valgrind 3.3.0 complains about uninitialized memory in BoostTest 1.35.0: ==31740== Syscall param sigaltstack(ss) points to uninitialised byte(s) ==31740== at 0x413D811: sigaltstack (in /lib/tls/libc-2.3.2.so) ==31740== by 0x80863D8: boost::execution_monitor::catch_signals(boost::unit_test::callback0<int> const&) (in Application) ==31740== by 0x80864AB: boost::execution_monitor::execute(boost::unit_test::callback0<int> const&) (in Application) ==31740== by 0x8084AD7: boost::unit_test::unit_test_monitor_t::execute_and_translate(boost::unit_test::test_case const&) (in Application) ==31740== by 0x8081492: boost::unit_test::framework_impl::visit(boost::unit_test::test_case const&) (in Application) ==31740== by 0x8076684: boost::unit_test::traverse_test_tree(boost::unit_test::test_suite const&, boost::unit_test::test_tree_visitor&) (in Application) ==31740== by 0x8076658: boost::unit_test::traverse_test_tree(boost::unit_test::test_suite const&, boost::unit_test::test_tree_visitor&) (in Application) ==31740== by 0x8080443: boost::unit_test::framework::run(unsigned long, bool) (in Application) ==31740== by 0x806E093: boost::unit_test::unit_test_main(boost::unit_test::test_suite* (*)(int, char**), int, char**) (in Application) The attached patch fixes this error by initializing the structure passed to syscall sigaltstack(). Best regards, Peter.