[Boost-users] BOOST_CHECK_PREDICATE vs BOOST_WARN_PREDICATE

The documentation page for the PREDICATE testing macros gives quite different syntax for the WARN vs CHECK methods: BOOST_WARN_PREDICATE( moo, (12)(i)(j) ); BOOST_CHECK_PREDICATE( std::not_equal_to<int>(), 2, (i,17) ); Since BOOST_WARN_PREDICATE and BOOST_CHECK_PREDICATE are only slight variants of one another, I'm confused as to why the syntax differs so much. Can anyone shed some light on this for me? Thanks, Alex