(This is originally a private mail reposted with hope to get more feedback. Boost.Exception http://www.revergestudios.com/boost-exception/boost-exception.htm is a library waiting in review queue.) Hello Emil, When using your library I met 2 problems: * GCC 3.4.2, shipped with MingW (and part of wxDevC++ IDE, on Windows) fails to recognize boost::exception::what() as overide of std::exception::what() and ends with an error. I was not able to find what could be the problem, everything looked OK. At the end, not knowing better, I changed the name to what2(). * When using GCC 4.1.1 which has ability to hide symbols in a shared library by default I run in the problem described in http://gcc.gnu.org/wiki/Visibility in section "Problems with C++ exceptions (please read!)". Currently, I reenabled exporting all symbols by default. The OS is Linux. /Pavel