$f10=63 s=1.8
$f11=63 s=1.5
$f14=14 s=1.2
$f15=16 s=1.0 h=0.17"
$f16=16 s=1.15 h=0.22"
$16
$d %=$w$u
$a left=12; line=-12; page=+3
$l1mbu
IMP EVENT NUMBERING
$15
$l
$c70 Proposed revision -- HD 10/04/84
$d |=$t+
$a tab=12,22,40
$l0$i

$c-2 %$hevent |$c-2%$hsub |$c-2 %$hextra |%$hmeaning

0|||$c-4 $H(PROGRAM TERMINATION)
|0|-|normal termination (%stop)
|n|-|abnormal termination

1|||$c-4 $H(OVERFLOW)
|1|-|integer overflow
|2|-|real overflow
|3|-|string overflow (more than 255 characters)
|4|-|division by zero

2|||$c-4 $H(RESOURCE EXCEEDED)
|1|-|store space exhausted
|2|-|output limit exceeded
|3|-|time limit exceeded

3|||$c-4 $H(INPUT/OUTPUT ERROR)
|1|-|data transmission error
|2|-|timeout
|3|code|failure to open file
|4|code|failure on other file system operation

4|||$c-4 $H(INPUT DATA TYPE ERROR)
|1|char|non-numeric char for numeric input

5|||$c-4 $H(INVALID ARGUMENTS)
|1|-|invalid values for %for loop
|2|culprit|illegal exponent for exponentiation
|3|-|upper bound less than lower in array declaration

6|||$c-4 $H(RANGE ERROR)
|1|value|value outside range of destination/result
|2|index|array index out of bounds
|3|index|switch index out of bounds (if distinguished from 2)

7|||$c-4 $H(STRING RESOLUTION FAILURE)

8|||$c-4 $H(UNDEFINED VALUE)
|1|-|unassigned variable
|2|index|switch to undefined label
|3|-|%for loop variable corrupt

9|||$c-4 $H(END OF INPUT)

10|||$c-4 $H(LIBRARY PROCEDURE ERROR)

11-15|||$c-4 $H(GENERAL PURPOSE)

$b
In general, reliance should not be placed on the detailed distinctions made by
the EVENT$0(_)SUB field: the EVENT$0(_)MESSAGE field provides a textual
explanation for the occurrence of the event.
$b
The reversal of the significance of events 3 and 4 compared with EMAS IMP
was unintended in IMP-77. The re-reversal shown above corrects this in
the interests of goodwill.