NAME    [Toc]    [Back]

       register_callback  -  General:  Registers  a configuration
       callback routine

SYNOPSIS    [Toc]    [Back]

       int register_callback(
               void (*function) (),
               int point,
               int order,
               ulong argument );

ARGUMENTS    [Toc]    [Back]

       Specifies the name of the routine that you want called  at
       a  later  time.  Specifies the dispatch point at which the
       kernel calls this callback routine. The kernel passes  the
       value  associated  with  this dispatch point to the kernel
       module's callback routine when it calls it.  Specifies the
       order  in  which you want callback routines registered for
       the same dispatch point to be executed. The kernel  passes
       the  value  associated  with this order to the kernel module's
 callback routine when it calls  it.   You  use  this
       argument  to  control  the  order of execution of multiple
       callback routine within each dispatch  point.  The  register_callback
  routine  executes a kernel module's callback
       routine for the same dispatch point in increasing  numerical
  order  of  the value specified in the order argument.
       Specifies an argument that you want the kernel to pass  to
       the  kernel module'scallback routine when the kernel calls
       it. You pass the integer constant 0L to indicate that  you
       do not want to pass an argument.

DESCRIPTION    [Toc]    [Back]

       The  register_callback routine registers a kernel module's
       callback routine. The kernel calls a kernel module's callback
 routine when execution reaches the point specified in
       the point and order arguments. The kernel passes the  values
  specified  in the point and argument arguments to the
       kernel module's callback routine. Kernel modules implement
       one or more callback routines to handle the different dispatch
 points in the boot path.

       The dispatch point constants you can  pass  to  the  point
       argument  are  defined in the /usr/sys/include/sys/sysconfig.h
 file. The following table lists the  dispatch  point
       constants  that kernel modules can use: The dispatch point
       is hardware preconfiguration. Tasks that  do  not  require
       completion  of  hardware configuration can be performed at
       this dispatch point.  The dispatch point is hardware postconfiguration.
  Tasks  that require completion of hardware
       configuration can be performed  at  this  dispatch  point.
       The  dispatch  point  is root file system available. Tasks
       that require completion of  the  root  file  system  mount
       operation can be performed at this dispatch point.

       The order constants you can pass to the order argument are
       defined in the /usr/sys/include/sys/sysconfig.h file.  The
       following table lists the order constants that kernel modules
 can use: This callback routine is registered  at  the
       lowest  priority.   Typically, you pass this constant with
       an appropriate offset. The kernel executes  callback  routines
  registered  at  this  priority last.  This callback
       routine is registered at the highest priority.  Typically,
       you  pass  this  constant  with an appropriate offset. The
       kernel executes callback routines registered at this  priority
 first.

NOTES    [Toc]    [Back]

       The kernel maintains an internal callback list that stores
       the values you  pass  to  the  register_callback  routine.
       These  callbacks  remain registered until the user removes
       them.

       Only statically configured kernel modules need  to  implement
  callback  routines. Thus, only statically configured
       kernel modules need to call the register_callback routine.

       You  typically call the cfgmgr_get_state routine to determine
 if the kernel module is in the dynamic  configuration
       state or the static configuration state.

RETURN VALUES    [Toc]    [Back]

       Upon  successful completion, the register_callback routine
       returns the value ESUCCESS.

       Otherwise, register_callback returns one of the  following
       error  constants  defined in /usr/sys/include/sys/errno.h:
       The  system  limit  on  the  maximum  number  of  callback
       requests  was  exceeded.  To  change the maximum number of
       callback requests, set the new  value  for  the  boot-time
       tunable   parameter  max_callbacks  in  the  cm  subsystem
       (located in the /etc/sysconfigtab database) and reboot the
       system.  You can use the sysconfigdb utility to accomplish
       this task.  The value you passed to the point argument  is
       outside the minimum and maximum range.

FILES    [Toc]    [Back]

SEE ALSO
       Kernel  routines:  cfgmgr_get_state(9r),  unregister_callback(9r)



                                            register_callback(9r)