>Can anybody help me find documents about the libraries of c/c++, java
>Xlib, Xtk, and othe Xwindow toolkit?
Yes. Try the following
Linux C libary: GNU C library manual (PIY or buy a copy form the FSF).
Linux C++ linary: G++ library manual (PIY or buy a copy from the FSF).
Xlib: Volumes 1 & 2 of the ORA X windows series (the proigrammers guide
is highly recommened, even for those who usually just get the
Xt: Volumes 4 & 5 of the ORA X windows series (ditto concerning the
tcl/tk: Tcl and the tk toolkit
java: Lots fo choice on this one. Visit your local bookshop.
X extensions: Volume 9 of the ORA X windows series.
I have all but the last two, with PIY version of the GNU manuals in lever
arch files. I also have good stuff like volumes 1 to 3 of Knuth,
"Introduction to Algorithms" (Corrmmen, Leison and Rivest), The TeXBOOK
(Knuth), LaTeX: a dcoument perpation system (Lamport) and The*
companion. (This is just a small selection from my book shelves).