C 词法语法

令牌

token:
 keyword
 identifier
 constant
 string-literal
 punctuator

preprocessing-token:
 header-name
 identifier
 pp-number
 character-constant
 string-literal
 punctuator
 不能成为上述项目之一的每个非空白字符

关键字

keyword：以下项之一
 auto break case char const continue
 default do double else enum extern
 float for goto if inline int long
 register restrict return short signed
 sizeof static struct switch typedef union
 unsigned void volatile while _Alignas
 _Alignof _Atomic _Bool _Complex _Generic
 _Imaginary _Noreturn _Static_assert
 _Thread_local

有关其他 Microsoft 专用的关键字的列表，请参阅 C 关键字。

标识符

identifier:
 identifier-nondigit
 identifier identifier-nondigit
 identifier digit

identifier-nondigit:
 nondigit
 universal-character-name
 其他实现定义的字符

nondigit：以下项之一
 _ a b c d e f g h i j k l m
 n o p q r s t u v w x y z
 A B C D E F G H I J K L M
 N O P Q R S T U V W X Y Z

digit：以下项之一
 0 1 2 3 4 5 6 7 8 9

universal-character-name:
 \u hex-quad
 \U hex-quad hex-quad

hex-quad:
 hexadecimal-digit hexadecimal-digit hexadecimal-digit hexadecimal-digit

常量

constant:
 integer-constant
 floating-constant
 enumeration-constant
 character-constant

integer-constant:
 decimal-constantinteger-suffix_opt
 binary-constant¹integer-suffix_opt
 octal-constantinteger-suffix_opt
 hexadecimal-constantinteger-suffix_opt

decimal-constant:
 nonzero-digit
 decimal-constant digit

binary-constant：¹
 binary-prefix binary-digit
 binary-constant binary-digit

binary-prefix¹：以下项之一
 0b 0B

binary-digit¹：以下项之一
 0 1

octal-constant:
 0
 octal-constant octal-digit

hexadecimal-constant:
 hexadecimal-prefix hexadecimal-digit
 hexadecimal-constant hexadecimal-digit

hexadecimal-prefix：以下项之一
 0x 0X

nonzero-digit：以下项之一
 1 2 3 4 5 6 7 8 9

octal-digit：以下项之一
 0 1 2 3 4 5 6 7

hexadecimal-digit：以下项之一
 0 1 2 3 4 5 6 7 8 9
 a b c d e f
 A B C D E F

integer-suffix:
 unsigned-suffixlong-suffix_opt
 unsigned-suffixlong-long-suffix_opt
 long-suffixunsigned-suffix_opt
 long-long-suffixunsigned-suffix_opt

unsigned-suffix：以下项之一
 u U

long-suffix：以下项之一
 l L

long-long-suffix：以下项之一
 ll LL

floating-constant:
 decimal-floating-constant
 hexadecimal-floating-constant

decimal-floating-constant:
 fractional-constantexponent-part_optfloating-suffix_opt
 digit-sequenceexponent-partfloating-suffix_opt

hexadecimal-floating-constant:
 hexadecimal-prefixhexadecimal-fractional-constantbinary-exponent-part_optfloating-suffix_opt
 hexadecimal-prefixhexadecimal-digit-sequencebinary-exponent-partfloating-suffix_opt

fractional-constant:
 digit-sequence_opt.digit-sequence
 digit-sequence .

exponent-part:
 esign_optdigit-sequence
 Esign_optdigit-sequence

sign：以下项之一
 + -

digit-sequence:
 digit
 digit-sequence digit

hexadecimal-fractional-constant:
 hexadecimal-digit-sequence_opt.hexadecimal-digit-sequence
 hexadecimal-digit-sequence .

binary-exponent-part:
 psign_optdigit-sequence
 Psign_optdigit-sequence

hexadecimal-digit-sequence:
 hexadecimal-digit
 hexadecimal-digit-sequence hexadecimal-digit

floating-suffix：以下项之一
 f l F L

enumeration-constant:
 identifier

character-constant:
 ' c-char-sequence '
 L' c-char-sequence '

c-char-sequence:
 c-char
 c-char-sequence c-char

c-char:
 除单引号 (')、反斜杠 (\) 或者换行符以外的所有源字符集成员
 escape-sequence

escape-sequence:
 simple-escape-sequence
 octal-escape-sequence
 hexadecimal-escape-sequence
 universal-character-name

simple-escape-sequence：以下项之一
 \a \b \f \n \r \t \v
 \' \" \\ \?

octal-escape-sequence:
 \ octal-digit
 \ octal-digit octal-digit
 \ octal-digit octal-digit octal-digit

hexadecimal-escape-sequence:
 \x hexadecimal-digit
 hexadecimal-escape-sequence hexadecimal-digit

字符串文本

string-literal:
 encoding-prefix"s-char-sequence_opt"

encoding-prefix:
 u8
 u
 U
 L

s-char-sequence:
 s-char
 s-char-sequence s-char

s-char:
 除双引号 (")、反斜杠 (\) 或者换行符以外的任何源字符集成员
 escape-sequence

标点符号

punctuator：以下项之一
 [ ] ( ) { } . ->
 ++ -- & * + - ~ !
 / % << >> < > <= >= ==
 != ^ | && || ? : ; ...
 = *= /= %= += -= <<= >>=
 &= ^= |= , # ##
 <: :> <% %> %: %:%:

标头名称

header-name:
 < h-char-sequence >
 " q-char-sequence "

h-char-sequence:
 h-char
 h-char-sequence h-char

h-char:
 除换行符和 > 以外的任何源字符集成员

q-char-sequence:
 q-char
 q-char-sequence q-char

q-char:
 除换行符和 " 以外的任何源字符集成员

预处理数字

pp-number:
 digit
 . digit
 pp-number digit
 pp-number identifier-nondigit
 pp-number e sign
 pp-number E sign
 pp-number p sign
 pp-number P sign
 pp-number .

¹binary-constant、binary-prefix 和 binary-digit 是 Microsoft 专用的扩展。

请参阅

C 语言语法摘要