01/12/82  APL Search Paths

The MR9.0 release of APL offers the ability for the site and/or the
user to specify search paths to be used by the APL executive when
searching for an external function or a workspace to be loaded.  This
permits the site and/or the user to designate one or more directories
as libraries of workspaces and external functions.  If no search paths
are defined for APL, workspaces and external functions are searched
for in the same way as with previous versions of APL.

The user may determine if the site has defined search paths for APL
and, if so, what they are, by entering the command 'print_search_paths
apl'.  If the site does not define any search paths for APL, the user
may do so with the 'set_search_paths' command.  Once search paths have
been defined for APL, the user may use the 'add_search_paths' and
'delete_search_paths' commands to modify them.


Effect of search paths on the ')LOAD' command:
If the workspace in a ')LOAD' command is identified by an entry name
rather than an absolute or relative pathname, it is searched for first
in the directories specified by any APL search paths, and then in the
user's working directory.


Effects of search paths on the ')DFN', ')MFN' & ')ZFN' commands:
If the function in an external function definition command is
identified by a reference name rather than an absolute or relative
pathname, it is searched for first among the already initiated
segments, then in the directories specified by any APL search paths,
and finally according to the current search rules.


Effects of search paths on the 'qCALL' function:
'qCALL' searches for the external routine it is to invoke first among
the already initiated segments, then in the directories specified by
any APL search paths, and finally according to the current search
rules.  If any of the arguments to the external routine to be called
are themselves external routines, they are searched for in the same
way. 


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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