The program below crashes when compiled and executed in Windows using MSVC8. The crash happens in boost::sub_match::str(). It seems that the internal structure m_subs gets somehow corrupted. The crash disappears when passing the const reference fileName instead of it->path().filename(). I have no idea why this should make any difference. The program expects a directory on the command line. Just put an empty file called "AAA-0.txt" in this directory. Any help is appreciated. Regards, Peter. #include <iostream> #include <boost/filesystem/path.hpp> #include <boost/filesystem/convenience.hpp> #include <boost/regex.hpp> int main(int argc, char** argv) { try { if (argc==2) { const boost::filesystem::path p(argv[1]); const boost::regex regEx("^([A-Za-z0-9_]+)-(.*)\\.txt$"); boost::smatch match; for (boost::filesystem::directory_iterator it(p);it!=boost::filesystem::directory_iterator();++it) { const std::string& fileName=it->path().filename(); if (boost::regex_match(it->path().filename(),match,regEx)) // <- using fileName makes the crash disappear { const std::string projectName=match.str(1); // <- here it crashes } } // for return 0; } } catch (const std::exception& e) { std::cout << e.what() << std::endl; } return 1; }