Symbol: IOC_VOID
sys/kern/sys_generic.c
488
else if (com&IOC_VOID)
sys/sys/ioccom.h
62
#define _IO(g,n) _IOC(IOC_VOID, (g), (n), 0)
usr.bin/kdump/kdump.c
1549
if ((cmd & IOC_VOID) == 0)