| CALLBACK(9) | Kernel Developer's Manual | CALLBACK(9) | 
callback —
#include <sys/callback.h>
void
  
  callback_head_init(struct
    callback_head *ch, int
    ipl);
void
  
  callback_head_destroy(struct
    callback_head *ch);
void
  
  callback_register(struct
    callback_head *ch, struct
    callback_entry *ce, void
    *obj, int (*fn)(struct
    callback_entry *, void *, void *));
void
  
  callback_unregister(struct
    callback_head *ch, struct
    callback_entry *ce);
int
  
  callback_run_roundrobin(struct
    callback_head *ch, void
    *arg);
callback interface allows lower-level layer
  code to execute a registered function, or set of functions, from the
  higher-level layer.
Registered functions must return one of these constants:
CALLBACK_CHAIN_CONTINUECALLBACK_CHAIN_ABORTThe callback_entry structure is an entry, normally associated with the higher-level object. It contains the internal data of the callback interface.
callback_head_init(ch,
    ipl)callback_head_destroy(ch)callback_register(ch,
    ce, obj,
    fn)callback_unregister(ch,
    ce)callback_run_roundrobin(ch,
    arg)callback interface is implemented within the file
  sys/kern/subr_callback.c.
| October 28, 2009 | NetBSD 9.3 |