/usr/share/calc/help/stoponerror is in apcalc-common 2.12.4.4-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 | NAME
    stoponerror - controls when / if calc stops calculations based on errors
SYNOPSIS
    stoponerror([n])
TYPES
    n		integer
    return	null value or error value
DESCRIPTION
    The stoponerror controls when or if calc stops based on the
    number of errors:
    	n == -1		do not stop
	n == 0		stop on error unless calc was invoked with -c
	n > 0		stop when n errors are encountered
    When no arguments are given, stoponerror() returns the current
    stoponerror value.  When 1 argument is given, stoponerror() returns
    the previous stoponerror value.
EXAMPLE
    ; stoponerror()
	0
LIMITS
    -1 <= stoponerror < 2147483647
LINK LIBRARY
    none
SEE ALSO
    errcount, errmax, errorcodes, iserror, errno, strerror, newerror
## Copyright (C) 2006  Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
## distributed with calc under the filename COPYING-LGPL.  You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA.
##
## @(#) $Revision: 30.1 $
## @(#) $Id: stoponerror,v 30.1 2007/03/16 11:10:42 chongo Exp $
## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/stoponerror,v $
##
## Under source code control:	2006/05/21 00:50:59
## File existed as early as:	2006
##
## chongo <was here> /\oo/\	http://www.isthe.com/chongo/
## Share and enjoy!  :-)	http://www.isthe.com/chongo/tech/comp/calc/
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