C++中的limits.h和climits（C++基本数据类型的最值）

本文主要是介绍C++中的limits.h和climits（C++基本数据类型的最值），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

昨天有同学问到有关C++里具体数值的问题，看到还是有一点点懵的，想想网上应该能找到相关资料吧，后来发现挺少的，其实在mingw（编译文件）里可以找到limits.h这个文件，具体信息如下：

/** limits.h* This file has no copyright assigned and is placed in the Public Domain.* This file is a part of the mingw-runtime package.* No warranty is given; refer to the file DISCLAIMER within the package.** Functions for manipulating paths and directories (included from io.h)* plus functions for setting the current drive.** Defines constants for the sizes of integral types.** NOTE: GCC should supply a version of this header and it should be safe to*       use that version instead of this one (maybe safer).**/#ifndef _LIMITS_H_
#define _LIMITS_H_/* All the headers include this file. */
#include <_mingw.h>/** File system limits** TODO: NAME_MAX and OPEN_MAX are file system limits or not? Are they the*       same as FILENAME_MAX and FOPEN_MAX from stdio.h?* NOTE: PATH_MAX is the POSIX equivalent for Microsoft's MAX_PATH; the two*       are semantically identical, with a limit of 259 characters for the*       path name, plus one for a terminating NUL, for a total of 260.*/
#define PATH_MAX    260/** Characteristics of the char data type.** TODO: Is MB_LEN_MAX correct?*/
#define CHAR_BIT    8
#define MB_LEN_MAX  2#define SCHAR_MIN   (-128)
#define SCHAR_MAX   127#define UCHAR_MAX   255/* TODO: Is this safe? I think it might just be testing the preprocessor,*       not the compiler itself... */
#if ('\x80' < 0)
#define CHAR_MIN    SCHAR_MIN
#define CHAR_MAX    SCHAR_MAX
#else
#define CHAR_MIN    0
#define CHAR_MAX    UCHAR_MAX
#endif/** Maximum and minimum values for ints.*/
#define INT_MAX     2147483647
#define INT_MIN     (-INT_MAX-1)#define UINT_MAX    0xffffffff/** Maximum and minimum values for shorts.*/
#define SHRT_MAX    32767
#define SHRT_MIN    (-SHRT_MAX-1)#define USHRT_MAX   0xffff/** Maximum and minimum values for longs and unsigned longs.** TODO: This is not correct for Alphas, which have 64 bit longs.*/
#define LONG_MAX    2147483647L
#define LONG_MIN    (-LONG_MAX-1)#define ULONG_MAX   0xffffffffUL#ifndef __STRICT_ANSI__
/* POSIX wants this.  */
#define SSIZE_MAX LONG_MAX
#endif#if (defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) \|| !defined(__STRICT_ANSI__)
/* ISO C9x macro names */
#define LLONG_MAX 9223372036854775807LL
#define LLONG_MIN (-LLONG_MAX - 1)
#define ULLONG_MAX (2ULL * LLONG_MAX + 1)
#endif/** The GNU C compiler also allows 'long long int'*/
#if !defined(__STRICT_ANSI__) && defined(__GNUC__)#define LONG_LONG_MAX   9223372036854775807LL
#define LONG_LONG_MIN   (-LONG_LONG_MAX-1)
#define ULONG_LONG_MAX  (2ULL * LONG_LONG_MAX + 1)/* MSVC compatibility */
#define _I64_MIN LONG_LONG_MIN
#define _I64_MAX LONG_LONG_MAX
#define _UI64_MAX ULONG_LONG_MAX#endif /* Not Strict ANSI and GNU C compiler */#endif /* not _LIMITS_H_ */