19 General utilities library [utilities]

19.15 Metaprogramming and type traits [meta]

19.15.9 Endian [meta.endian]

Two common methods of byte ordering in multibyte scalar types are big-endian and little-endian in the execution environment.
Big-endian is a format for storage of binary data in which the most significant byte is placed first, with the rest in descending order.
Little-endian is a format for storage of binary data in which the least significant byte is placed first, with the rest in ascending order.
This subclause describes the endianness of the scalar types of the execution environment.
enum class endian { little = see below, big = see below, native = see below };
If all scalar types have size 1 byte, then all of endian::little, endian::big, and endian::native have the same value.
Otherwise, endian::little is not equal to endian::big.
If all scalar types are big-endian, endian::native is equal to endian::big.
If all scalar types are little-endian, endian::native is equal to endian::little.
Otherwise, endian::native is not equal to either endian::big or endian::little.