Topic       : TOS - The Operating System
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View Ref-File11.5.9.2  Shutdown in MagiC                                        TOS

Under MagiC the Shutdown works a follows: all running programs receive 
an AP_TERM message signalling that they should terminate themselves. 
If there are still programs in memory after a certain time, then 
SHUTDOWN outputs an error-message. In the file SHUTDOWN.INF one can 
specify program names (without a suffix such as '.prg' or '.app') that 
are uncritical and should not lead to an error-message from SHUTDOWN.

In addition to this the following points have to be heeded:

   . If [Control]-[Alternate]-[Delete] is to be used to terminate the 
     system, one must ensure that the screen is not locked, i.e. that 
     a program is not currently processing a dialog box or alert on 
     the screen, for instance. Furthermore a suitable shell (such as 
     MAGXDESK, Thing or Jinnee) must have been loaded, i.e. no program 
     may be loaded in 'single-mode' or in the 'Shell not resident' 
     mode (say with [Alternate]-double-click).

   . f the screen is locked, then only the writeback-demon will be 
     terminated, i.e. the cache written back. Only after the screen is 
     released (i.e. after closing of the dialog or alert box) can the 
     Shutdown be performed.

   . Should the system have crashed in such a way that no Shutdown is 
     possible any more, then [Control]-[Alternate]-[Delete] should be 
     performed for a second time; a warm start will be carried out 
     without programs being terminated

   . If 'single-mode' is active or the shell is not loaded, then again 
     only the writeback-demon will be terminated and the cache written 
     back. For a complete Shutdown the running program has to be 
     terminated so that the shell is active again. The Shutdown then 
     must be performed via the 'File/Shutdown' menu entry.

In MagiC 4, the Shutdown mechanism was revised as follow: The AES now 
sends a SHUT_COMPLETED message with buf[3] = 0 (i.e. 'Shutdown 
terminated unsuccessfully') and buf[4] = -1 (invalid ap_id) if there 
are still programs running in the system that do not understand 
AP_TERM explicitly. With that, a program that only masters the 
MultiTOS specification will break off the Shutdown. SHUTDOWN.PRG, on 
the other hand, was adapted to the new specification, and functions as 
previously, i.e. gives all programs still running a timeout and then 
outputs the names of all reluctant applications.

In addition, the application #0 is no longer passed arbitrary data in 
buf[4,5,6,7] on [Control]-[Alternate]-[Delete], but the following 
message:

  buf[3]     = -1
  buf[4,6,7] =  0
  buf[5]     = AP_TERM

See also:
Shutdown in MultiTOS   shel_write   Shutdown at the receiver 
Shutdown at the initiator