What does this warning “** WARNING ** TrueType post table name index 32768 > 32767” mean?

Question

I'm new to TeX and trying to compile this code:

\documentclass{article}
\usepackage{xeCJK}
\setCJKmainfont{WenQuanYi Zen Hei Mono}
\begin{document}
你好，\TeX！
\end{document}

I get the pdf fine, but confused by the warning.

$ xelatex t.tex 
This is XeTeX, Version 3.1415926-2.3-0.9997.5 (TeX Live 2011)
 restricted \write18 enabled.
entering extended mode
(./t.tex
LaTeX2e <2009/09/24>
Babel <v3.8l> and hyphenation patterns for english, dumylang, nohyphenation, ge
rman-x-2009-06-19, ngerman-x-2009-06-19, afrikaans, ancientgreek, ibycus, arabi
c, armenian, basque, bulgarian, catalan, pinyin, coptic, croatian, czech, danis
h, dutch, ukenglish, usenglishmax, esperanto, estonian, ethiopic, farsi, finnis
h, french, galician, german, ngerman, swissgerman, monogreek, greek, hungarian,
 icelandic, assamese, bengali, gujarati, hindi, kannada, malayalam, marathi, or
iya, panjabi, tamil, telugu, indonesian, interlingua, irish, italian, kurmanji,
 lao, latin, latvian, lithuanian, mongolian, mongolianlmc, bokmal, nynorsk, pol
ish, portuguese, romanian, russian, sanskrit, serbian, serbianc, slovak, sloven
ian, spanish, swedish, turkish, turkmen, ukrainian, uppersorbian, welsh, loaded
.
(/usr/local/texlive/2011/texmf-dist/tex/latex/base/article.cls
Document Class: article 2007/10/19 v1.4h Standard LaTeX document class
(/usr/local/texlive/2011/texmf-dist/tex/latex/base/size10.clo))
(/usr/local/texlive/2011/texmf-dist/tex/xelatex/xecjk/xeCJK.sty
(/usr/local/texlive/2011/texmf-dist/tex/generic/ifxetex/ifxetex.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/fontspec/fontspec.sty
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/expl3.sty
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3names.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/etex-pkg/etex.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3basics.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3expan.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3tl.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3int.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3quark.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3seq.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3toks.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3prg.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3clist.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3token.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3prop.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3msg.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3io.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3skip.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3box.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3keyval.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3keys.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3precom.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3xref.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3file.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3fp.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/expl3/l3luatex.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/tools/calc.sty))
(/usr/local/texlive/2011/texmf-dist/tex/latex/xpackages/xbase/xparse.sty)
(/usr/local/texlive/2011/texmf-dist/tex/generic/kastrup/binhex.tex)
(/usr/local/texlive/2011/texmf-dist/tex/latex/xkeyval/xkeyval.sty
(/usr/local/texlive/2011/texmf-dist/tex/generic/xkeyval/xkeyval.tex
(/usr/local/texlive/2011/texmf-dist/tex/generic/xkeyval/keyval.tex)))
(/usr/local/texlive/2011/texmf-dist/tex/latex/fontspec/fontspec-patches.sty
(/usr/local/texlive/2011/texmf-dist/tex/latex/base/fixltx2e.sty))
(/usr/local/texlive/2011/texmf-dist/tex/latex/base/fontenc.sty
(/usr/local/texlive/2011/texmf-dist/tex/latex/euenc/eu1enc.def)
(/usr/local/texlive/2011/texmf-dist/tex/latex/euenc/eu1lmr.fd))
(/usr/local/texlive/2011/texmf-dist/tex/xelatex/xunicode/xunicode.sty)
(/usr/local/texlive/2011/texmf-dist/tex/latex/fontspec/fontspec.cfg)))
No file t.aux.
[1] (./t.aux)
** WARNING ** TrueType post table name index 32768 > 32767
 )
Output written on t.pdf (1 page).
Transcript written on t.log.

In the log, it says:

 fontspec info: Font WenQuanYi Zen Hei Mono does not contain any OpenType `Scri
pt' information.

\g_fontspec_family_WenQuanYi Zen Hei Mono_int=\count177
 fontspec info: Defining font family 'WenQuanYiZenHeiMono(0)' for font 'WenQuan
Yi Zen Hei Mono' with options [].

\g_fontspec_WenQuanYiZenHeiMono(0)_prop=\toks37
 fontspec info: Defining shape 'normal' with NFSS spec.:
(fontspec)  <->"WenQuanYi Zen Hei Mono/ICU:"

 fontspec info: Could not resolve font WenQuanYi Zen Hei Mono/B (it probably do
esn't exist).

 fontspec info: Could not resolve font WenQuanYi Zen Hei Mono/I (it probably do
esn't exist).

 fontspec info: Could not resolve font WenQuanYi Zen Hei Mono/BI (it probably d
oesn't exist).

My question is if XeLaTeX can't find the wqy font, how can the pdf be successfully generated?

Answer 1

The font is found, but fontspec can't identify bold (/B) and italic versions (/I). That is not a problem as it will in such cases fall back to the normal font version. The TrueType post table name index warning is – as far as I know – not critical.