Oops, a bit of a rookie error. Thanks John. So to summarise for those that search the archives: As per "Link Your Program to a Boost program" ( http://www.boost.org/doc/libs/1_45_0/more/getting_started/unix-variants.html...), and other basic gcc/g++ documentation, the example "Using with MPR / GMP - a High-Precision Floating-Point Library" ( http://www.boost.org/doc/libs/1_45_0/libs/math/doc/sf_and_dist/html/math_too... ): boost_mpfr_example.cpp: #include <boost/math/bindings/mpfr.hpp> #include <boost/math/special_functions/gamma.hpp> int main() { mpfr_class::set_dprec(500); // 500 bit precision // // Note that the argument to tgamma is an expression template, // that's just fine here: // mpfr_class v = boost::math::tgamma(sqrt(mpfr_class(2))); std::cout << std::setprecision(50) << v << std::endl; } Should be compiled and linked with the following command: g++ -I/path/to/boost_1_45_0 boost_mpfr_example.cpp -o boost_mpfr_example -lgmpfrxx -lmpfr -lgmpxx -lgmp On Ubuntu 10.10 the following packages (or source) are needed: - MPFR 3.0.0-2 (ubuntu packages: libmpfr-dev, libmpfr4), - gmp 4.3.2 (libgmp3-dev, libgmp3c2, libgmpxx4ldbl), - gmpfrxx (http://math.berkeley.edu/~wilken/code/gmpfrxx/). Running ./boost_mpfr_example should give: 8.8658142871925912508091761239199431116828551763805e-1 cheers, Novak.