intN_t(3type)

NAME
intN_t, int8_t, int16_t, int32_t, int64_t, uintN_t, uint8_t, uint16_t, uint32_t, uint64_t - fixed-width basic integer types

LIBRARY
Standard C library (libc)

SYNOPSIS
#include <stdint.h>

typedef /* ... */ int8_t;
typedef /* ... */ int16_t;
typedef /* ... */ int32_t;
typedef /* ... */ int64_t;

typedef /* ... */ uint8_t;
typedef /* ... */ uint16_t;
typedef /* ... */ uint32_t;
typedef /* ... */ uint64_t;

#define INT8_WIDTH   8
#define INT16_WIDTH  16
#define INT32_WIDTH  32
#define INT64_WIDTH  64

#define UINT8_WIDTH  8
#define UINT16_WIDTH 16
#define UINT32_WIDTH 32
#define UINT64_WIDTH 64

#define INT8_MAX     /*  2**(INT8_WIDTH - 1) - 1   */
#define INT16_MAX    /*  2**(INT16_WIDTH - 1) - 1  */
#define INT32_MAX    /*  2**(INT32_WIDTH - 1) - 1  */
#define INT64_MAX    /*  2**(INT64_WIDTH - 1) - 1  */

#define INT8_MIN     /*  - 2**(INT8_WIDTH - 1)     */
#define INT16_MIN    /*  - 2**(INT16_WIDTH - 1)    */
#define INT32_MIN    /*  - 2**(INT32_WIDTH - 1)    */
#define INT64_MIN    /*  - 2**(INT64_WIDTH - 1)    */

#define UINT8_MAX    /*  2**INT8_WIDTH - 1         */
#define UINT16_MAX   /*  2**INT16_WIDTH - 1        */
#define UINT32_MAX   /*  2**INT32_WIDTH - 1        */
#define UINT64_MAX   /*  2**INT64_WIDTH - 1        */

#define INT8_C(c)    c ## /* ... */
#define INT16_C(c)   c ## /* ... */
#define INT32_C(c)   c ## /* ... */
#define INT64_C(c)   c ## /* ... */

#define UINT8_C(c)   c ## /* ... */
#define UINT16_C(c)  c ## /* ... */
#define UINT32_C(c)  c ## /* ... */
#define UINT64_C(c)  c ## /* ... */

DESCRIPTION
intN_t are signed integer types of a fixed width of exactly N bits, N being the value specified in its type name. They are be capable of storing values in the range [INTN_MIN, INTN_MAX], substituting N by the appropriate number.

uintN_t are unsigned integer types of a fixed width of exactly N bits, N being the value specified in its type name. They are capable of storing values in the range [0, UINTN_MAX], substituting N by the appropriate number.

According to POSIX, [u]int8_t, [u]int16_t, and [u]int32_t are required; [u]int64_t are only required in implementations that provide integer types with width 64; and all other types of this form are optional.

The macros [U]INTN_WIDTH expand to the width in bits of these types (N).

The macros [U]INTN_MAX expand to the maximum value that these types can hold.

The macros INTN_MIN expand to the minimum value that these types can hold.

The macros [U]INTN_C() expand their argument to an integer constant of type [u]intN_t.

The length modifiers for the [u]intN_t types for the printf(3) family of functions are expanded by macros of the forms PRIdN, PRIiN, PRIuN, and PRIxN (defined in <inttypes.h>); resulting for example in %"PRId64" or %"PRIi64" for printing int64_t values. The length modifiers for the [u]intN_t types for the scanf(3) family of functions are expanded by macros of the forms SCNdN, SCNiN, SCNuN, and SCNxN, (defined in <inttypes.h>); resulting for example in %"SCNu8" or %"SCNx8" for scanning uint8_t values.

STANDARDS
C23, POSIX.1-2024.

HISTORY

[u]intN_t
    C99, SUSv2, POSIX.1-2001.

[U]INTN_MAX
INTN_MIN
[U]INTN_C()
    C99, POSIX.1-2001.

[U]INTN_WIDTH
    C23.

Initially, SUSv2 did not include <stdint.h> as a standard header. The [u]intN_t types were instead defined in <inttypes.h>. This was remedied in POSIX.1-2001.

NOTES
The following header also provides these types: <inttypes.h>. <arpa/inet.h> also provides uint16_t and uint32_t.

SEE ALSO
intmax_t(3type), intptr_t(3type), printf(3)