MTS 8: LISP and SLIP in MTS
June 1976
12 This status code is used to get or set the EOF function for
a LISP file. The argument given must be an I/O destination
atom. If an end-of-file is encountered on a read operation
from the file, the EOF function will be invoked. For a
description of the form of the EOF function and the
significance of the value returned from it, see the subsec-
tion "End-of-File Processing."
The initial value of this parameter for all files is the
system function EOF.
13 This status code is used to get or set the echo characteris-
tic for a LISP file. The argument given must be an I/O
destination atom. If the parameter value is non-NIL, all
I/O to or from the file will be echoed on *MSINK*. If the
value is NIL, echoing will not occur. The global echo
switch overrides the individual file switches if the global
switch is NIL. Otherwise, the individual file switches
control echoing.
The initial value of this parameter for all files is NIL.
14 This status code is used to get or set the file prefix
character for a LISP file. The argument given must be an
I/O destination atom. The parameter must be a literal atom,
whose first character will be used as the file prefix
character for the file. The value returned will be an
integer between 0 and 255, which represents the byte value
of the prefix character.
15 This status code is used to get or set the line number for a
LISP file. The argument given must be an I/O destination
atom. The parameter value must be an integer atom which
represents the line number parameter to be used in the next
I/O operation involving the file.
16 This status code is used to get or set the modifier word for
a LISP file. The argument given must be an I/O destination
atom. The parameter value must be an integer atom which
represents the modifier word to be used in all subsequent
I/O operations involving the file (that is, until this
parameter is changed). See the section, "Files and
Devices," in MTS Volume 1, for a description of the
significance of modifier values.
The initial value of this parameter for all files is 0.
17 This status code is used to get the maximum output line
length for the MTS file or device attached to a LISP file.
The argument given must be an I/O destination atom.
18-19 (Reserved).
70 LISP

MTS 8: LISP and SLIP in MTS
June 1976
Type II STATUS Codes--System Switches and Parameters ____________________________________________________
Code Meaning ____ _______
20 Default standard input IOARG. Initially set to the dotted-
pair of the system input buffer (size 255 characters) and
SCARDS.
21 Default standard output IOARG. Initially set to the dotted-
pair of the system output buffer (size 70 characters) and
SPRINT.
22 Default error input IOARG. Used in break loops in place of
standard input IOARG. Initially set to the dotted-pair of
the system error input buffer (size 255 characters) and
GUSER.
23 System error output IOARG. Used in break loops in place of
standard output IOARG. Initially set to the dotted-pair of
the system error output buffer (size 70 characters) and
SERCOM.
Note: These initial IOARGs may be obtained by calling
STATUS. They are also the initial values of the atoms
LISPIN, LISPOUT, ERRIN, and ERROUT (for the user’s
convenience).
24 Input number base (10, 16, or 0). 0 signifies no numerics.
Initially 10.
25 Output number base (10 or 16). Initially 10.
26 Number of levels of forms to print on EVAL form traceback.
(0 = none, -1 = all). Defaults to 3.
27 Traceback argument switch. Zero specifies only function
specifications (i.e., CAR of EVAL form) are to be printed on
EVAL form traceback. Any number greater than zero specifies
both CAR and CDR of form (i.e., both function specification
and arguments) are to be printed. The switch is initially
set to 1.
28 Most recent expression which generated an error (get only).
29 Error number of most recent error (get only).
30 Terse traceback switch. Zero specifies traceback output in
terse mode should be printed (only one line is printed for
each expression.) Any number greater than zero specifies
that a full traceback should be printed. Initially 0.
31 Global switch for echoing input lines on *MSINK*. T
specifies echo, and NIL specifies no echo. Initially NIL.
LISP 71