Hello The sprintf function reference in the using directive at regex_workaround.hpp is declared in stdio.h or cstdio which is not included. This missing header inclusion makes build of boost regex lib impossible with msvc-stlport toolset and surely with many other STLport toolsets. I try to remove the using directive as this function is not used in this file but it is in regex lib sources so the fix is really to add the header inclusion. Bests *** regex_workaround.hpp.orig Thu Aug 25 05:32:32 2005 --- regex_workaround.hpp Thu Aug 25 05:32:50 2005 *************** *** 22,27 **** --- 22,28 ---- #include <new> #include <cstring> + #include <cstdio> #include <cstdlib> #include <cstddef> #include <cassert>