Hello, I have some ideas for config/predef, multiprecision and others. config/predef: What bothers me is the inconsistent nomenclature of several macros. For example, integer: BOOST_HAS_INT128 BOOST_NO_INT64_T float: BOOST_FLOATx_C decimal: ? I think you should definitely generalize that: BOOST_HW_TYPE_AVAILABLE: only if TYPE is supported by the hardware (based on BOOST_HW_SIMD*), but not necessarily by the compiler or selected architecture BOOST_LIB_TYPE_AVAILABLE: TYPE is available from the c++library/compiler For example, float80_t: has HW support on x86 (BOOST_HW_FLOAT80_AVAILABLE is defined), but not on MSVC (BOOST_LIB_FLOAT80_AVAILABLE is not defined then) BOOST_SW_TYPE_AVAILABLE: there is an external emulation of TYPE For example, multiprecision A's complement fixed precision integer (TODO) or "half" by sourceforge Of course, this must be set manually. At least for int/float/decimal 8..512 this should be available. BOOST_HW_MACHINE_SIZE: the real word size of HW BOOST_ARCH_MACHINE_SIZE: the word size of the architecture For example, DOS on AMD Ryzen BOOST_HW_MACHINE_SIZE = 64 and BOOST_ARCH_MACHINE_SIZE = 16 multiprecision/float128_t: there are still many features missing most values in numeric_limits<float128_t> are not constexpr math::constants: i miss log2(2/e/pi/10) etc and i miss BOOST_COMP_VECTOR_EXTENSIONS_AVAILABLE if the compiler supports __attribute__(__vector_size__(...)) and BOOST_COMP_VECTOR_EXTENDED_EXTENSIONS_AVAILABLE if the compiler supports extendet vector extensions (currently only clang/llvm?) and BOOST_ARTIFICIAL __attribute__((artificial)) if supported thx