)(intptr_t)(void *)*(caddr_t *)(void *)(x))
 #endif
 
+#define	_IOC_INVALID	(_IOC_VOID|_IOC_INOUT)	/* Never valid cmd value,
+						   use as filler */
+
 #endif
 
 __BEGIN_DECLS