#ifndef _IOC_NONE
# define _IOC_NONE 0U
#endif
#ifndef _IOC_WRITE
# define _IOC_WRITE 1U
#endif
#ifndef _IOC_READ
# define _IOC_READ 2U
#endif
please explain these MACROS and their Scalar values used for determining the direction
#ifndef _IOC_NONE
# define _IOC_NONE 0U
#endif
#ifndef _IOC_WRITE
# define _IOC_WRITE 1U
#endif
#ifndef _IOC_READ
# define _IOC_READ 2U
#endif
please explain these MACROS and their Scalar values used for determining the direction
