Fixed width integer types (since C99) - cppreference.com

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# Fixed width integer types (since C99)

From cppreference.com
< c‎ | types

### [edit] Types

Defined in header `<stdint.h>`
`int8_t` `int16_t` `int32_t` `int64_t` | 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)
`int_fast8_t` `int_fast16_t` `int_fast32_t` `int_fast64_t` | fastest signed signed integer type with width of at least 8, 16, 32 and 64 bits respectively
`int_least8_t` `int_least16_t` `int_least32_t` `int_least64_t` | smallest signed integer type with width of at least 8, 16, 32 and 64 bits respectively
`intmax_t` | maximum width integer type
`intptr_t` | integer type capable of holding a pointer
`uint8_t` `uint16_t` `uint32_t` `uint64_t` | unsigned integer type with width of exactly 8, 16, 32 and 64 bits respectively (provided only if the implementation directly supports the type)
`uint_fast8_t` `uint_fast16_t` `uint_fast32_t` `uint_fast64_t` | fastest unsigned unsigned integer type with width of at least 8, 16, 32 and 64 bits respectively
`uint_least8_t` `uint_least16_t` `uint_least32_t` `uint_least64_t` | smallest unsigned integer type with width of at least 8, 16, 32 and 64 bits respectively
`uintmax_t` | maximum width unsigned integer type
`uintptr_t` | unsigned integer type capable of holding a pointer

### [edit] Macro constants

Defined in header `<stdint.h>`
##### Signed integers : minimum value
INT8_MIN INT16_MIN INT32_MIN INT64_MIN | minimum value of an object of type int8_t, int16_t, int32_t, int64_t (macro constant)
INT_FAST8_MIN INT_FAST16_MIN INT_FAST32_MIN INT_FAST64_MIN | minimum value of an object of type int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t (macro constant)
INT_LEAST8_MIN INT_LEAST16_MIN INT_LEAST32_MIN INT_LEAST64_MIN | minimum value of an object of type int_least8_t, int_least16_t, int_least32_t, int_least64_t (macro constant)
INTPTR_MIN | minimum value of an object of type intptr_t (macro constant)
INTMAX_MIN | minimum value of an object of type intmax_t (macro constant)
##### Signed integers : maximum value
INT8_MAX INT16_MAX INT32_MAX INT64_MAX | maximum value of an object of type int8_t, int16_t, int32_t, int64_t (macro constant)
INT_FAST8_MAX INT_FAST16_MAX INT_FAST32_MAX INT_FAST64_MAX | maximum value of an object of type int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t (macro constant)
INT_LEAST8_MAX INT_LEAST16_MAX INT_LEAST32_MAX INT_LEAST64_MAX | maximum value of an object of type int_least8_t, int_least16_t, int_least32_t, int_least64_t (macro constant)
INTPTR_MAX | maximum value of an object of type intptr_t (macro constant)
INTMAX_MAX | maximum value of an object of type intmax_t (macro constant)
##### Unsigned integers : maximum value
UINT8_MAX UINT16_MAX UINT32_MAX UINT64_MAX | maximum value of an object of type uint8_t, uint16_t, uint32_t, uint64_t (macro constant)
UINT_FAST8_MAX UINT_FAST16_MAX UINT_FAST32_MAX UINT_FAST64_MAX | maximum value of an object of type uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t (macro constant)
UINT_LEAST8_MAX UINT_LEAST16_MAX UINT_LEAST32_MAX UINT_LEAST64_MAX | maximum value of an object of type uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t (macro constant)
UINTPTR_MAX | maximum value of an object of type uintptr_t (macro constant)
UINTMAX_MAX | maximum value of an object of type uintmax_t (macro constant)

### [edit] Format macro constants

| This section is incomplete Reason: will look better as a table

Defined in header `<inttypes.h>`
##### Format constants for the fprintf family of functions
PRId8 PRId16 PRId32 PRId64 PRIdLEAST8 PRIdLEAST16 PRIdLEAST32 PRIdLEAST64 PRIdFAST8 PRIdFAST16 PRIdFAST32 PRIdFAST64 PRIdMAX PRIdPTR | format conversion specifier to output a signed decimal integer value of type int8_t, int16_t, int32_t, int64_t, int_least8_t, int_least16_t, int_least32_t, int_least64_t, int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t, intmax_t, intptr_t respectively, equivalent to `%d` for int (macro constant)
PRIi8 PRIi16 PRIi32 PRIi64 PRIiLEAST8 PRIiLEAST16 PRIiLEAST32 PRIiLEAST64 PRIiFAST8 PRIiFAST16 PRIiFAST32 PRIiFAST64 PRIiMAX PRIiPTR | format conversion specifier to output a signed decimal integer value of type int8_t, int16_t, int32_t, int64_t, int_least8_t, int_least16_t, int_least32_t, int_least64_t, int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t, intmax_t, intptr_t respectively, equivalent to `%i` for int (macro constant)
PRIu8 PRIu16 PRIu32 PRIu64 PRIuLEAST8 PRIuLEAST16 PRIuLEAST32 PRIuLEAST64 PRIuFAST8 PRIuFAST16 PRIuFAST32 PRIuFAST64 PRIuMAX PRIuPTR | format conversion specifier to output an unsigned decimal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to `%u` for unsigned int (macro constant)
PRIo8 PRIo16 PRIo32 PRIo64 PRIoLEAST8 PRIoLEAST16 PRIoLEAST32 PRIoLEAST64 PRIoFAST8 PRIoFAST16 PRIoFAST32 PRIoFAST64 PRIoMAX PRIoPTR | format conversion specifier to output an unsigned octal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to `%o` for unsigned int (macro constant)
PRIx8 PRIx16 PRIx32 PRIx64 PRIxLEAST8 PRIxLEAST16 PRIxLEAST32 PRIxLEAST64 PRIxFAST8 PRIxFAST16 PRIxFAST32 PRIxFAST64 PRIxMAX PRIxPTR | format conversion specifier to output an unsigned hexadecimal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to `%x` for unsigned int (macro constant)
PRIX8 PRIX16 PRIX32 PRIX64 PRIXLEAST8 PRIXLEAST16 PRIXLEAST32 PRIXLEAST64 PRIXFAST8 PRIXFAST16 PRIXFAST32 PRIXFAST64 PRIXMAX PRIXPTR | format conversion specifier to output an unsigned uppercase hexadecimal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to `%X` for unsigned int (macro constant)
##### Format constants for the fscanf family of functions
SCNd8 SCNd16 SCNd32 SCNd64 SCNdLEAST8 SCNdLEAST16 SCNdLEAST32 SCNdLEAST64 SCNdFAST8 SCNdFAST16 SCNdFAST32 SCNdFAST64 SCNdMAX SCNdPTR | format conversion specifier to input a signed decimal integer value of type int8_t, int16_t, int32_t, int64_t, int_least8_t, int_least16_t, int_least32_t, int_least64_t, int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t, intmax_t, intptr_t respectively, equivalent to `%d` for int (macro constant)
SCNi8 SCNi16 SCNi32 SCNi64 SCNiLEAST8 SCNiLEAST16 SCNiLEAST32 SCNiLEAST64 SCNiFAST8 SCNiFAST16 SCNiFAST32 SCNiFAST64 SCNiMAX SCNiPTR | format conversion specifier to input a signed decimal/octal/hexadecimal integer value of type int8_t, int16_t, int32_t, int64_t, int_least8_t, int_least16_t, int_least32_t, int_least64_t, int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t, intmax_t, intptr_t respectively, equivalent to `%i` for int (macro constant)
SCNu8 SCNu16 SCNu32 SCNu64 SCNuLEAST8 SCNuLEAST16 SCNuLEAST32 SCNuLEAST64 SCNuFAST8 SCNuFAST16 SCNuFAST32 SCNuFAST64 SCNuMAX SCNuPTR | format conversion specifier to input an unsigned decimal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to `%u` for unsigned int (macro constant)
SCNo8 SCNo16 SCNo32 SCNo64 SCNoLEAST8 SCNoLEAST16 SCNoLEAST32 SCNoLEAST64 SCNoFAST8 SCNoFAST16 SCNoFAST32 SCNoFAST64 SCNoMAX SCNoPTR | format conversion specifier to input an unsigned octal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to `%o` for unsigned int (macro constant)
SCNx8 SCNx16 SCNx32 SCNx64 SCNxLEAST8 SCNxLEAST16 SCNxLEAST32 SCNxLEAST64 SCNxFAST8 SCNxFAST16 SCNxFAST32 SCNxFAST64 SCNxMAX SCNxPTR | format conversion specifier to input an unsigned hexadecimal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to `%x` for unsigned int (macro constant)
SCNX8 SCNX16 SCNX32 SCNX64 SCNXLEAST8 SCNXLEAST16 SCNXLEAST32 SCNXLEAST64 SCNXFAST8 SCNXFAST16 SCNXFAST32 SCNXFAST64 SCNXMAX SCNXPTR | format conversion specifier to input an unsigned uppercase hexadecimal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to `%X` for unsigned int (macro constant)

### [edit] Example

Run this code

    #include <stdio.h>
    #include <inttypes.h>

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

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

        return 0;
    }

Possible output:

    8
    ld
    -9223372036854775808
    +9223372036854775807
    +7

### [edit] See also

- Arithmetic types
- C++ type system overview
- Type support (basic types, RTTI, type traits)

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