Hello Matt, Sorry for submitting a bug report this way. (Having problems with my GitHub account at the moment). Code: Attachment (gcc 13.2 -std=gnu++23 -O3 -Wall -fanalyzer) Errors (normal) - Missing sign - Hex exponent is wrong - Hex is completely wrong - Accuracy is not correct - Error code deviates from the standard ... The backup functions via (quadmath)snprintf do not work. Errors (critical) - If the buffer is too small (e.g. set the array size to 3) there are a lot of buffer overflows. Especially with value ±nan/±inf. The functions should therefore always be structured in the same way: Auxiliary function inline constexpr bool is_valid_range(const char*const first, const char*const last) noexcept { return (first!=nullptr && last!=nullptr) ? first < last : false; } Pseudocode to_chars(...) // FP { to_chars_result result{last, std::errc::value_too_large}; if (is_valid_range(first, last)) [[likely]] { const size_t size = size_t(last - first); if (inf or nan) [[unlikely]] { if (size is large enough) { copy the string values into the range result = ...; Here you could also use #define to specify whether the string values are compatible with the standard or not. "±inf", "±nan" or https://develop.charconv.cpp.al/#to_chars_usage_notes_for_to_chars_for_float... } } else { convert, detail::implemantation(first, size, ...) result = ...; } } return result; } to_chars(...) // INT { to_chars_result result{last, std::errc::value_too_large}; if (is_valid_range(first, last)) [[likely]] { const size_t size = size_t(last - first); convert, detail::implemantation(first, size, ...) result = ...; } return result; } This can be achieved with templates and typetraits: FP boost::is_floating_point still does not contain any C++23 types. template <typename Type> BOOST_NOINLINE typename std::enable_if::type to_chars(char*const first, char*const last, const Type value, const chars_format format, const int precision) noexcept; template <type name Type> BOOST_NOINLINE typename std::enable_if::type to_chars(char*const first, char*const last, const Type value, const chars_format format) noexcept; INT (boost)is_integer is unfortunately still missing. template <type name Type> BOOST_NOINLINE typename std::enable_if::type to_chars(char*const first, char*const last, const Type value, const int base = 10) noexcept; regards Gero