| SHUTDOWNHOOK_ESTABLISH(9) | Kernel Developer's Manual | SHUTDOWNHOOK_ESTABLISH(9) | 
shutdownhook_establish,
  shutdownhook_disestablish —
shutdownhook_establish(void
  (*fn)(void *), void
  *arg);
void
  
  shutdownhook_disestablish(void
    *cookie);
shutdownhook_establish
  API is deprecated.
The shutdownhook_establish() function adds
    fn to the list of hooks invoked by
    doshutdownhooks(9) at
    shutdown. When invoked, the hook function fn will be
    passed arg as its only argument.
The shutdownhook_disestablish() function
    removes the hook described by the opaque pointer
    cookie from the list of hooks to be invoked at
    shutdown. If cookie is invalid, the result of
    shutdownhook_disestablish() is undefined.
Shutdown hooks should be used to perform one-time activities that must happen immediately before the kernel exits. Because of the environment in which they are run, shutdown hooks cannot rely on many system services (including file systems, and timeouts and other interrupt-driven services), or even basic system integrity (because the system could be rebooting after a crash).
shutdownhook_establish() returns an
  opaque pointer describing the newly-established shutdown hook. Otherwise, it
  returns NULL.
It may be appropriate to use a shutdown hook to inform watchdog timer hardware that the operating system is no longer running.
| May 14, 2009 | NetBSD 9.3 |