Spirit has been accepted into boost, so i guess this is the correct group for posting this question. Trying to build the simplexml example, i get the following output from msvc6 sp5 (and similar ones from msvc 7): -------------------Configuration: simplexml - Win32 Debug-------------------- Compiling... ****** {BD Software Proxy CL v2.26} STL Message Decryption is Off ****** simplexml.cpp f:\swd\boost\boost\spirit\core\impl\primitives.ipp(88) : warning C4244: 'return' : conversion from 'int' to 'char', possible loss of data f:\swd\boost\boost\spirit\core\impl\primitives.ipp(89) : warning C4244: 'return' : conversion from 'int' to 'char', possible loss of data f:\swd\boost\boost\spirit\iterator\impl\msvc_ps_helper.hpp(60) : error C2371: 'true_t' : redefinition; different basic types f:\swd\boost\boost\spirit\core\basics.hpp(38) : see declaration of 'true_t' f:\swd\boost\boost\spirit\iterator\impl\msvc_ps_helper.hpp(65) : error C2371: 'false_t' : redefinition; different basic types f:\swd\boost\boost\spirit\core\impl\basics.ipp(23) : see declaration of 'false_t' f:\swd\boost\boost\spirit\iterator\impl\multi_pass_msvc.hpp(402) : fatal error C1903: unable to recover from previous error(s); stopping compilation Error executing cl.exe. I downloaded the spirit-only-1.5.1.zip and included it in my boost directory tree. Any ideas?