[boost] regex_match and temporaries

Using valgrind I found an unexpected behavior in regex_match when using temporaries. Although the input parameters allow using temporaries for the string to search in (i was using the variant that takes const std::string&), actually accessing the matches using a boost::smatch will try to look up the data in the already destructed temporary. I could not find a note in the documentation that describes this limitation, I think some clarification would be good. regards, Michael