Sketchy overview of the details:

See also the FAQ section in doc/rxvt.1.txt, and README.configure.

- the options used in the ./reconf script should work. everything else
  might work and might be broken.

- wchar_t MUST be UNICODE or ISO-10646-1 on your system, or various things
  will break down. On GNU/Linux, this is true for all locales, on Solaris,
  this might be true only for locales ending in "@ucs", but you should
  have plenty of them, as there should be a corresponding @ucs-locale for
  every normal locale.

  If you know details for other operating systems, please notify me (in
  general, if your env defines __STDC_ISO_10646__ then everything should
  be fine).

- rxvt will use unicode internally, but does input/output in the current
  locale. so to get a utf-8 terminal, use "LC_CTYPE=en_US.UTF-8 rxvt" or
  equivalent.

- you can specify a different locale to be used for your input method
  using the imLocale ressource or switch, e.g.:
  LC_CTYPE=ja_JP.UTF-8 rxvt -imlocale ja_JP.EUC-JP

- keyboard input is limited by the selected locale (and X's support for
  it), tty input and output likewise. Selection support is independent of
  the locale.

- "-fn" commandline switch and *.font ressource accepts a comma
  seperated list of fontnames:

  x:9x15bold			a x11 font
  9x15bold			the same
  xft:Andale Mono		a xft font
  xft:Andale Mono:pixelsize=20
  9x15bold,terminus-15

- the _first_ font in the list selects the cell width/height. All other
  fonts must be smaller or same sized, or they will be ignored or worse.
  xft fonts will automatically be rescaled, x11-fonts, too, if their
  size is not specified in the XLFD.

- the fonts will be tried in the order given when searching for a font
  to display a specific character. if you are e.g. mainly interested
  in japanese you might want to put a japanese font first to get the
  ascii characters glyphs from it. If you are mainly interested in a text
  terminal and only want to display other characters you should put a
  ascii/is8859 text font first (e.g. "9x15bold") and let rxvt sort it out.

- xft fonts require gobs of memory and generally are slow. try not to
  antialias them ("Font:antialias=false") when possible. Might look
  better, too, as they then match other fonts in weight.

- src/defaultfont.C lists the fallback fonts that are tried when a
  character cannot be displayed with the current list of fonts.

- if the realBold resource has been set, bold fonts will be used to
  display text with the bold attribute; you should specify the bold fonts
  you want to use in the list of fonts after the normal fonts

- otherwise, normal bold text will use reverse video unless the colorBD
  resource has been set. coloured text will use high-intensity colours for
  bold.

Marc <rxvt@plan9.de>