I get a compiler warning when using BOOST_CHECK_EQUAL in conjunction with BOOST_AUTO_UNIT_TEST. The code and warning are below. Anyone know what I'm doing to cause the warning? Environment: Windows XP with MS VS 2003 #define BOOST_AUTO_TEST_MAIN #include <boost/test/auto_unit_test.hpp> class MyTest { public: MyTest( int newVal = 3 ) : a (newVal) {} int GetA() {return(a);} protected: int a; }; MyTest test1; // _____________________________________ BOOST_AUTO_UNIT_TEST( TestCase1 ) { int b = test1.GetA(); BOOST_CHECK_EQUAL( b, 1 ); } The warning is: c:\Boost\include\boost-1_32\boost\test\detail\wrap_stringstream.hpp(69) : warning C4267: 'argument' : conversion from 'size_t' to 'unsigned int', possible loss of data c:\Boost\include\boost-1_32\boost\test\test_tools.hpp(435) : see reference to function template instantiation 'boost::basic_wrap_stringstream<CharT> &boost::operator <<<char,size_t>(boost::basic_wrap_stringstream<CharT> &,const T &)' being compiled with [ CharT=char, T=size_t ] m:\jclaybau_InWork_view\CHAMELEON\SoftwareDevelopmentFolder\Source\AM\Test\AMTest\AMTest.cpp(20) : see reference to function template instantiation 'bool boost::test_tools::tt_detail::equal_and_continue_impl<int,int>(const Left &,const Right &,boost::wrap_stringstream &,boost::test_tools::const_string,size_t,boost::unit_test::log_level,size_t)' being compiled with [ Left=int, Right=int ]