12/23/81  apl_coded_

This PL/1 subroutine has entry points that can be called as external
functions from within APL, for the purpose of manipulating Multics
segments as stream files.  Operations equivalent to the APL standard
file handling routines are provided, plus several which are meaningful
only in the sequential access stream file environment.


Syntax:  The syntax of each entry point is described below.


List of entry points in apl_coded_:
create
   Usage:  'path_name' CREATE file_number

   (like FCREATE).  Creates segment named 'path_name' and opens it
   for stream i/o.  Path_name may be relative or absolute.  File
   number is analogous to 'tie number' in APL files but the two
   systems are independent.  (That is, you may have a stream file 7
   and an APL file 7 tied concurrently. )
eof
   Usage:  R <- EOF file_number_vector

   Returns boolean vector of 'end-of-file' status for each file
   specified.  EOF becomes true when the last character in a file has
   been read. 


nums
   Usage:  R <- NUMS

   (like FNUMS).  Returns vector of tied file numbers. 
position
   Usage:  type [,skip] POSITION file_number

    Repositions the file.  If 'type' is -1, the file is rewound.  If
    type is 0, 'skip' lines are skipped.  If 'type' is 1, the file is
    positioned after the last line.  If 'type' is 2, the file is
    positioned at the 'skip'th character.  If 'type' is 3, 'skip'
    characters are skipped.  'skip' is ignored if 'type' is -1 or 1.
    'skip' may be negative if 'type' is 0 or 3, in which case a
    backward skip is performed.  If 'skip' is omitted, 1 is assumed.


read
   Usage:  R <- no_of_lines READ file_number

    Returns character matrix of dimension [I J] where I is the number
    of lines actually read (I<=left argument) and J is the length of
    the longest line (J<=512).  Lines containing less than J characters
    are right-padded with blanks.
rewind
   Usage:  REWIND file_number_vector

    Positions each file specified in right argument so that next READ
    operation would read first line in file or next WRITE operation
    would truncate and replace file contents with the new data.


tie
   Usage:  'path_name' TIE file_number

   (like FTIE).  Opens segment named 'path_name' and opens it for
   stream i/o.  Path_name may be relative or absolute. 
untie
   Usage:  UNTIE file_number_vector

   (like FUNTIE).  Detaches each file in right argument. 
write
   Usage:  'char_vector' WRITE file_number

   Writes the characters of the left argument to the designated
   stream file.  Newline characters (octal escape "012) must be
   included explicitly if desired. 


Access:  To access the coded file functions, you must enter the
following external function definitions:

)DFN CREATE APL_CODED_$CREATE
)MFN EOF APL_CODED_$EOF
)ZFN NUMS APL_CODED_$NUMS
)DFN POSITION APL_CODED_$POSITION
)DFN READ APL_CODED_$READ
)MFN REWIND APL_CODED_$REWIND
)DFN TIE APL_CODED_$TIE
)MFN UNTIE APL_CODED_$UNTIE
)DFN WRITE APL_CODED_$WRITE


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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