<climits>头文件定义的符号常量
CHAR_MIN char的最小值
SCHAR_MAX signed char 最大值
SCHAR_MIN signed char 最小值
UCHAR_MAX unsigned char 最大值
SHRT_MAX short 最大值
SHRT_MIN short 最小值
USHRT_MAX unsigned short 最大值
INT_MAX int 最大值
INT_MIN int 最小值
UINT_MAX unsigned int 最大值
UINT_MIN unsigned int 最小值
LONG_MAX long最大值
LONG_MIN long最小值
ULONG_MAX unsigned long 最大值
FLT_MANT_DIG float 类型的尾数
FLT_DIG float 类型的最少有效数字位数
FLT_MIN_10_EXP 带有所有有效数的float类型的负指数的最小值（以10为底）
FLT_MAX_10_EXP float类型的正指数的最大值（以10为底）
FLT_MIN 保留所有精度的float类型正数最小值
FLT_MAX float类型正数最大值
来自于C++手冊的解释：
| name | expresses | value* |
|---|---|---|
| CHAR_BIT | Number of bits in a char object (byte) |
8 or greater* |
| SCHAR_MIN | Minimum value for an object of type signed char
|
-127 (-27+1) or less* |
| SCHAR_MAX | Maximum value for an object of type signed char
|
127 (27-1) or greater* |
| UCHAR_MAX | Maximum value for an object of type unsigned char
|
255 (28-1) or greater* |
| CHAR_MIN | Minimum value for an object of type char
|
either SCHAR_MIN or 0
|
| CHAR_MAX | Maximum value for an object of type char
|
either SCHAR_MAX or UCHAR_MAX |
| MB_LEN_MAX | Maximum number of bytes in a multibyte character, for any locale |
1 or greater* |
| SHRT_MIN | Minimum value for an object of type short int
|
-32767 (-215+1) or less* |
| SHRT_MAX | Maximum value for an object of type short int
|
32767 (215-1) or greater* |
| USHRT_MAX | Maximum value for an object of type unsigned short int
|
65535 (216-1) or greater* |
| INT_MIN | Minimum value for an object of type int
|
-32767 (-215+1) or less* |
| INT_MAX | Maximum value for an object of type int
|
32767 (215-1) or greater* |
| UINT_MAX | Maximum value for an object of type unsigned int
|
65535 (216-1) or greater* |
| LONG_MIN | Minimum value for an object of type long int
|
-2147483647 (-231+1) or less* |
| LONG_MAX | Maximum value for an object of type long int
|
2147483647 (231-1) or greater* |
| ULONG_MAX | Maximum value for an object of type unsigned long int
|
4294967295 (232-1) or greater* |
| LLONG_MIN | Minimum value for an object of type long long int
|
-9223372036854775807 (-263+1) or less* |
| LLONG_MAX | Maximum value for an object of type long long int
|
9223372036854775807 (263-1) or greater* |
| ULLONG_MAX | Maximum value for an object of type unsigned long long int
|
18446744073709551615 (264-1) or greater* |