I have an up-to-date Archlinux system with a standard gcc 4.4.3. I wish to use a library that in turn uses Boost.Fusion. I get compilation errors for Boost.Fusion 1.41 and 1.42 (version 1.40 and 1.37 are ok). Simple test program to reproduce: #include #include <iostream> int main() { std::cout << "Hello world"; } The first error that I get is: boost/fusion/functional/adapter/unfused_generic.hpp:54 error: a function call cannot appear in a constant-expression boost/fusion/functional/adapter/unfused_generic.hpp:54 error: template argument 1 is invalid Google has not helped me to resolve my problems. Any help is greatly appreciated. Theo.