tag	line	file	source code
IOC_VOID	39	include/linux/ioctl.h	#define _IO(c,d)  (IOC_VOID | ((c)<<8) | (d)) /* param encoded */
IOC_VOID	82	include/linux/soundcard.h	#define  _IO(x,y)  ((int)(IOC_VOID|(x<<8)|y))