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character literal

From cppreference.com
< cpp‎ | language

[edit] Syntax

' c-char ' (1)
u8 ' c-char ' (since C++17) (2)
u ' c-char ' (since C++11) (3)
U ' c-char ' (since C++11) (4)
L ' c-char ' (5)
' c-char-sequence ' (6)

where

  • c-char is either
  • a character from the basic source character set minus single-quote ('), backslash (\, or the newline character,
  • escape sequence, as defined in escape sequences
  • universal character name, as defined in escape sequences
  • c-char-sequence is a sequence of two or more c-chars.
1) narrow character literal or ordinary character literal, e.g. 'a' or '\n' or '\13'. Such literal has type char and the value equal to the representation of c-char in the execution character set. If c-char is not representable in the execution character set, the literal has type int and implementation-defined value
2) UTF-8 character literal, e.g. u8'a'. Such literal has type char and the value equal to ISO 10646 code point value of c-char, provided that the code point value is representable with a single UTF-8 code unit. If c-char is not in Basic Latin or C0 Controls Unicode block, the program is ill-formed.
3) UCS-2 character literal, e.g. u'貓', but not u'🍌' (u'\U0001f34c'). Such literal has type char16_t and the value equal to the value of c-char in Unicode, if it is a part of the basic multilingual plane. If c-char is not part of the BMP, the program is ill-formed.
4) UCS-4 character literal, e.g. U'貓' or U'🍌'. Such literal has type char32_t and the value equal to the value of c-char in Unicode.
5) wide character literal, e.g. L'β' or L'貓. Such literal has type wchar_t and the value equal to the value of c-char in the execution wide character set. If c-char is not representable in the execution character set (e.g. a non-BMP value on Windows where wchar_t is 16-bit), the value of the literal is implementation-defined.
6) Multicharacter literal, e.g. 'AB', has type int and implementation-defined value.

[edit] Notes

Many implementations of multicharacter literals use the values of each char in the literal to initialize successive bytes of the resulting integer, in big-endian order, e.g. the value of '\1\2\3\4' is 0x1020304