Hi, While working on a project of ours I have come accross this problem using boost-1.32 on Mac OS X 10.4: It appears to be related to the regex library. <snip> Making all in mantrad source='mantra_request_admin.cpp' object='mantra_request_admin.o' libtool=no \ depfile='.deps/mantra_request_admin.Po' tmpdepfile='.deps/mantra_request_admin.TPo' \ depmode=gcc3 /bin/sh ../../depcomp \ g++ -DHAVE_CONFIG_H -I. -I. -I../.. -I.. -I../libs/sockets -I../libs/sigaware -I../libs/threadpool -Wall -g -D_THREAD_SAFE -c -o mantra_request_admin.o `test -f 'mantra_request_admin.cpp' || echo './'`mantra_request_admin.cpp /opt/local/include/boost/regex/v4/char_regex_traits.hpp: In member function 'uint_fast32_t boost::deprecated::char_regex_traits_i<wchar_t>::lookup_classname(const wchar_t*, const wchar_t*) const': /opt/local/include/boost/regex/v4/char_regex_traits.hpp:68: error: 'boost::re_detail::c_traits_base::<anonymous enum>' is/uses anonymous type /opt/local/include/boost/regex/v4/char_regex_traits.hpp:68: error: trying to instantiate 'template<class T> struct boost::is_integral' make[3]: *** [mantra_request_admin.o] Error 1 make[2]: *** [all-recursive] Error 1 make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2 </snip> The thing is I have not had this problem on any other platform, or indeed 2 other Mac's running an (as far as I'm aware) identical setup. Does anyone have any ideas as to the possible cause of this? Many Thanks Chris This message has been checked for viruses but the contents of an attachment may still contain software viruses, which could damage your computer system: you are advised to perform your own checks. Email communications with the University of Nottingham may be monitored as permitted by UK legislation.