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 9.2 |