Describes implementation-defined aspects of the Arm® C compiler and C library relating to characters, as required by the ISO C standard.
- The number of bits in a byte (3.6).
- The number of bits in a byte is 8.
- The values of the members of the execution character set (5.2.1).
- The values of the members of the execution character set are all the code
points defined by ISO/IEC 10646.
- The unique value of the member of the execution character set produced for each of the
standard alphabetic escape sequences (5.2.2).
- Character escape sequences have the following values in the execution character set:
|New line (line feed)
- The value of a char object into which has been stored any character other than a member of
the basic execution character set (6.2.5).
- The value of a
char object into which has been
stored any character other than a member of the basic execution character set is
the least significant 8 bits of that character, interpreted as unsigned.
- Which of signed char or unsigned char has the same range, representation, and behavior as
char (6.2.5, 220.127.116.11).
- Data items of type
char are unsigned by default. The type
char has the same range, representation, and behavior as
- The mapping of members of the source character set (in character constants and string
literals) to members of the execution character set (18.104.22.168, 22.214.171.124).
- The execution character set is identical to the source character set.
- The value of an integer character constant containing more than one character or containing
a character or escape sequence that does not map to a single-byte execution
- In C all character constants have type
int. Up to
four characters of the constant are represented in the integer value. The last
character in the constant occupies the lowest-order byte of the integer value.
Up to three preceding characters are placed at higher-order bytes. Unused bytes
are filled with the
- The value of a wide-character constant containing more than one multibyte
character or a single multibyte character that maps to multiple members of
the extended execution character set, or containing a multibyte character or
escape sequence not represented in the extended execution character set
- If a wide-character constant contains more than one multibyte character,
all but the last such character are ignored.
- The current locale used to convert a wide-character constant consisting of
a single multibyte character that maps to a member of the extended execution
character set into a corresponding wide-character code (126.96.36.199).
- Mapping of wide-character constants to the corresponding wide-character
code is locale independent.
- Whether differently-prefixed wide string literal tokens can be concatenated and, if so, the
treatment of the resulting multibyte character sequence (6.4.5).
- Differently prefixed wide string literal tokens cannot be concatenated.
- The current locale used to convert a wide string literal into corresponding
wide-character codes (6.4.5).
- Mapping of the wide-characters in a wide string literal into the
corresponding wide-character codes is locale independent.
- The value of a string literal containing a multibyte character or escape sequence not
represented in the execution character set (6.4.5).
- The compiler does not check if the value of a multibyte character or an
escape sequence is a valid ISO/IEC 10646 code point. Such a value is encoded
like the values of the valid members of the execution character set,
according to the kind of the string literal (character or wide-character).
- The encoding of any of
char32_t where the corresponding standard
encoding macro (
is not defined (188.8.131.52).
__STDC_ISO_10646__ is not defined. Nevertheless
every character in the Unicode required set, when stored in an object of
wchar_t, has the same value as the short
identifier of that character.
__STDC_UTF_32__ are defined.