dnl @ ../doc/m4.texinfo:3705: Origin of test
dnl @ Copyright (C) 2006 Free Software Foundation
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