limits.h头文件的作用

limits.h专门用于检测整型数据数据类型的表达值范围。

附源码:

/****limits.h - implementation dependent values**       Copyright (c) Microsoft Corporation.  All rights reserved.**Purpose:*       Contains defines for a number of implementation dependent values*       which are commonly used in C programs.*       [ANSI]**       [Public]*****/#pragma once#include <crtdefs.h>#ifndef _INC_LIMITS#define _INC_LIMITS#define CHAR_BIT      8         /* number of bits in a char */#define SCHAR_MIN   (-128)      /* minimum signed char value */#define SCHAR_MAX     127       /* maximum signed char value */#define UCHAR_MAX     0xff      /* maximum unsigned char value */#ifndef _CHAR_UNSIGNED#define CHAR_MIN    SCHAR_MIN   /* mimimum char value */#define CHAR_MAX    SCHAR_MAX   /* maximum char value */#else  /* _CHAR_UNSIGNED */#define CHAR_MIN      0#define CHAR_MAX    UCHAR_MAX#endif  /* _CHAR_UNSIGNED */#define MB_LEN_MAX    5             /* max. # bytes in multibyte char */#define SHRT_MIN    (-32768)        /* minimum (signed) short value */#define SHRT_MAX      32767         /* maximum (signed) short value */#define USHRT_MAX     0xffff        /* maximum unsigned short value */#define INT_MIN     (-2147483647 - 1) /* minimum (signed) int value */#define INT_MAX       2147483647    /* maximum (signed) int value */#define UINT_MAX      0xffffffff    /* maximum unsigned int value */#define LONG_MIN    (-2147483647L - 1) /* minimum (signed) long value */#define LONG_MAX      2147483647L   /* maximum (signed) long value */#define ULONG_MAX     0xffffffffUL  /* maximum unsigned long value */#define LLONG_MAX     9223372036854775807i64       /* maximum signed long long int value */#define LLONG_MIN   (-9223372036854775807i64 - 1)  /* minimum signed long long int value */#define ULLONG_MAX    0xffffffffffffffffui64       /* maximum unsigned long long int value */#define _I8_MIN     (-127i8 - 1)    /* minimum signed 8 bit value */#define _I8_MAX       127i8         /* maximum signed 8 bit value */#define _UI8_MAX      0xffui8       /* maximum unsigned 8 bit value */#define _I16_MIN    (-32767i16 - 1) /* minimum signed 16 bit value */#define _I16_MAX      32767i16      /* maximum signed 16 bit value */#define _UI16_MAX     0xffffui16    /* maximum unsigned 16 bit value */#define _I32_MIN    (-2147483647i32 - 1) /* minimum signed 32 bit value */#define _I32_MAX      2147483647i32 /* maximum signed 32 bit value */#define _UI32_MAX     0xffffffffui32 /* maximum unsigned 32 bit value *//* minimum signed 64 bit value */#define _I64_MIN    (-9223372036854775807i64 - 1)/* maximum signed 64 bit value */#define _I64_MAX      9223372036854775807i64/* maximum unsigned 64 bit value */#define _UI64_MAX     0xffffffffffffffffui64#if _INTEGRAL_MAX_BITS >= 128/* minimum signed 128 bit value */#define _I128_MIN   (-170141183460469231731687303715884105727i128 - 1)/* maximum signed 128 bit value */#define _I128_MAX     170141183460469231731687303715884105727i128/* maximum unsigned 128 bit value */#define _UI128_MAX    0xffffffffffffffffffffffffffffffffui128#endif  /* _INTEGRAL_MAX_BITS >= 128 */#ifndef SIZE_MAX#ifdef _WIN64#define SIZE_MAX _UI64_MAX#else  /* _WIN64 */#define SIZE_MAX UINT_MAX#endif  /* _WIN64 */#endif  /* SIZE_MAX */#if __STDC_WANT_SECURE_LIB__#ifndef RSIZE_MAX#define RSIZE_MAX    (SIZE_MAX >> 1)#endif  /* RSIZE_MAX */#endif  /* __STDC_WANT_SECURE_LIB__ */#endif  /* _INC_LIMITS */