Input method related environment variables
This page introduce the meaning of following environment variables. You don't need to understand it to use Fcitx, but it might help when you meet some problem, and examine yourself to check what goes wrong.
XMODIFIERS
This variable affects XIM only. The format is
XMODIFIERS=@im=<xim server name>
When XIM server starts, it register a name, which will be used here. The name can not be same as other XIM server, so you cannot run two Fcitx under same X server. In general case, the XIM server name of Fcitx will be fcitx.
So the settings for Fcitx will be
XMODIFIERS=@im=fcitx
GTK_IM_MODULE
This will override the system automatic gtk im module selection. By default gtk select im module by the language provided by im module. Fcitx declares that it support "zh:ja:ko:*". And this information will be record in a file, on most linux system it's /etc/gtk-2.0/gtk.immodules and /etc/gtk-3.0/gtk.immodules, or suffixed with -32 or -64.
{{warning|After Debian goes multiarch, they will use different file. /usr/lib/<arch>/gtk-{2,3}.0 }} You need to use
gtk-query-immodules-2.0 > <gtk-2.0 immodule file>
or
gtk-query-immodules-3.0 --update-cache
to update those file. Otherwise new im module will not be recognized.
If no im module specified by GTK_IM_MODULE is found, it will fallback to auto select method.
QT_IM_MODULE
Qt's im module is similar with Gtk, but don't need extra file to recognize. If QT_IM_MODULE is not specified, qtconfig (Ubuntu/Debian qtconfig-qt4) can be used to configure the default one.
Otherwise it will be override by QT_IM_MODULE.
LC_CTYPE
System locale should not be changed in all case. It might brings unpredictable effect.
This should only be used in one case, that is emacs. Emacs has a historical bug, that under en_US.UTF-8 or similar locale, it will never use XIM (Though emacs is a gtk app, it use XIM). The only way to walkaround this is to use LC_CTYPE to fix this.
To only set this with emacs, run emacs with
LC_CTYPE=zh_CN.UTF-8 emacs
It will not effect the display language of emacs.