ioctl-number.rst

    ====== == ============================================
    _IO    an ioctl with no parameters
    _IOW   an ioctl with write parameters (copy_from_user)
    _IOR   an ioctl with read parameters  (copy_to_user)
    _IOWR  an ioctl with both write and read parameters.
    ====== == ============================================

Dataview (inline field '===== == ============================================
    _IO    an ioctl with no parameters
    _IOW   an ioctl with write parameters (copy_from_user)
    _IOR   an ioctl with read parameters  (copy_to_user)
    _IOWR  an ioctl with both write and read parameters.
    ====== == ============================================'): Error: 
-- PARSING FAILED --------------------------------------------------

> 1 | ===== == ============================================
    | ^
  2 |     _IO    an ioctl with no parameters
  3 |     _IOW   an ioctl with write parameters (copy_from_user)

Expected one of the following: 

'(', 'null', boolean, date, duration, file link, list ('[1, 2, 3]'), negated field, number, object ('{ a: 1, b: 2 }'), string, variable

/*
 * Used to create numbers.
 *
 * NOTE: _IOW means userland is writing and kernel is reading. _IOR
 * means userland is reading and kernel is writing.
 */
#define _IO(type,nr)		_IOC(_IOC_NONE,(type),(nr),0)
#define _IOR(type,nr,size)	_IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))
#define _IOW(type,nr,size)	_IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
#define _IOWR(type,nr,size)	_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
#define _IOR_BAD(type,nr,size)	_IOC(_IOC_READ,(type),(nr),sizeof(size))
#define _IOW_BAD(type,nr,size)	_IOC(_IOC_WRITE,(type),(nr),sizeof(size))
#define _IOWR_BAD(type,nr,size)	_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))