库标准整数类型详细设计

Exact-width integer types

Integer types having exactly the specified width

typedef signed char int8_t

typedef unsigned char uint8_t

typedef signed int int16_t

typedef unsigned int uint16_t

typedef signed long int int32_t

typedef unsigned long int uint32_t

typedef signed long long int int64_t

typedef unsigned long long int uint64_t

Integer types capable of holding object pointers

These allow you to declare variables of the same size as a pointer.

typedef int16_t intptr_t

typedef uint16_t uintptr_t

Minimum-width integer types

Integer types having at least the specified width

typedef int8_t int_least8_t

typedef uint8_t uint_least8_t

typedef int16_t int_least16_t

typedef uint16_t uint_least16_t

typedef int32_t int_least32_t

typedef uint32_t uint_least32_t

typedef int64_t int_least64_t

typedef uint64_t uint_least64_t

Fastest minimum-width integer types

Integer types being usually fastest having at least the specified width

typedef int8_t int_fast8_t

typedef uint8_t uint_fast8_t

typedef int16_t int_fast16_t

typedef uint16_t uint_fast16_t

typedef int32_t int_fast32_t

typedef uint32_t uint_fast32_t

typedef int64_t int_fast64_t

typedef uint64_t uint_fast64_t

Greatest-width integer types

Types designating integer data capable of representing any value of any integer type in the corresponding signed or unsigned category

typedef int64_t intmax_t

typedef uint64_t uintmax_t

Limits of specified-width integer types

C++ implementations should define these macros only when __STDC_LIMIT_MACROS is defined before < stdint.h> is included

#define INT8_MAX 0x7f

#define INT8_MIN (-INT8_MAX - 1)

#define UINT8_MAX (__CONCAT(INT8_MAX, U) * 2U + 1U)

#define INT16_MAX 0x7fff

#define INT16_MIN (-INT16_MAX - 1)

#define UINT16_MAX (__CONCAT(INT16_MAX, U) * 2U + 1U)

#define INT32_MAX 0x7fffffffL

#define INT32_MIN (-INT32_MAX - 1L)

#define UINT32_MAX (__CONCAT(INT32_MAX, U) * 2UL + 1UL)

#define INT64_MAX 0x7fffffffffffffffLL

#define INT64_MIN (-INT64_MAX - 1LL)

#define UINT64_MAX (__CONCAT(INT64_MAX, U) * 2ULL + 1ULL)

Limits of minimum-width integer types

#define INT_LEAST8_MAX INT8_MAX

#define INT_LEAST8_MIN INT8_MIN

#define UINT_LEAST8_MAX UINT8_MAX

#define INT_LEAST16_MAX INT16_MAX

#define INT_LEAST16_MIN INT16_MIN

#define UINT_LEAST16_MAX UINT16_MAX

#define INT_LEAST32_MAX INT32_MAX

#define INT_LEAST32_MIN INT32_MIN

#define UINT_LEAST32_MAX UINT32_MAX

#define INT_LEAST64_MAX INT64_MAX

#define INT_LEAST64_MIN INT64_MIN

#define UINT_LEAST64_MAX UINT64_MAX

Limits of fastest minimum-width integer types

#define INT_FAST8_MAX INT8_MAX

#define INT_FAST8_MIN INT8_MIN

#define UINT_FAST8_MAX UINT8_MAX

#define INT_FAST16_MAX INT16_MAX

#define INT_FAST16_MIN INT16_MIN

#define UINT_FAST16_MAX UINT16_MAX

#define INT_FAST32_MAX INT32_MAX

#define INT_FAST32_MIN INT32_MIN

#define UINT_FAST32_MAX UINT32_MAX

#define INT_FAST64_MAX INT64_MAX

#define INT_FAST64_MIN INT64_MIN

#define UINT_FAST64_MAX UINT64_MAX

Limits of integer types capable of holding object pointers

#define INTPTR_MAX INT16_MAX

#define INTPTR_MIN INT16_MIN

#define UINTPTR_MAX UINT16_MAX

Limits of greatest-width integer types

#define INTMAX_MAX INT64_MAX

#define INTMAX_MIN INT64_MIN

#define UINTMAX_MAX UINT64_MAX

Limits of other integer types

C++ implementations should define these macros only when __STDC_LIMIT_MACROS is defined before < stdint.h> is included

#define PTRDIFF_MAX INT16_MAX

#define PTRDIFF_MIN INT16_MIN

#define SIG_ATOMIC_MAX INT8_MAX

#define SIG_ATOMIC_MIN INT8_MIN

#define SIZE_MAX (__CONCAT(INT16_MAX, U))

Macros for integer constants

C++ implementations should define these macros only when __STDC_CONSTANT_MACROS is defined before < stdint.h> is included.

These definitions are valid for integer constants without suffix and for macros defined as integer constant without suffix

#define INT8_C(value) (( int8_t) value)

#define UINT8_C(value) (( uint8_t) __CONCAT(value, U))

#define INT16_C(value) value

#define UINT16_C(value) __CONCAT(value, U)

#define INT32_C(value) __CONCAT(value, L)

#define UINT32_C(value) __CONCAT(value, UL)

#define INT64_C(value) __CONCAT(value, LL)

#define UINT64_C(value) __CONCAT(value, ULL)

#define INTMAX_C(value) __CONCAT(value, LL)

#define UINTMAX_C(value) __CONCAT(value, ULL)

Define Documentation

#define INT16_C(value) value

define a constant of type int16_t

#define INT16_MAX 0x7fff

largest positive value an int16_t can hold.

#define INT16_MIN (-INT16_MAX - 1)

smallest negative value an int16_t can hold.

#define INT32_C(value) __CONCAT(value, L)

define a constant of type int32_t

#define INT32_MAX 0x7fffffffL

largest positive value an int32_t can hold.

#define INT32_MIN (-INT32_MAX - 1L)

smallest negative value an int32_t can hold.

#define INT64_C(value) __CONCAT(value, LL)

define a constant of type int64_t

#define INT64_MAX 0x7fffffffffffffffLL

largest positive value an int64_t can hold.

#define INT64_MIN (-INT64_MAX - 1LL)

smallest negative value an int64_t can hold.

#define INT8_C(value) ((int8_t) value)

define a constant of type int8_t

#define INT8_MAX 0x7f

largest positive value an int8_t can hold.

#define INT8_MIN (-INT8_MAX - 1)

smallest negative value an int8_t can hold.

#define INT_FAST16_MAX INT16_MAX

largest positive value an int_fast16_t can hold.

#define INT_FAST16_MIN INT16_MIN

smallest negative value an int_fast16_t can hold.

#define INT_FAST32_MAX INT32_MAX

largest positive value an int_fast32_t can hold.

#define INT_FAST32_MIN INT32_MIN

smallest negative value an int_fast32_t can hold.

#define INT_FAST64_MAX INT64_MAX

largest positive value an int_fast64_t can hold.

#define INT_FAST64_MIN INT64_MIN

smallest negative value an int_fast64_t can hold.

#define INT_FAST8_MAX INT8_MAX

largest positive value an int_fast8_t can hold.

#define INT_FAST8_MIN INT8_MIN

smallest negative value an int_fast8_t can hold.

#define INT_LEAST16_MAX INT16_MAX

largest positive value an int_least16_t can hold.

#define INT_LEAST16_MIN INT16_MIN

smallest negative value an int_least16_t can hold.

#define INT_LEAST32_MAX INT32_MAX

largest positive value an int_least32_t can hold.

#define INT_LEAST32_MIN INT32_MIN

smallest negative value an int_least32_t can hold.

#define INT_LEAST64_MAX INT64_MAX

largest positive value an int_least64_t can hold.

#define INT_LEAST64_MIN INT64_MIN

smallest negative value an int_least64_t can hold.

#define INT_LEAST8_MAX INT8_MAX

largest positive value an int_least8_t can hold.

#define INT_LEAST8_MIN INT8_MIN

smallest negative value an int_least8_t can hold.

#define INTMAX_C(value) __CONCAT(value, LL)

define a constant of type intmax_t

#define INTMAX_MAX INT64_MAX

largest positive value an intmax_t can hold.

#define INTMAX_MIN INT64_MIN

smallest negative value an intmax_t can hold.

#define INTPTR_MAX INT16_MAX

largest positive value an intptr_t can hold.

#define INTPTR_MIN INT16_MIN

smallest negative value an intptr_t can hold.

#define PTRDIFF_MAX INT16_MAX

largest positive value a ptrdiff_t can hold.

#define PTRDIFF_MIN INT16_MIN

smallest negative value a ptrdiff_t can hold.

#define SIG_ATOMIC_MAX INT8_MAX

largest positive value a sig_atomic_t can hold.

#define SIG_ATOMIC_MIN INT8_MIN

smallest negative value a sig_atomic_t can hold.

#define SIZE_MAX (__CONCAT(INT16_MAX, U))

largest value a size_t can hold.

#define UINT16_C(value) __CONCAT(value, U)

define a constant of type uint16_t

#define UINT16_MAX (__CONCAT(INT16_MAX, U) * 2U + 1U)

largest value an uint16_t can hold.

#define UINT32_C(value) __CONCAT(value, UL)

define a constant of type uint32_t

#define UINT32_MAX (__CONCAT(INT32_MAX, U) * 2UL + 1UL)

largest value an uint32_t can hold.

#define UINT64_C(value) __CONCAT(value, ULL)

define a constant of type uint64_t

#define UINT64_MAX (__CONCAT(INT64_MAX, U) * 2ULL + 1ULL)

largest value an uint64_t can hold.

#define UINT8_C(value) ((uint8_t) __CONCAT(value, U))

define a constant of type uint8_t

#define UINT8_MAX (__CONCAT(INT8_MAX, U) * 2U + 1U)

largest value an uint8_t can hold.

#define UINT_FAST16_MAX UINT16_MAX

largest value an uint_fast16_t can hold.

#define UINT_FAST32_MAX UINT32_MAX

largest value an uint_fast32_t can hold.

#define UINT_FAST64_MAX UINT64_MAX

largest value an uint_fast64_t can hold.

#define UINT_FAST8_MAX UINT8_MAX

largest value an uint_fast8_t can hold.

#define UINT_LEAST16_MAX UINT16_MAX

largest value an uint_least16_t can hold.

#define UINT_LEAST32_MAX UINT32_MAX

largest value an uint_least32_t can hold.

#define UINT_LEAST64_MAX UINT64_MAX

largest value an uint_least64_t can hold.

#define UINT_LEAST8_MAX UINT8_MAX

largest value an uint_least8_t can hold.

#define UINTMAX_C(value) __CONCAT(value, ULL)

define a constant of type uintmax_t

#define UINTMAX_MAX UINT64_MAX

largest value an uintmax_t can hold.

#define UINTPTR_MAX UINT16_MAX

largest value an uintptr_t can hold.

Typedef Documentation

typedef signed int int16_t

16-bit signed type.

typedef signed long int int32_t

32-bit signed type.

typedef signed long long int int64_t

64-bit signed type.

Note:

This type is not available when the compiler option -mint8 is in effect.

typedef signed char int8_t

8-bit signed type.

typedef int16_t int_fast16_t

fastest signed int with at least 16 bits.

typedef int32_t int_fast32_t

fastest signed int with at least 32 bits.

typedef int64_t int_fast64_t

fastest signed int with at least 64 bits.

Note:

This type is not available when the compiler option -mint8 is in effect.

typedef int8_t int_fast8_t

fastest signed int with at least 8 bits.

typedef int16_t int_least16_t

signed int with at least 16 bits.

typedef int32_t int_least32_t

signed int with at least 32 bits.

typedef int64_t int_least64_t

signed int with at least 64 bits.

Note:

This type is not available when the compiler option -mint8 is in effect.

typedef int8_t int_least8_t

signed int with at least 8 bits.

typedef int64_t intmax_t

largest signed int available.

typedef int16_t intptr_t

Signed pointer compatible type.

typedef unsigned int uint16_t

16-bit unsigned type.

typedef unsigned long int uint32_t

32-bit unsigned type.

typedef unsigned long long int uint64_t

64-bit unsigned type.

Note:

This type is not available when the compiler option -mint8 is in effect.

typedef unsigned char uint8_t

8-bit unsigned type.

typedef uint16_t uint_fast16_t

fastest unsigned int with at least 16 bits.

typedef uint32_t uint_fast32_t

fastest unsigned int with at least 32 bits.

typedef uint64_t uint_fast64_t

fastest unsigned int with at least 64 bits.

Note:

This type is not available when the compiler option -mint8 is in effect.

typedef uint8_t uint_fast8_t

fastest unsigned int with at least 8 bits.

typedef uint16_t uint_least16_t

unsigned int with at least 16 bits.

typedef uint32_t uint_least32_t

unsigned int with at least 32 bits.

typedef uint64_t uint_least64_t

unsigned int with at least 64 bits.

Note:

This type is not available when the compiler option -mint8 is in effect.

typedef uint8_t uint_least8_t

unsigned int with at least 8 bits.

typedef uint64_t uintmax_t

largest unsigned int available.

typedef uint16_t uintptr_t

Unsigned pointer compatible type.

===========================================================
ssize_t是signed size_t，
而 size_t是标准C库中定义的，应为unsigned int。
socket_t:
数据类型"socklen_t"和int应该具有相同的长度.否则就会破坏 BSD套接字层的填充.POSIX开始的时候用的是size_t, Linus Torvalds(他希望有更多的人,但显然不是很多) 努力向他们解释使用size_t是完全错误的,因为在64位结构中 size_t和int的长度是不一样的,而这个参数(也就是accept函数 的第三参数)的长度必须和int一致,因为这是BSD套接字接口 标准.最终POSIX的那帮家伙找到了解决的办法,那就是创造了 一个新的类型"socklen_t".Linux Torvalds说这是由于他们 发现了自己的错误但又不好意思向大家伙儿承认,所以另外 创造了一个新的数据类型.