Robert Ramey wrote:
Hmmm - but why is it a mistake?
Well it's harmless, but basically the auto-link header *cannot* be include guarded because it really does have to be included multiple times, albeit normally for different libraries. So if you include it multiple times for the same lib, you will - if you have diagnostic messages turned on - get two messages rather than one. But that's it, other than that it's harmless. To prevent the multiple diagnostics just add your own include serialisation-specific guard around it: #ifndef BOOST_SERIALISATION_AUTO_LINKED #define BOOST_SERIALISATION_AUTO_LINKED // auto line setup goes here #endif and repeat in all the places where you need it. Or factor out into a separate header of course. John.