简单的C数据类型 [英] Simple C data types

问题描述

可能重复：结果
  <一href=\"http://stackoverflow.com/questions/5254051/the-difference-of-int8-t-int-least8-t-and-int-fast8-t\">The中int8_t，int_least8_t的差异和int_fast8_t？

我是一个很困惑。我想......（纠正我，如果我错了）

I'm a quite confused. I think... (correct me if I'm wrong)

u_int8_t = unsigned short ?
u_int16_t = unsigned int ?
u_int32_t = unsigned long ?
u_int64_t = unsigned long long ?

int8_t = short ?
int16_t = int ?
int32_t = long ?
int64_t = long long ?

那么，什么是 int_fast8_t 是什么意思？ int_fastN_t ？ int_least8_t ？

推荐答案

我写字的地方int是16位的：

I writing where int is of 16-bit:

u_int8_t = unsigned char  
u_int16_t = unsigned int
u_int32_t = unsigned long int
u_int64_t = unsigned long long int 

int8_t =  char
int16_t = int 
int32_t = long int
int64_t = long long int   

---

问：？？？那么，什么是int_fast8_t意味着int_fastN_t int_least8_t

---

Q: "Then what does int_fast8_t mean? int_fastN_t? int_least8_t?"

作为<一dan04状态href=\"http://stackoverflow.com/questions/5254051/the-difference-of-int8-t-int-least8-t-and-int-fast8-t/5254321#5254321\">his回答这里：

假设你有一个36位系统中的C编译器，以字符 = 9
  位，短 = 18位， INT = 36位，而长 = 72位。然后

Suppose you have a C compiler for a 36-bit system, with char = 9 bits, short = 18 bits, int = 36 bits, and long = 72 bits. Then

  
• 中int8_t 的不存在的，因为没有办法满足其的究竟的8值位的约束没有填充。

  
• int_least8_t 是字符的一个typedef。不是的短或 INT ，因为标准要求的最小的类型至少有8个
    位。

  
• int_fast8_t 可以是任何东西。这很可能是 INT 的一个typedef如果本地大小被认为是快。

  

• int8_t does not exist, because there is no way to satisfy the constraint of having exactly 8 value bits with no padding.
• int_least8_t is a typedef of char. NOT of short or int, because the standard requires the smallest type with at least 8 bits.
• int_fast8_t can be anything. It's likely to be a typedef of int if the "native" size is considered to be "fast".

如果您在的Linux 大部分在 /usr/include/linux/coda.h 定义。例如

---

If you are in Linux most these are defined in /usr/include/linux/coda.h. e.g.

#ifndef __BIT_TYPES_DEFINED__
#define __BIT_TYPES_DEFINED__
typedef signed char       int8_t;
typedef unsigned char       u_int8_t;
typedef short            int16_t;
typedef unsigned short     u_int16_t;
typedef int          int32_t;
typedef unsigned int       u_int32_t;
#endif  

和

#if defined(DJGPP) || defined(__CYGWIN32__)
#ifdef KERNEL
typedef unsigned long u_long;
typedef unsigned int u_int;
typedef unsigned short u_short;
typedef u_long ino_t;
typedef u_long dev_t;
typedef void * caddr_t;
#ifdef DOS
typedef unsigned __int64 u_quad_t;
#else 
typedef unsigned long long u_quad_t;
#endif

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