taglinefilesource code
_IOWR49include/asm-alpha/ioctl.h#define _IOWR(type,nr,size)  _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
_IOWR50include/asm-i386/ioctl.h#define _IOWR(c,d,t)  (IOC_INOUT | ((sizeof(t)<<16) & IOCSIZE_MASK) | \
_IOWR106include/linux/soundcard.h#define  _IOWR(x,y,t)  ((int)(IOC_INOUT|((sizeof(t)&IOCPARM_MASK)<<16)|(x<<8)|y))