I've found only two FastCGI libraries for C++. There's the "official" one, and fastcgi++. How is either one better than the other? Do any others exist?
What you probably want is hidden in the contrib
directory of Cgicc package.
fcgi-test.cpp
is an example of how to use cgicc with FastCGI.
Path to the installed fcgi-test.cpp
should be
/usr/share/doc/libcgicc-doc/examples/contrib/fcgi-test.cpp