http://blog.chinaunix.net/uid-26588712-id-3068151.html c++ 数据类型
按照posix标准，一般整型对应的*_t类型为：
1字节 uint8_t
2字节 uint16_t
4字节 uint32_t
8字节 uint64_t
/* Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
/*
* ISO C99: 7.18 Integer types <stdint.h>
*/
#ifndef _STDINT_H
#define _STDINT_H 1
#include <features.h>
#include <bits/wchar.h>
#include <bits/wordsize.h>
/* Exact integral types. */
/* Signed. */
/* There is some amount of overlap with <sys/types.h> as known by inet code */
#ifndef __int8_t_defined
# define __int8_t_defined
typedef signed char int8_t;
typedef short int int16_t;
typedef int int32_t;
# if __WORDSIZE == 64
typedef long int int64_t;
# else
__extension__
typedef long long int int64_t;
# endif
#endif
/* Unsigned. */
typedef unsigned char uint8_t;
typedef unsigned short int uint16_t;
#ifndef __uint32_t_defined
typedef unsigned int uint32_t;
# define __uint32_t_defined
#endif
#if __WORDSIZE == 64
typedef unsigned long int uint64_t;
#else
__extension__
typedef unsigned long long int uint64_t;
#endif
/* Small types. */
/* Signed. */
typedef signed char int_least8_t;
typedef short int int_least16_t;
typedef int int_least32_t;
#if __WORDSIZE == 64
typedef long int int_least64_t;
#else
__extension__
typedef long long int int_least64_t;
#endif
/* Unsigned. */
typedef unsigned char uint_least8_t;
typedef unsigned short int uint_least16_t;
typedef unsigned int uint_least32_t;
#if __WORDSIZE == 64
typedef unsigned long int uint_least64_t;
#else
__extension__
typedef unsigned long long int uint_least64_t;
#endif
/* Fast types. */
/* Signed. */
typedef signed char int_fast8_t;
#if __WORDSIZE == 64
typedef long int int_fast16_t;
typedef long int int_fast32_t;
typedef long int int_fast64_t;
#else
typedef int int_fast16_t;
typedef int int_fast32_t;
__extension__
typedef long long int int_fast64_t;
#endif
/* Unsigned. */
typedef unsigned char uint_fast8_t;
#if __WORDSIZE == 64
typedef unsigned long int uint_fast16_t;
typedef unsigned long int uint_fast32_t;
typedef unsigned long int uint_fast64_t;
#else
typedef unsigned int uint_fast16_t;
typedef unsigned int uint_fast32_t;
__extension__
typedef unsigned long long int uint_fast64_t;
#endif
/* Types for `void *' pointers. */
#if __WORDSIZE == 64
# ifndef __intptr_t_defined
typedef long int intptr_t;
# define __intptr_t_defined
# endif
typedef unsigned long int uintptr_t;
#else
# ifndef __intptr_t_defined
typedef int intptr_t;
# define __intptr_t_defined
# endif
typedef unsigned int uintptr_t;
#endif
/* Largest integral types. */
#if __WORDSIZE == 64
typedef long int intmax_t;
typedef unsigned long int uintmax_t;
#else
__extension__
typedef long long int intmax_t;
__extension__
typedef unsigned long long int uintmax_t;
#endif
/* The ISO C99 standard specifies that in C++ implementations these
macros should only be defined if explicitly requested. */
#if !defined __cplusplus || defined __STDC_LIMIT_MACROS
# if __WORDSIZE == 64
# define __INT64_C(c) c ## L
# define __UINT64_C(c) c ## UL
# else
# define __INT64_C(c) c ## LL
# define __UINT64_C(c) c ## ULL
# endif
/* Limits of integral types. */
/* Minimum of signed integral types. */
# define INT8_MIN (-128)
# define INT16_MIN (-32767-1)
# define INT32_MIN (-2147483647-1)
# define INT64_MIN (-__INT64_C(9223372036854775807)-1)
/* Maximum of signed integral types. */
# define INT8_MAX (127)
# define INT16_MAX (32767)
# define INT32_MAX (2147483647)
# define INT64_MAX (__INT64_C(9223372036854775807))
/* Maximum of unsigned integral types. */
# define UINT8_MAX (255)
# define UINT16_MAX (65535)
# define UINT32_MAX (4294967295U)
# define UINT64_MAX (__UINT64_C(18446744073709551615))
/* Minimum of signed integral types having a minimum size. */
# define INT_LEAST8_MIN (-128)
# define INT_LEAST16_MIN (-32767-1)
# define INT_LEAST32_MIN (-2147483647-1)
# define INT_LEAST64_MIN (-__INT64_C(9223372036854775807)-1)
/* Maximum of signed integral types having a minimum size. */
# define INT_LEAST8_MAX (127)
# define INT_LEAST16_MAX (32767)
# define INT_LEAST32_MAX (2147483647)
# define INT_LEAST64_MAX (__INT64_C(9223372036854775807))
/* Maximum of unsigned integral types having a minimum size. */
# define UINT_LEAST8_MAX (255)
# define UINT_LEAST16_MAX (65535)
# define UINT_LEAST32_MAX (4294967295U)
# define UINT_LEAST64_MAX (__UINT64_C(18446744073709551615))
/* Minimum of fast signed integral types having a minimum size. */
# define INT_FAST8_MIN (-128)
# if __WORDSIZE == 64
# define INT_FAST16_MIN (-9223372036854775807L-1)
# define INT_FAST32_MIN (-9223372036854775807L-1)
# else
# define INT_FAST16_MIN (-2147483647-1)
# define INT_FAST32_MIN (-2147483647-1)
# endif
# define INT_FAST64_MIN (-__INT64_C(9223372036854775807)-1)
/* Maximum of fast signed integral types having a minimum size. */
# define INT_FAST8_MAX (127)
# if __WORDSIZE == 64
# define INT_FAST16_MAX (9223372036854775807L)
# define INT_FAST32_MAX (9223372036854775807L)
# else
# define INT_FAST16_MAX (2147483647)
# define INT_FAST32_MAX (2147483647)
# endif
# define INT_FAST64_MAX (__INT64_C(9223372036854775807))
/* Maximum of fast unsigned integral types having a minimum size. */
# define UINT_FAST8_MAX (255)
# if __WORDSIZE == 64
# define UINT_FAST16_MAX (18446744073709551615UL)
# define UINT_FAST32_MAX (18446744073709551615UL)
# else
# define UINT_FAST16_MAX (4294967295U)
# define UINT_FAST32_MAX (4294967295U)
# endif
# define UINT_FAST64_MAX (__UINT64_C(18446744073709551615))
/* Values to test for integral types holding `void *' pointer. */
# if __WORDSIZE == 64
# define INTPTR_MIN (-9223372036854775807L-1)
# define INTPTR_MAX (9223372036854775807L)
# define UINTPTR_MAX (18446744073709551615UL)
# else
# define INTPTR_MIN (-2147483647-1)
# define INTPTR_MAX (2147483647)
# define UINTPTR_MAX (4294967295U)
# endif
/* Minimum for largest signed integral type. */
# define INTMAX_MIN (-__INT64_C(9223372036854775807)-1)
/* Maximum for largest signed integral type. */
# define INTMAX_MAX (__INT64_C(9223372036854775807))
/* Maximum for largest unsigned integral type. */
# define UINTMAX_MAX (__UINT64_C(18446744073709551615))
/* Limits of other integer types. */
/* Limits of `ptrdiff_t' type. */
# if __WORDSIZE == 64
# define PTRDIFF_MIN (-9223372036854775807L-1)
# define PTRDIFF_MAX (9223372036854775807L)
# else
# define PTRDIFF_MIN (-2147483647-1)
# define PTRDIFF_MAX (2147483647)
# endif
/* Limits of `sig_atomic_t'. */
# define SIG_ATOMIC_MIN (-2147483647-1)
# define SIG_ATOMIC_MAX (2147483647)
/* Limit of `size_t' type. */
# if __WORDSIZE == 64
# define SIZE_MAX (18446744073709551615UL)
# else
# define SIZE_MAX (4294967295U)
# endif
/* Limits of `wchar_t'. */
# ifndef WCHAR_MIN
/* These constants might also be defined in <wchar.h>. */
# define WCHAR_MIN __WCHAR_MIN
# define WCHAR_MAX __WCHAR_MAX
# endif
/* Limits of `wint_t'. */
# define WINT_MIN (0u)
# define WINT_MAX (4294967295u)
#endif /* C++ && limit macros */
/* The ISO C99 standard specifies that in C++ implementations these
should only be defined if explicitly requested. */
#if !defined __cplusplus || defined __STDC_CONSTANT_MACROS
/* Signed. */
# define INT8_C(c) c
# define INT16_C(c) c
# define INT32_C(c) c
# if __WORDSIZE == 64
# define INT64_C(c) c ## L
# else
# define INT64_C(c) c ## LL
# endif
/* Unsigned. */
# define UINT8_C(c) c ## U
# define UINT16_C(c) c ## U
# define UINT32_C(c) c ## U
# if __WORDSIZE == 64
# define UINT64_C(c) c ## UL
# else
# define UINT64_C(c) c ## ULL
# endif
/* Maximal type. */
# if __WORDSIZE == 64
# define INTMAX_C(c) c ## L
# define UINTMAX_C(c) c ## UL
# else
# define INTMAX_C(c) c ## LL
# define UINTMAX_C(c) c ## ULL
# endif
#endif /* C++ && constant macros */
#endif /* stdint.h */
1字节 uint8_t
2字节 uint16_t
4字节 uint32_t
8字节 uint64_t