(1)

int scanf（const char * format，...）;

（直到C99）

int scanf（const char * restrict format，...）;

（自C99以来）

(2)

int fscanf（FILE * stream，const char * format，...）;

（直到C99）

int fscanf（FILE * restrict stream，const char * restrict format，...）;

（自C99以来）

(3)

int sscanf（const char * buffer，const char * format，...）;

（直到C99）

int sscanf（const char *限制缓冲区，const char *限制格式，...）;

（自C99以来）

int scanf_s（const char * restrict format，...）;

(4)

（自C11以来）

int fscanf_s（FILE * restrict stream，const char * restrict format，...）;

(5)

（自C11以来）

int sscanf_s（const char *限制缓冲区，const char *限制格式，...）;

(6)

（自C11以来）

缓冲

-

指向以null结尾的字符串读取的指针

格式

-

pointer to a null-terminated character string specifying how to read the input. The format string consists of. non-whitespace multibyte characters except %: each such character in the format string consumes exactly one identical character from the input stream, or causes the function to fail if the next character on the stream does not compare equal. whitespace characters: any single whitespace character in the format string consumes all available consecutive whitespace characters from the input (determined as if by calling isspace in a loop). Note that there is no difference between "\n", " ", "\t\t", or other whitespace in the format string. conversion specifications. Each conversion specification has the following format: introductory % character (optional) assignment-suppressing character *. If this option is present, the function does not assign the result of the conversion to any receiving argument. (optional) integer number (greater than zero) that specifies maximum field width, that is, the maximum number of characters that the function is allowed to consume when doing the conversion specified by the current conversion specification. Note that %s and %[ may lead to buffer overflow if the width is not provided. (optional) length modifier that specifies the size of the receiving argument, that is, the actual destination type. This affects the conversion accuracy and overflow rules. The default destination type is different for each conversion type (see table below). conversion format specifier The following format specifiers are available: Conversion specifier Explanation Argument type length modifier hh (C99). h (none) l ll (C99). j (C99). z (C99). t (C99). L % matches literal % N/A N/A N/A N/A N/A N/A N/A N/A N/A c matches a character or a sequence of characters If a width specifier is used, matches exactly width characters (the argument must be a pointer to an array with sufficient room). Unlike %s and %[, does not append the null character to the array. N/A N/A char* wchar_t* N/A N/A N/A N/A N/A s matches a sequence of non-whitespace characters (a string) If width specifier is used, matches up to width or until the first whitespace character, whichever appears first. Always stores a null character in addition to the characters matched (so the argument array must have room for at least width+1 characters). set matches a non-empty sequence of character from set of characters. If the first character of the set is ^, then all characters not in the set are matched. If the set begins with ] or ^] then the ] character is also included into the set. It is implementation-defined whether the character - in the non-initial position in the scanset may be indicating a range, as in 0-9. If width specifier is used, matches only up to width. Always stores a null character in addition to the characters matched (so the argument array must have room for at least width+1 characters). d matches a decimal integer. The format of the number is the same as expected by strtol() with the value 10 for the base argument. signed char* or unsigned char* signed short* or unsigned short* signed int* or unsigned int* signed long* or unsigned long* signed long long* or unsigned long long* intmax_t* or uintmax_t* size_t* ptrdiff_t* N/A i matches an integer. The format of the number is the same as expected by strtol() with the value 0 for the base argument (base is determined by the first characters parsed). u matches an unsigned decimal integer. The format of the number is the same as expected by strtoul() with the value 10 for the base argument. o matches an unsigned octal integer. The format of the number is the same as expected by strtoul() with the value 8 for the base argument. x, X matches an unsigned hexadecimal integer. The format of the number is the same as expected by strtoul() with the value 16 for the base argument. n returns the number of characters read so far. No input is consumed. Does not increment the assignment count. If the specifier has assignment-suppressing operator defined, the behavior is undefined. a, A(C99) e, E f, F g, G matches a floating-point number. The format of the number is the same as expected by strtof(). N/A N/A float* double* N/A N/A N/A N/A long double* p matches implementation defined character sequence defining a pointer. printf family of functions should produce the same sequence using %p format specifier. N/A N/A void** N/A N/A N/A N/A N/A N/A For every conversion specifier other than n, the longest sequence of input characters which does not exceed any specified field width and which either is exactly what the conversion specifier expects or is a prefix of a sequence it would expect, is what's consumed from the stream. The first character, if any, after this consumed sequence remains unread. If the consumed sequence has length zero or if the consumed sequence cannot be converted as specified above, the matching failure occurs unless end-of-file, an encoding error, or a read error prevented input from the stream, in which case it is an input failure. All conversion specifiers other than [, c, and n consume and discard all leading whitespace characters (determined as if by calling isspace) before attempting to parse the input. These consumed characters do not count towards the specified maximum field width. The conversion specifiers lc, ls, and l[ perform multibyte-to-wide character conversion as if by calling mbrtowc() with an mbstate_t object initialized to zero before the first character is converted. The conversion specifiers s and [ always store the null terminator in addition to the matched characters. The size of the destination array must be at least one greater than the specified field width. The use of %s or %[, without specifying the destination array size, is as unsafe as gets. The correct conversion specifications for the fixed-width integer types (int8_t, etc) are defined in the header (although SCNdMAX, SCNuMAX, etc is synonymous with %jd, %ju, etc). There is a sequence point after the action of each conversion specifier; this permits storing multiple fields in the same "sink" variable. When parsing an incomplete floating-point value that ends in the exponent with no digits, such as parsing "100er" with the conversion specifier %f, the sequence "100e" (the longest prefix of a possibly valid floating-point number) is consumed, resulting in a matching error (the consumed sequence cannot be converted to a floating-point number), with "r" remaining. Existing implementations do not follow this rule and roll back to consume only "100", leaving "er", e.g. glibc bug 1765.

Conversion specifier

Explanation

Argument type

length modifier

hh (C99).

h

(none)

l

ll (C99).

j (C99).

z (C99).

t (C99).

L

%

matches literal %

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

c

matches a character or a sequence of characters If a width specifier is used, matches exactly width characters (the argument must be a pointer to an array with sufficient room). Unlike %s and %[, does not append the null character to the array.

N/A

N/A

char*

wchar_t*

N/A

N/A

N/A

N/A

N/A

s

matches a sequence of non-whitespace characters (a string) If width specifier is used, matches up to width or until the first whitespace character, whichever appears first. Always stores a null character in addition to the characters matched (so the argument array must have room for at least width+1 characters).

set

matches a non-empty sequence of character from set of characters. If the first character of the set is ^, then all characters not in the set are matched. If the set begins with ] or ^] then the ] character is also included into the set. It is implementation-defined whether the character - in the non-initial position in the scanset may be indicating a range, as in 0-9. If width specifier is used, matches only up to width. Always stores a null character in addition to the characters matched (so the argument array must have room for at least width+1 characters).

d

matches a decimal integer. The format of the number is the same as expected by strtol() with the value 10 for the base argument.

signed char* or unsigned char*

signed short* or unsigned short*

signed int* or unsigned int*

signed long* or unsigned long*

signed long long* or unsigned long long*

intmax_t* or uintmax_t*

size_t*

ptrdiff_t*

N/A

i

matches an integer. The format of the number is the same as expected by strtol() with the value 0 for the base argument (base is determined by the first characters parsed).

u

matches an unsigned decimal integer. The format of the number is the same as expected by strtoul() with the value 10 for the base argument.

o

matches an unsigned octal integer. The format of the number is the same as expected by strtoul() with the value 8 for the base argument.

x, X

matches an unsigned hexadecimal integer. The format of the number is the same as expected by strtoul() with the value 16 for the base argument.

n

returns the number of characters read so far. No input is consumed. Does not increment the assignment count. If the specifier has assignment-suppressing operator defined, the behavior is undefined.

a, A(C99) e, E f, F g, G

matches a floating-point number. The format of the number is the same as expected by strtof().

N/A

N/A

float*

double*

N/A

N/A

N/A

N/A

long double*

p

matches implementation defined character sequence defining a pointer. printf family of functions should produce the same sequence using %p format specifier.

N/A

N/A

void**

N/A

N/A

N/A

N/A

N/A

N/A

Conversion specifier

Explanation

Argument type

length modifier

hh (C99).

h

(none)

l

ll (C99).

j (C99).

z (C99).

t (C99).

L

%

matches literal %

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

c

matches a character or a sequence of characters If a width specifier is used, matches exactly width characters (the argument must be a pointer to an array with sufficient room). Unlike %s and %[, does not append the null character to the array.

N/A

N/A

char*

wchar_t*

N/A

N/A

N/A

N/A

N/A

s

matches a sequence of non-whitespace characters (a string) If width specifier is used, matches up to width or until the first whitespace character, whichever appears first. Always stores a null character in addition to the characters matched (so the argument array must have room for at least width+1 characters).

set

matches a non-empty sequence of character from set of characters. If the first character of the set is ^, then all characters not in the set are matched. If the set begins with ] or ^] then the ] character is also included into the set. It is implementation-defined whether the character - in the non-initial position in the scanset may be indicating a range, as in 0-9. If width specifier is used, matches only up to width. Always stores a null character in addition to the characters matched (so the argument array must have room for at least width+1 characters).

d

matches a decimal integer. The format of the number is the same as expected by strtol() with the value 10 for the base argument.

signed char* or unsigned char*

signed short* or unsigned short*

signed int* or unsigned int*

signed long* or unsigned long*

signed long long* or unsigned long long*

intmax_t *或uintmax_t *

为size_t *

ptrdiff_t的*

N / A

一世

匹配一个整数。数字的格式与strtol（）所期望的相同，基本参数的值为0（基数由解析的第一个字符决定）。

在

匹配一个无符号的十进制整数。数字的格式与strtoul（）的预期相同，基本参数的值为10。

该

匹配一个无符号的八进制整数。数字的格式与strtoul（）的预期相同，基本参数的值为8。

x，X

匹配一个无符号的十六进制整数。数字的格式与strtoul（）预期的基本参数的值为16相同。

ñ

返回迄今阅读的字符数。没有输入被消耗。不增加分配计数。如果说明符具有定义的分配抑制运算符，则行为是未定义的。

a，A（C99）e，E f，F g，G

匹配一个浮点数。数字的格式与strtof（）的预期相同。

N / A

N / A

浮动*

双*

N / A

N / A

N / A

N / A

长双*

p

匹配定义指针的实现定义的字符序列。printf系列函数应该使用％p格式说明符产生相同的序列。

N / A

N / A

无效**

N / A

N / A

N / A

N / A

N / A

N / A

...

-

接收参数