constexpr explicit text_encoding(string_view enc) noexcept;

Preconditions:

• enc represents a string in the ordinary literal encoding consisting only of elements of the basic character set ([lex.charset]).

• enc.size() <= max_name_length is true.

• enc.contains('\0') is false.

Postconditions:

• If there exists a primary name or alias a of a known registered character encoding such that comp-name(a, enc) is true, mib_ has the value of the enumerator of id associated with that registered character encoding.

  Otherwise, mib_ == id​::​other is true.

• enc.compare(name_) == 0 is true.

constexpr text_encoding(id i) noexcept;

Preconditions: i has the value of one of the enumerators of id.

Postconditions:

• If (mib_ == id​::​unknown || mib_ == id​::​other) is true, strlen(name_) == 0 is true.

  Otherwise, ranges​::​contains(aliases(), string_view(name_)) is true.

constexpr id mib() const noexcept;

constexpr const char* name() const noexcept;

Remarks: name() is an ntbs and accessing elements of name_ outside of the range is undefined behavior.

constexpr aliases_view aliases() const noexcept;

Let r denote an instance of aliases_view.

Otherwise, r is an empty range.

Each element in r is a non-null, non-empty ntbs encoded in the literal character encoding and comprising only characters from the basic character set.

[Note 1:

The order of aliases in r is unspecified.

— end note]

static consteval text_encoding literal() noexcept;

Mandates: CHAR_BIT == 8 is true.

Returns: A text_encoding object representing the ordinary character literal encoding ([lex.charset]).

static text_encoding environment();

Mandates: CHAR_BIT == 8 is true.

Returns: A text_encoding object representing the implementation-defined character encoding scheme of the environment.

On a POSIX implementation, this is the encoding scheme associated with the POSIX locale denoted by the empty string "".

[Note 2:

This function is not affected by calls to setlocale.

— end note]

Recommended practice: Implementations should return a value that is not affected by calls to the POSIX function setenv and other functions which can modify the environment ([support.runtime]).

template<id i> static bool environment_is();

Mandates: CHAR_BIT == 8 is true.

Returns: environment() == i.

static constexpr bool comp-name(string_view a, string_view b);