MTS 8: LISP and SLIP in MTS
Page Revised February 1979 June 1976
By putting an internal trace indicator on the atom T, i.e., (TRACE
T), the user can cause all trace output to be in terse mode; that is,
for each entry to or exit from a traced routine, only one line of trace
output will be printed. Removing the trace indicator from T, i.e.,
(UNTRACE T), causes tracing to revert to normal mode.
TRACE and UNTRACE are both N-type functions, and their argument-
designators are not EVALed.
| The following functions may not be traced or BUGged: LAMBDA,
NLAMBDA, FLAMBDA, LABEL, and all arrays.
Error Codes ___________
Following is a list of the errors recognized by the system. Each
type of error sets up an error message and an error expression, which
may be obtained (or altered) by calling STATUS, or which may be printed
by calling DUMP. Since the default error form for all errors is (DUMP
7), which includes a printout of the current error message and error
expression, these will normally be printed every time an error occurs.
Error types 0, 1, 3, and 4 use NIL for their error expression. Other
errors use as an error expression the argument which caused the error,
unless otherwise noted.
Code Meaning ____ _______
0 Program interrupt. Likely to be caused by a CDR operation
on a numeric atom. For this error only, an attention
interrupt which occurs during the printing of the error
message will cause an immediate return to MTS.
1 Attention interrupt.
2 Timer interrupt.
3 A function was called with too few arguments.
4 A function was called with too many arguments.
5 Numeric operation failure--numeric overflow, division by 0,
etc.
6 An array specification contained too few or too many
subscripts.
7 An atom used as a function specification had a SUBR, NSUBR,
or FSUBR property on its PLIST, but the PVAL was not a LISP
subroutine.
64 LISP

MTS 8: LISP and SLIP in MTS
June 1976 Page Revised January 1983
8 A list was required as an argument, but something else was
given.
9 An atom was required as an argument, but something else was
given.
10 A numeric atom was required as an argument, but something
else was given.
11 An integer atom was required as an argument, but something
else was given.
12 A buffer (IOARG) was required as an argument, but something
else was given.
13 A file (IOARG) was required as an argument, but something
else was given.
14 An array name was required as an argument, but something
else was given.
15 A call to the ERR function has occurred.
16 An atom is undefined or a function definition is missing.
17 Infinite EVAL loop--the function specification in process by
EVAL is an atom which has no system function definition on
its property-list, and which has itself as its VALUE.
18 Syntax error detected by READ. The error expression is the
contents of the READ buffer.
19 Attempt to OPEN a buffer with a size which is nonpositive or
greater than 255 characters.
20 Invalid request code number in a call to STATUS.
21 Invalid error number given in a STATUS code 1 call.
22 Attempt to set a "get-only" STATUS code.
23 Attempt to reset a buffer to a size less than its current
contents.
24 The number of steps specified in a STEP call have been
completed.
25 A dummy argument of a PROG or LAMBDA, or the function name
of a LABEL, was not an atom.
26 An atomic argument to GO was not the name of any current
GO-label.
LISP 65