| NULLOP(9) | Kernel Developer's Manual | NULLOP(9) | 
nullop —
#include <sys/systm.h>
int
  
  nullop(void
    *v);
void
  
  voidop(void);
int
  
  enodev(void);
int
  
  enxio(void);
int
  
  enoioctl(void);
int
  
  enosys(void);
int
  
  eopnotsupp(void);
nullop() function provides a generic “null
  operation”. It always returns the value 0. The
  voidop() function takes no arguments and does nothing.
The enodev(),
    enxio(), enoioctl(),
    enosys(), and eopnotsupp()
    functions always fail, returning ENODEV,
    ENXIO, ENOTTY,
    ENOSYS, and EOPNOTSUPP,
    respectively.
nullop()
  may be useful:
uint64_t xc; ... xc = xc_broadcast(0, (xcfunc_t)nullop, NULL, NULL); xc_wait(xc);
| July 25, 2010 | NetBSD 9.3 |