Hello, I would like to submit a strange problem we recently discovered, when using boost_unit_test. This problem only occurs : on Mac OS X, when using gcc 4 with any optimization level other than 0 (-O, -O1, -O2, etc...). I have tested with gcc 4.0.1 (build 5250 coming with Apple XCode 2.2.1), and also gcc 4.0.2 delivered by darwinports, and the problem is the same. On the other hand, it works perfectly on Linux, with gcc 4.0.2 and optimizations. The problem : it occurs when using BOOST_CLASS_TEST_CASE. BOOST_CLASS_TEST_CASE executes a test method of a class/struct instance, so that the class/struct attributes can be used in the test. With a very simple class, named SampleTest, having only -> one int attribute "a" -> a single test function : void sampleTest (), which only displays value of "a" -> a test declared in boost test suite : BOOST_CLASS_TEST_CASE ( & SampleTest::sampleTest, instance), with instance being shared pointer to a instance of sampleTest, instanciated with a given value of "a" passed as constructor argument. It does not work on Mac OS X, with the conditions described above. Everything happens as if BOOST_CLASS_TEST_CASE was not using the correct address in memory for accessing the instance attributes data. Furthermore, the value displayed for a is wrong, but always the same, it is not random at all, which seems to mean that there is a shift in the memory adress being accessed. Below is the complete sample program, for reproducing the problem : ---- file boost_unit_test_gcc4_pb_sample.cpp --- #include <iostream> #include <boost/test/unit_test.hpp> using boost::unit_test_framework::test_suite; using boost::unit_test_framework::test_case; using namespace std; class SampleTest { public: SampleTest (int val) : a (val) { } int a; void sampleTest () { std::cout << "a : " << a << std::endl; BOOST_CHECK_EQUAL (a, 12345); } }; test_suite* init_unit_test_suite( int argc, char* argv[] ) { test_suite* test= BOOST_TEST_SUITE( "Sample test" ); boost::shared_ptr<SampleTest> instance (new SampleTest (12345)); test->add (BOOST_CLASS_TEST_CASE ( & SampleTest::sampleTest, instance)); return test; } ---- end-of-file boost_unit_test_gcc4_pb_sample.cpp --- * Command used for compiling : BOOST_PATH=<path-to-your-boost-install> /usr/bin/g++-4.0 -O2 -I${BOOST_PATH}/include -L${BOOST_PATH}/lib - lboost_unit_test_framework boost_unit_test_gcc4_pb_sample.cpp -o boost_unit_test_gcc4_pb_sample When compiled when the above command, and running the program on Mac OS X : export DYLD_LIBRARY_PATH=${BOOST_PATH}/lib ./boost_unit_test_gcc4_pb_sample The result is the following : ---- Running 1 test case...a : 13691 boost_unit_test_gcc4_pb_sample.cpp(18): error in " SampleTest::sampleTest": check a == 12345 failed [13691 != 12345] *** 1 failure detected in test suite "Sample test" --- We see that value of "a" is wrong. When compiled without optimization (-O0), and running, the result is : ---- Running 1 test case...a : 12345 *** No errors detected ---- Everything is right in this case. Has anyone some experience using Boost unit_test framework on Mac OS X, using gcc 4, and already experienced this kind of problems ? Any help would be greatly appreciated ! Regards, Anand