#define _IOC_READ 2U
#define _IO(a,b) _IOC(_IOC_NONE,(a),(b),0)
-#define _IOW(a,b,c) _IOC(1,(a),(b),sizeof(c))
-#define _IOR(a,b,c) _IOC(2,(a),(b),sizeof(c))
-#define _IOWR(a,b,c) _IOC(3,(a),(b),sizeof(c))
+#define _IOW(a,b,c) _IOC(_IOC_WRITE,(a),(b),sizeof(c))
+#define _IOR(a,b,c) _IOC(_IOC_READ,(a),(b),sizeof(c))
+#define _IOWR(a,b,c) _IOC(_IOC_READ|_IOC_WRITE,(a),(b),sizeof(c))
#define TCGETS 0x5401
#define TCSETS 0x5402