(i think i might have mentioned this before, but it still happens with the current code, so...) Using Variant on VC9 with warning level 4 can result in an unreferenced parameter warning: boost/variant/variant.hpp(289) : warning C4100: 'operand' : unreferenced formal parameter This can be silenced by extending the existing Borland workaround to apply to VC as well. For example, change the existing: #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x0551)) operand; // suppresses warnings to #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x0551)) || BOOST_WORKAROUND(BOOST_MSVC, >= 1400) operand; // suppresses warnings Thanks, Richard Webb -- View this message in context: http://www.nabble.com/-variant--unreferenced-formal-parameter-warning-from-V... Sent from the Boost - Dev mailing list archive at Nabble.com.