If my previous post makes it to the mailing list, please ignore it (I figured out some of the original confusion). Here's the problem I'm left with:- A couple of days ago I installed libboost (v1.40) using the Windows setup.exe file. To get myself started I decided to build the regex example that I found here:- http://www.cs.brown.edu/~jwicks/boost/libs/regex/doc/introduction.html My installation contains DLLs called:- boost_regex-vc80-mt-1_40.dll and boost_regex-vc80-mt-gd-1_40.dll along with their associated link libs - and here's the example, as I built it:- #include <string> #include using namespace std; using namespace boost; bool validate_card_format(const string s) { static const boost::regex e("(\\d{4}[- ]){3}\\d{4}"); return regex_match(s, e); } // and further on, I call the above function.... bool bb = validate_card_format("1111 2222 3333 4444"); If I link my app to boost_regex-vc80-mt-gd-1_40.lib (or if I don't link it to boost at all) the app won't run. In either case if I try to launch my app I see a dialog box telling me that the configuration is incorrect (possibly a problem with manifests?) OTOH If I link my app to boost_regex-vc80-mt-1_40.lib, I get a crash at the above call - i.e. at 'bb = validate_card_format("1111 2222 3333 4444");' The crash is caused by an unhandled exception in 'basic_regex::assign'. The exception occurs at the call to 'do_assign()' and I get this message:- boost::exception_detail::clone_implstd::runtime_error

at memory location 0x0012f4e4.

I'm guessing that I should have configured something between installing boost and starting to use it. Have I missed a step out somewhere? Thanks, John