std::chars_format

From cppreference.com
< cpp‎ | utility
Defined in header <charconv>
enum class chars_format {

    scientific = /*unspecified*/,
    fixed = /*unspecified*/,
    hex = /*unspecified*/,
    general = fixed | scientific

};
(since C++17)

A BitmaskType used to specify floating-point formatting for std::to_chars and std::from_chars

See also

(C++17)
converts an integer or floating-point value to a character sequence
(function)
converts a character sequence to an integer or floating-point value
(function)