A quick grep (for gcd_ and lcm_ in *.*pp) suggests that the following libraries are affected by gcd and lcm namespace change moving from math to integer library. At present, math_fwd.hpp provides some typedefs and declarations needed for these, and a copy of the common factor codes, so nothing may fail immediately, but these duplicate will be removed after at least one release. Chrono Interprocess Math Multiprecision Ratio Rational Units All libraries should use the declarations in integer/integer_fwd.hpp and /integer/common_factor_ct.hpp and /integer/common_factor_rt.hpp. (And there may be documentation changes too?) Something needs to be done ;-) (If you want *me* to resolve anything, then I need write access to your library). Paul --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830