dnl @ ../doc/m4.texi:6193: Origin of test
dnl @ expected status: 0
dnl @ extra options: 
dnl @ Copyright (C) 2006, 2007, 2008, 2009 Free Software
dnl @ Foundation, Inc.
dnl @ This file is free software; the Free Software Foundation
dnl @ gives unlimited permission to copy and/or distribute it
dnl @ with or without modifications, as long as this notice
dnl @ is preserved.
incr(`4')
dnl @result{}5
decr(`7')
dnl @result{}6
incr()
dnl @error{}m4:stdin:3: empty string treated as 0 in builtin `incr'
dnl @result{}1
decr()
dnl @error{}m4:stdin:4: empty string treated as 0 in builtin `decr'
dnl @result{}-1