阈值
1 数值大小
- 头文件：
#include <stdint.h>
- 代码: 其中有一小部分在
/usr/include/limits.h 中出现
/* 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
# 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
# ifdef __WORDSIZE32_SIZE_ULONG
# define SIZE_MAX (4294967295UL)
# else
# define SIZE_MAX (4294967295U)
# endif
# 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)
/* 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
# define UINT16_C(c) c
# 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
2 文件相关阈值
- 头文件：
#include <linux/limits.h>，路径 /usr/include/linux/limits.h
- 代码
#define NR_OPEN 1024
#define NGROUPS_MAX 65536 /* supplemental group IDs are available */
#define ARG_MAX 131072 /* # bytes of args + environ for exec() */
#define LINK_MAX 127 /* # links a file may have */
#define MAX_CANON 255 /* size of the canonical input queue */
#define MAX_INPUT 255 /* size of the type-ahead buffer */
#define NAME_MAX 255 /* # chars in a file name */
#define PATH_MAX 4096 /* # chars in a path name including nul */
#define PIPE_BUF 4096 /* # bytes in atomic write to a pipe */
#define XATTR_NAME_MAX 255 /* # chars in an extended attribute name */
#define XATTR_SIZE_MAX 65536 /* size of an extended attribute value (64k) */
#define XATTR_LIST_MAX 65536 /* size of extended attribute namelist (64k) */
#define RTSIG_MAX 32