Fixed width integer types (since C++11) - cppreference.com

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# Fixed width integer types (since C++11)

From cppreference.com
< cpp‎ | types

### [edit] Types

Defined in header `<cstdint>`
int8_tint16_tint32_tint64_t (optional) | signed integer type with width of exactly 8, 16, 32 and 64 bits respectively with no padding bits and using 2's complement for negative values (provided only if the implementation directly supports the type) (typedef) [edit]
int_fast8_tint_fast16_tint_fast32_tint_fast64_t | fastest signed integer type with width of at least 8, 16, 32 and 64 bits respectively (typedef) [edit]
int_least8_tint_least16_tint_least32_tint_least64_t | smallest signed integer type with width of at least 8, 16, 32 and 64 bits respectively (typedef) [edit]
intmax_t | maximum width integer type (typedef) [edit]
intptr_t (optional) | integer type capable of holding a pointer (typedef) [edit]
uint8_tuint16_tuint32_tuint64_t (optional) | unsigned integer type with width of exactly 8, 16, 32 and 64 bits respectively (provided only if the implementation directly supports the type) (typedef) [edit]
uint_fast8_tuint_fast16_tuint_fast32_tuint_fast64_t | fastest unsigned integer type with width of at least 8, 16, 32 and 64 bits respectively (typedef) [edit]
uint_least8_tuint_least16_tuint_least32_tuint_least64_t | smallest unsigned integer type with width of at least 8, 16, 32 and 64 bits respectively (typedef) [edit]
uintmax_t | maximum width unsigned integer type (typedef) [edit]
uintptr_t (optional) | unsigned integer type capable of holding a pointer (typedef) [edit]

### [edit] Macro constants

Defined in header `<cstdint>`
##### Signed integers : minimum value
INT8_MININT16_MININT32_MININT64_MIN | minimum value of an object of type int8_t, int16_t, int32_t, int64_t (macro constant) [edit]
INT_FAST8_MININT_FAST16_MININT_FAST32_MININT_FAST64_MIN | minimum value of an object of type int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t (macro constant) [edit]
INT_LEAST8_MININT_LEAST16_MININT_LEAST32_MININT_LEAST64_MIN | minimum value of an object of type int_least8_t, int_least16_t, int_least32_t, int_least64_t (macro constant) [edit]
INTPTR_MIN | minimum value of an object of type intptr_t (macro constant) [edit]
INTMAX_MIN | minimum value of an object of type intmax_t (macro constant) [edit]
##### Signed integers : maximum value
INT8_MAXINT16_MAXINT32_MAXINT64_MAX | maximum value of an object of type int8_t, int16_t, int32_t, int64_t (macro constant) [edit]
INT_FAST8_MAXINT_FAST16_MAXINT_FAST32_MAXINT_FAST64_MAX | maximum value of an object of type int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t (macro constant) [edit]
INT_LEAST8_MAXINT_LEAST16_MAXINT_LEAST32_MAXINT_LEAST64_MAX | maximum value of an object of type int_least8_t, int_least16_t, int_least32_t, int_least64_t (macro constant) [edit]
INTPTR_MAX | maximum value of an object of type intptr_t (macro constant) [edit]
INTMAX_MAX | maximum value of an object of type intmax_t (macro constant) [edit]
##### Unsigned integers : maximum value
UINT8_MAXUINT16_MAXUINT32_MAXUINT64_MAX | maximum value of an object of type uint8_t, uint16_t, uint32_t, uint64_t (macro constant) [edit]
UINT_FAST8_MAXUINT_FAST16_MAXUINT_FAST32_MAXUINT_FAST64_MAX | maximum value of an object of type uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t (macro constant) [edit]
UINT_LEAST8_MAXUINT_LEAST16_MAXUINT_LEAST32_MAXUINT_LEAST64_MAX | maximum value of an object of type uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t (macro constant) [edit]
UINTPTR_MAX | maximum value of an object of type uintptr_t (macro constant) [edit]
UINTMAX_MAX | maximum value of an object of type uintmax_t (macro constant) [edit]

### [edit] Function macros for minimum-width integer constants

INT8_CINT16_CINT32_CINT64_C | expands to an integer constant expression having the value specified by its argument and the type int_least8_t, int_least16_t, int_least32_t, int_least64_t respectively (function macro) [edit]
INTMAX_C | expands to an integer constant expression having the value specified by its argument and the type intmax_t (function macro) [edit]
UINT8_CUINT16_CUINT32_CUINT64_C | expands to an integer constant expression having the value specified by its argument and the type uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t respectively (function macro) [edit]
UINTMAX_C | expands to an integer constant expression having the value specified by its argument and the type uintmax_t (function macro) [edit]

    #include <cstdint>
    UINT64_C(0x123) // expands to a literal of type uint64_t and value 0x123

### [edit] Format macro constants

Defined in header `<cinttypes>`

#### [edit] Format constants for the std::fprintf family of functions

Equivalent for int or unsigned int | Description | Macros for data types
--- | --- | ---
std::intx_t | std::int_leastx_t | std::int_fastx_t | std::intmax_t | std::intptr_t
x = 8, 16, 32 or 64
`d` | output of a signed decimal integer value | PRIdx | PRIdLEASTx | PRIdFASTx | PRIdMAX | PRIdPTR
`i` | PRIix | PRIiLEASTx | PRIiFASTx | PRIiMAX | PRIiPTR
`u` | output of an unsigned decimal integer value | PRIux | PRIuLEASTx | PRIuFASTx | PRIuMAX | PRIuPTR
`o` | output of an unsigned octal integer value | PRIox | PRIoLEASTx | PRIoFASTx | PRIoMAX | PRIoPTR
`x` | output of an unsigned lowercase hexadecimal integer value | PRIxx | PRIxLEASTx | PRIxFASTx | PRIxMAX | PRIxPTR
`X` | output of an unsigned uppercase hexadecimal integer value | PRIXx | PRIXLEASTx | PRIXFASTx | PRIXMAX | PRIXPTR

#### [edit] Format constants for the std::fscanf family of functions

Equivalent for int or unsigned int | Description | Macros for data types
--- | --- | ---
std::intx_t | std::int_leastx_t | std::int_fastx_t | std::intmax_t | std::intptr_t
x = 8, 16, 32 or 64
`d` | input of a signed decimal integer value | SCNdx | SCNdLEASTx | SCNdFASTx | SCNdMAX | SCNdPTR
`i` | input of a signed integer value | SCNix | SCNiLEASTx | SCNiFASTx | SCNiMAX | SCNiPTR
`u` | input of an unsigned decimal integer value | SCNux | SCNuLEASTx | SCNuFASTx | SCNuMAX | SCNuPTR
`o` | input of an unsigned octal integer value | SCNox | SCNoLEASTx | SCNoFASTx | SCNoMAX | SCNoPTR
`x` | input of an unsigned hexadecimal integer value | SCNxx | SCNxLEASTx | SCNxFASTx | SCNxMAX | SCNxPTR

### [edit] Notes

Because C++ interprets a character immediately following a string literal as a user-defined string literal, C code such as printf("%"PRId64"\n",n); is invalid C++ and requires a space before `PRId64`.

The C99 standard suggests that C++ implementations should not define the above limit, constant, or format macros unless the macros `__STDC_LIMIT_MACROS`, `__STDC_CONSTANT_MACROS` or `__STDC_FORMAT_MACROS` (respectively) are defined before including the relevant C header (`stdint.h` or `inttypes.h`). This recommendation was not adopted by any C++ standard and was removed in C11. However, some implementations (such as glibc 2.17) try to apply this rule, and it may be necessary to define the `__STDC` macros; C++ compilers may try to work around this by automatically defining them in some circumstances.

### [edit] Example

Run this code

    #include <cstdio>
    #include <cinttypes>

    int main()
    {
        std::printf("%zu\n", sizeof(std::int64_t));
        std::printf("%s\n", PRId64);
        std::printf("%+" PRId64 "\n", INT64_MIN);
        std::printf("%+" PRId64 "\n", INT64_MAX);

        std::int64_t n = 7;
        std::printf("%+" PRId64 "\n", n);
    }

Possible output:

    8
    lld
    -9223372036854775808
    +9223372036854775807
    +7

### [edit] See also

- Fundamental types

C documentation for Fixed width integer types

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