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<stdint.h>: Standard Integer Types

Exact-width integer types

Integer types having exactly the specified width

typedef signed char int8_t
typedef unsigned char uint8_t
typedef signed int int16_t
typedef unsigned int uint16_t
typedef signed long int int32_t
typedef unsigned long int uint32_t
typedef signed long long int int64_t
typedef unsigned long long int uint64_t

Integer types capable of holding object pointers

These allow you to declare variables of the same size as a pointer.

typedef int16_t intptr_t
typedef uint16_t uintptr_t

Minimum-width integer types

Integer types having at least the specified width

typedef int8_t int_least8_t
typedef uint8_t uint_least8_t
typedef int16_t int_least16_t
typedef uint16_t uint_least16_t
typedef int32_t int_least32_t
typedef uint32_t uint_least32_t
typedef int64_t int_least64_t
typedef uint64_t uint_least64_t

Fastest minimum-width integer types

Integer types being usually fastest having at least the specified width

typedef int8_t int_fast8_t
typedef uint8_t uint_fast8_t
typedef int16_t int_fast16_t
typedef uint16_t uint_fast16_t
typedef int32_t int_fast32_t
typedef uint32_t uint_fast32_t
typedef int64_t int_fast64_t
typedef uint64_t uint_fast64_t

Greatest-width integer types

Types designating integer data capable of representing any value of any integer type in the corresponding signed or unsigned category

typedef int64_t intmax_t
typedef uint64_t uintmax_t

Limits of specified-width integer types

C++ implementations should define these macros only when __STDC_LIMIT_MACROS is defined before <stdint.h> is included

#define INT8_MAX   0x7f
#define INT8_MIN   (-INT8_MAX - 1)
#define UINT8_MAX   (__CONCAT(INT8_MAX, U) * 2U + 1U)
#define INT16_MAX   0x7fff
#define INT16_MIN   (-INT16_MAX - 1)
#define UINT16_MAX   (__CONCAT(INT16_MAX, U) * 2U + 1U)
#define INT32_MAX   0x7fffffffL
#define INT32_MIN   (-INT32_MAX - 1L)
#define UINT32_MAX   (__CONCAT(INT32_MAX, U) * 2UL + 1UL)
#define INT64_MAX   0x7fffffffffffffffLL
#define INT64_MIN   (-INT64_MAX - 1LL)
#define UINT64_MAX   (__CONCAT(INT64_MAX, U) * 2ULL + 1ULL)

Limits of minimum-width integer types

#define INT_LEAST8_MAX   INT8_MAX
#define INT_LEAST8_MIN   INT8_MIN
#define UINT_LEAST8_MAX   UINT8_MAX
#define INT_LEAST16_MAX   INT16_MAX
#define INT_LEAST16_MIN   INT16_MIN
#define UINT_LEAST16_MAX   UINT16_MAX
#define INT_LEAST32_MAX   INT32_MAX
#define INT_LEAST32_MIN   INT32_MIN
#define UINT_LEAST32_MAX   UINT32_MAX
#define INT_LEAST64_MAX   INT64_MAX
#define INT_LEAST64_MIN   INT64_MIN
#define UINT_LEAST64_MAX   UINT64_MAX

Limits of fastest minimum-width integer types

#define INT_FAST8_MAX   INT8_MAX
#define INT_FAST8_MIN   INT8_MIN
#define UINT_FAST8_MAX   UINT8_MAX
#define INT_FAST16_MAX   INT16_MAX
#define INT_FAST16_MIN   INT16_MIN
#define UINT_FAST16_MAX   UINT16_MAX
#define INT_FAST32_MAX   INT32_MAX
#define INT_FAST32_MIN   INT32_MIN
#define UINT_FAST32_MAX   UINT32_MAX
#define INT_FAST64_MAX   INT64_MAX
#define INT_FAST64_MIN   INT64_MIN
#define UINT_FAST64_MAX   UINT64_MAX

Limits of integer types capable of holding object pointers

#define INTPTR_MAX   INT16_MAX
#define INTPTR_MIN   INT16_MIN
#define UINTPTR_MAX   UINT16_MAX

Limits of greatest-width integer types

#define INTMAX_MAX   INT64_MAX
#define INTMAX_MIN   INT64_MIN
#define UINTMAX_MAX   UINT64_MAX

Limits of other integer types

C++ implementations should define these macros only when __STDC_LIMIT_MACROS is defined before <stdint.h> is included

#define PTRDIFF_MAX   INT16_MAX
#define PTRDIFF_MIN   INT16_MIN
#define SIG_ATOMIC_MAX   INT8_MAX
#define SIG_ATOMIC_MIN   INT8_MIN
#define SIZE_MAX   (__CONCAT(INT16_MAX, U))

Macros for integer constants

C++ implementations should define these macros only when __STDC_CONSTANT_MACROS is defined before <stdint.h> is included.

These definitions are valid for integer constants without suffix and for macros defined as integer constant without suffix

#define INT8_C(value)   ((int8_t) value)
#define UINT8_C(value)   ((uint8_t) __CONCAT(value, U))
#define INT16_C(value)   value
#define UINT16_C(value)   __CONCAT(value, U)
#define INT32_C(value)   __CONCAT(value, L)
#define UINT32_C(value)   __CONCAT(value, UL)
#define INT64_C(value)   __CONCAT(value, LL)
#define UINT64_C(value)   __CONCAT(value, ULL)
#define INTMAX_C(value)   __CONCAT(value, LL)
#define UINTMAX_C(value)   __CONCAT(value, ULL)

Detailed Description

 #include <stdint.h> 

Use [u]intN_t if you need exactly N bits.

Since these typedefs are mandated by the C99 standard, they are preferred over rolling your own typedefs.


Define Documentation

#define INT16_C (   value)    value

define a constant of type int16_t

#define INT16_MAX   0x7fff

largest positive value an int16_t can hold.

#define INT16_MIN   (-INT16_MAX - 1)

smallest negative value an int16_t can hold.

#define INT32_C (   value)    __CONCAT(value, L)

define a constant of type int32_t

#define INT32_MAX   0x7fffffffL

largest positive value an int32_t can hold.

#define INT32_MIN   (-INT32_MAX - 1L)

smallest negative value an int32_t can hold.

#define INT64_C (   value)    __CONCAT(value, LL)

define a constant of type int64_t

#define INT64_MAX   0x7fffffffffffffffLL

largest positive value an int64_t can hold.

#define INT64_MIN   (-INT64_MAX - 1LL)

smallest negative value an int64_t can hold.

#define INT8_C (   value)    ((int8_t) value)

define a constant of type int8_t

#define INT8_MAX   0x7f

largest positive value an int8_t can hold.

#define INT8_MIN   (-INT8_MAX - 1)

smallest negative value an int8_t can hold.

#define INT_FAST16_MAX   INT16_MAX

largest positive value an int_fast16_t can hold.

#define INT_FAST16_MIN   INT16_MIN

smallest negative value an int_fast16_t can hold.

#define INT_FAST32_MAX   INT32_MAX

largest positive value an int_fast32_t can hold.

#define INT_FAST32_MIN   INT32_MIN

smallest negative value an int_fast32_t can hold.

#define INT_FAST64_MAX   INT64_MAX

largest positive value an int_fast64_t can hold.

#define INT_FAST64_MIN   INT64_MIN

smallest negative value an int_fast64_t can hold.

#define INT_FAST8_MAX   INT8_MAX

largest positive value an int_fast8_t can hold.

#define INT_FAST8_MIN   INT8_MIN

smallest negative value an int_fast8_t can hold.

#define INT_LEAST16_MAX   INT16_MAX

largest positive value an int_least16_t can hold.

#define INT_LEAST16_MIN   INT16_MIN

smallest negative value an int_least16_t can hold.

#define INT_LEAST32_MAX   INT32_MAX

largest positive value an int_least32_t can hold.

#define INT_LEAST32_MIN   INT32_MIN

smallest negative value an int_least32_t can hold.

#define INT_LEAST64_MAX   INT64_MAX

largest positive value an int_least64_t can hold.

#define INT_LEAST64_MIN   INT64_MIN

smallest negative value an int_least64_t can hold.

#define INT_LEAST8_MAX   INT8_MAX

largest positive value an int_least8_t can hold.

#define INT_LEAST8_MIN   INT8_MIN

smallest negative value an int_least8_t can hold.

#define INTMAX_C (   value)    __CONCAT(value, LL)

define a constant of type intmax_t

#define INTMAX_MAX   INT64_MAX

largest positive value an intmax_t can hold.

#define INTMAX_MIN   INT64_MIN

smallest negative value an intmax_t can hold.

#define INTPTR_MAX   INT16_MAX

largest positive value an intptr_t can hold.

#define INTPTR_MIN   INT16_MIN

smallest negative value an intptr_t can hold.

#define PTRDIFF_MAX   INT16_MAX

largest positive value a ptrdiff_t can hold.

#define PTRDIFF_MIN   INT16_MIN

smallest negative value a ptrdiff_t can hold.

#define SIG_ATOMIC_MAX   INT8_MAX

largest positive value a sig_atomic_t can hold.

#define SIG_ATOMIC_MIN   INT8_MIN

smallest negative value a sig_atomic_t can hold.

#define SIZE_MAX   (__CONCAT(INT16_MAX, U))

largest value a size_t can hold.

#define UINT16_C (   value)    __CONCAT(value, U)

define a constant of type uint16_t

#define UINT16_MAX   (__CONCAT(INT16_MAX, U) * 2U + 1U)

largest value an uint16_t can hold.

#define UINT32_C (   value)    __CONCAT(value, UL)

define a constant of type uint32_t

#define UINT32_MAX   (__CONCAT(INT32_MAX, U) * 2UL + 1UL)

largest value an uint32_t can hold.

#define UINT64_C (   value)    __CONCAT(value, ULL)

define a constant of type uint64_t

#define UINT64_MAX   (__CONCAT(INT64_MAX, U) * 2ULL + 1ULL)

largest value an uint64_t can hold.

#define UINT8_C (   value)    ((uint8_t) __CONCAT(value, U))

define a constant of type uint8_t

#define UINT8_MAX   (__CONCAT(INT8_MAX, U) * 2U + 1U)

largest value an uint8_t can hold.

largest value an uint_fast16_t can hold.

largest value an uint_fast32_t can hold.

largest value an uint_fast64_t can hold.

#define UINT_FAST8_MAX   UINT8_MAX

largest value an uint_fast8_t can hold.

largest value an uint_least16_t can hold.

largest value an uint_least32_t can hold.

largest value an uint_least64_t can hold.

#define UINT_LEAST8_MAX   UINT8_MAX

largest value an uint_least8_t can hold.

#define UINTMAX_C (   value)    __CONCAT(value, ULL)

define a constant of type uintmax_t

#define UINTMAX_MAX   UINT64_MAX

largest value an uintmax_t can hold.

#define UINTPTR_MAX   UINT16_MAX

largest value an uintptr_t can hold.


Typedef Documentation

typedef signed int int16_t

16-bit signed type.

typedef signed long int int32_t

32-bit signed type.

typedef signed long long int int64_t

64-bit signed type.

Note:
This type is not available when the compiler option -mint8 is in effect.
typedef signed char int8_t

8-bit signed type.

fastest signed int with at least 16 bits.

fastest signed int with at least 32 bits.

fastest signed int with at least 64 bits.

Note:
This type is not available when the compiler option -mint8 is in effect.

fastest signed int with at least 8 bits.

signed int with at least 16 bits.

signed int with at least 32 bits.

signed int with at least 64 bits.

Note:
This type is not available when the compiler option -mint8 is in effect.

signed int with at least 8 bits.

typedef int64_t intmax_t

largest signed int available.

typedef int16_t intptr_t

Signed pointer compatible type.

typedef unsigned int uint16_t

16-bit unsigned type.

typedef unsigned long int uint32_t

32-bit unsigned type.

typedef unsigned long long int uint64_t

64-bit unsigned type.

Note:
This type is not available when the compiler option -mint8 is in effect.
typedef unsigned char uint8_t

8-bit unsigned type.

fastest unsigned int with at least 16 bits.

fastest unsigned int with at least 32 bits.

fastest unsigned int with at least 64 bits.

Note:
This type is not available when the compiler option -mint8 is in effect.

fastest unsigned int with at least 8 bits.

unsigned int with at least 16 bits.

unsigned int with at least 32 bits.

unsigned int with at least 64 bits.

Note:
This type is not available when the compiler option -mint8 is in effect.

unsigned int with at least 8 bits.

largest unsigned int available.

Unsigned pointer compatible type.


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