How can Emacs tell if it's started with Xwindow?

[Wang Yin]

Hi,

I want to define some font in my .emacs file as:

(create-fontset-from-fontset-spec
 "-adobe-courier-medium-r-*-*-14-*-*-*-*-*-fontset-wangyin,
        chinese-gb2312:-*-simsun-medium-r-*--16-*-*-*-*-*-gbk-0,
        
mule-unicode-0100-24ff:-misc-fixed-medium-r-normal--16-*-*-*-*-*-iso10646-1,
        korean-ksc5601:-*-medium-r-normal-*-16-*-ksc5601*-*,
        chinese-cns11643-5:-*-simsun-medium-r-*--16-*-*-*-*-*-gbk-0,
        chinese-cns11643-6:-*-simsun-medium-r-*--16-*-*-*-*-*-gbk-0,
        chinese-cns11643-7:-*-simsun-medium-r-*--16-*-*-*-*-*-gbk-0" t)

(setq default-frame-alist
        (append
        '((font . "fontset-wangyin"))
        default-frame-alist))


I think this is more flexible than put this stuff in
.Xdefaults.

But I have a problem now. If Emacs is started with -nw
switch, it will report error.

How can I add a predicate to tell Emacs if we are in X?


-- 
Wang Yin
DA Lab, Tsinghua University,
100084
Beijing China