When I compile my code with gcc version 5.2.0 (x86_64-posix-seh-rev0, Built by MinGW-W64 project), I have annoying warnings with boost/utf and boost/asio (1.59). For example if I compile this simple file : #define BOOST_TEST_MODULE ExactSuite #include "boost/test/unit_test.hpp" I get : c:\Users\Renaud\nest\external\boost_1_59_0/boost/test/unit_test_log.hpp:130:28: warning: 'boost::unit_test::{anonymous}::unit_test_log' defined but not used [-Wunused-variable] BOOST_TEST_SINGLETON_INST( unit_test_log ) I can add #pragma GCC diagnostic ignored "-Wunused-variable" just before the include but it seems strange (and I have to do it in few other files). Does someone have similar problem ? or a better fix ?