06/04/82	program_interrupt, pi

Syntax:  pi


Function: informs a suspended invocation of a subsystem that the user
wishes to abort the current request.


Notes: The program interrupt command is used with interactive
subsystems.  Interactive subsystems are commands that accept user
requests from the terminal.  To abort a subsystem request the user
uses the quit (or break) key to interrupt execution, and then gives
the program_interrupt command.  If the subsystem supports the use of
the program_interrupt command, it will abort the interrupted request
and ask the user for a new one.  If the subsystem does not support the
use of program_interrupt, the command will print an error message.
The user may then either restart the interrupted operation with the
"start" command, or abort the entire subsystem invocation with the
"release" command.


List of subsystems that support pi:
   The following subsystems support the use of the 
   program_interrupt command--
debug		probe
edm		qedx
emacs		read_mail
forum		send_mail
help		teco
lisp		ted
print_mail


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Historical Background

This edition of the Multics software materials and documentation is provided and donated
to Massachusetts Institute of Technology by Group BULL including BULL HN Information Systems Inc. 
as a contribution to computer science knowledge.  
This donation is made also to give evidence of the common contributions of Massachusetts Institute of Technology,
Bell Laboratories, General Electric, Honeywell Information Systems Inc., Honeywell BULL Inc., Groupe BULL
and BULL HN Information Systems Inc. to the development of this operating system. 
Multics development was initiated by Massachusetts Institute of Technology Project MAC (1963-1970),
renamed the MIT Laboratory for Computer Science and Artificial Intelligence in the mid 1970s, under the leadership
of Professor Fernando Jose Corbato. Users consider that Multics provided the best software architecture 
for managing computer hardware properly and for executing programs. Many subsequent operating systems 
incorporated Multics principles.
Multics was distributed in 1975 to 2000 by Group Bull in Europe , and in the U.S. by Bull HN Information Systems Inc., 
as successor in interest by change in name only to Honeywell Bull Inc. and Honeywell Information Systems Inc. .

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Permission to use, copy, modify, and distribute these programs and their documentation for any purpose and without
fee is hereby granted,provided that the below copyright notice and historical background appear in all copies
and that both the copyright notice and historical background and this permission notice appear in supporting
documentation, and that the names of MIT, HIS, BULL or BULL HN not be used in advertising or publicity pertaining
to distribution of the programs without specific prior written permission.
    Copyright 1972 by Massachusetts Institute of Technology and Honeywell Information Systems Inc.
    Copyright 2006 by BULL HN Information Systems Inc.
    Copyright 2006 by Bull SAS
    All Rights Reserved