http://www.boost.org/libs/utility/enable_if.html#htoc9 explains that some compilers (e.g. GCC 3.2) diagnose two functions as ambiguous if the only distinguishing factor is a different condition in an enabler and offers some workarounds. Is there a BOOST_ macro that's defined when these workarounds need to be applied? If not, any help putting such a macro together would be gratefully received! Thanks, Gareth ************************************************************************ The information contained in this message or any of its attachments may be confidential and is intended for the exclusive use of the addressee(s). Any disclosure, reproduction, distribution or other dissemination or use of this communication is strictly prohibited without the express permission of the sender. The views expressed in this email are those of the individual and not necessarily those of Sony or Sony affiliated companies. Sony email is for business use only. This email and any response may be monitored by Sony to be in compliance with Sony�s global policies and standards