dnl @ ../doc/m4.texinfo:1755: 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.
ifdef(`foo', ``foo' is defined', ``foo' is not defined')
dnl @result{}foo is not defined
define(`foo', `')
dnl @result{}
ifdef(`foo', ``foo' is defined', ``foo' is not defined')
dnl @result{}foo is defined
ifdef(`no_such_macro', `yes', `no', `extra argument')
dnl @error{}m4:stdin:4: Warning: excess arguments to builtin `ifdef' ignored
dnl @result{}no