Standard library header <stdint.h> (C99)

This header is part of types support library, providing fixed width integer types and a part of numeric limits interface.

Types

For each of the following typedef names marked (optional), an implementation defines it if and only if the implementation provides a corresponding type.

int8_tint16_tint32_tint64_tintN_t (optional)(optional)(optional)(optional)(optional)	signed integer type with width of exactly N (typically 8, 16, 32 or 64) bits and no padding bits (typedef)
int_fast8_tint_fast16_tint_fast32_tint_fast64_tint_fastN_t (optional)	fastest signed integer type with width of at least N (typically 8, 16, 32 or 64) bits (typedef)
int_least8_tint_least16_tint_least32_tint_least64_tint_leastN_t (optional)	smallest signed integer type with width of at least N (typically 8, 16, 32 or 64) bits (if intN_t is defined, int_leastN_t designates the same type) (typedef)
intmax_t	maximum-width signed integer type other than a bit-precise integer type(since C23) (typedef)
intptr_t (optional)	signed integer type other than a bit-precise integer type(since C23) capable of holding a pointer to void (typedef)
uint8_tuint16_tuint32_tuint64_tuintN_t (optional)(optional)(optional)(optional)(optional)	unsigned integer type with width of exactly N (typically 8, 16, 32 or 64) bits and no padding bits (typedef)
uint_fast8_tuint_fast16_tuint_fast32_tuint_fast64_tuint_fastN_t (optional)	fastest unsigned integer type with width of at least N (typically 8, 16, 32 or 64) bits (typedef)
uint_least8_tuint_least16_tuint_least32_tuint_least64_tuint_leastN_t (optional)	smallest unsigned integer type with width of at least N (typically 8, 16, 32 or 64) bits (if uintN_t is defined, uint_leastN_t designates the same type) (typedef)
uintmax_t	maximum-width unsigned integer type other than a bit-precise integer type(since C23) (typedef)
uintptr_t (optional)	unsigned integer type other than a bit-precise integer type(since C23) capable of holding a pointer to void (typedef)

Macro constants

For each of the following macros marked (conditionally present), an implementation defines it if and only if the implementation defines the corresponding typedef name.

Signed integers : bit width
INTN_WIDTH (C23)(conditionally present)	bit width of intN_t (N is typically 8, 16, 32 or 64) (macro constant)
INT_FASTN_WIDTH (C23)(conditionally present)	bit width of int_fastN_t (N is typically 8, 16, 32 or 64) (macro constant)
INT_LEASTN_WIDTH (C23)(conditionally present)	bit width of int_leastN_t (N is typically 8, 16, 32 or 64) (macro constant)
INTMAX_WIDTH (C23)	bit width of intmax_t (macro constant)
INTPTR_WIDTH (C23)(conditionally present)	bit width of intptr_t (macro constant)
Signed integers : minimum value
INTN_MIN (conditionally present)	minimum value of intN_t (N is typically 8, 16, 32 or 64) (macro constant)
INT_FASTN_MIN (conditionally present)	minimum value of int_fastN_t (N is typically 8, 16, 32 or 64) (macro constant)
INT_LEASTN_MIN (conditionally present)	minimum value of int_leastN_t (N is typically 8, 16, 32 or 64) (macro constant)
INTMAX_MIN	minimum value of intmax_t (macro constant)
INTPTR_MIN (conditionally present)	minimum value of intptr_t (macro constant)
Signed integers : maximum value
INTN_MAX (conditionally present)	maximum value of intN_t (N is typically 8, 16, 32 or 64) (macro constant)
INT_FASTN_MAX (conditionally present)	maximum value of int_fastN_t (N is typically 8, 16, 32 or 64) (macro constant)
INT_LEASTN_MAX (conditionally present)	maximum value of int_leastN_t (N is typically 8, 16, 32 or 64) (macro constant)
INTMAX_MAX	maximum value of intmax_t (macro constant)
INTPTR_MAX (conditionally present)	maximum value of intptr_t (macro constant)
Unsigned integers : bit width
UINTN_WIDTH (C23)(conditionally present)	bit width of uintN_t (N is typically 8, 16, 32 or 64) (macro constant)
UINT_FASTN_WIDTH (C23)(conditionally present)	bit width of uint_fastN_t (N is typically 8, 16, 32 or 64) (macro constant)
UINT_LEASTN_WIDTH (C23)(conditionally present)	bit width of uint_leastN_t (N is typically 8, 16, 32 or 64) (macro constant)
UINTMAX_WIDTH (C23)	bit width of uintmax_t (macro constant)
UINTPTR_WIDTH (C23)(conditionally present)	bit width of uintptr_t (macro constant)
Unsigned integers : maximum value
UINTN_MAX (conditionally present)	maximum value of uintN_t (N is typically 8, 16, 32 or 64) (macro constant)
UINT_FASTN_MAX (conditionally present)	maximum value of uint_fastN_t (N is typically 8, 16, 32 or 64) (macro constant)
UINT_LEASTN_MAX (conditionally present)	maximum value of uint_leastN_t (N is typically 8, 16, 32 or 64) (macro constant)
UINTMAX_MAX	maximum value of uintmax_t (macro constant)
UINTPTR_MAX (conditionally present)	maximum value of uintptr_t (macro constant)
Characteristics of other integer types
PTRDIFF_WIDTH (C23)	bit width of ptrdiff_t (macro constant)
PTRDIFF_MIN	minimum value of ptrdiff_t (macro constant)
PTRDIFF_MAX	maximum value of ptrdiff_t (macro constant)
SIZE_WIDTH (C23)	bit width of size_t (macro constant)
SIZE_MAX	maximum value of size_t (macro constant)
SIG_ATOMIC_WIDTH (C23)	bit width of sig_atomic_t (macro constant)
SIG_ATOMIC_MIN	minimum value of sig_atomic_t (macro constant)
SIG_ATOMIC_MAX	maximum value of sig_atomic_t (macro constant)
WINT_WIDTH (C23)	bit width of wint_t (macro constant)
WINT_MIN	minimum value of wint_t (macro constant)
WINT_MAX	maximum value of wint_t (macro constant)
WCHAR_WIDTH (C23)	bit width of wchar_t (macro constant)
WCHAR_MIN	minimum value of wchar_t (macro constant)
WCHAR_MAX	maximum value of wchar_t (macro constant)

Function macros

For each of the following macros marked (conditionally present), an implementation defines it if and only if the implementation defines the corresponding typedef name.

INTN_C (conditionally present)	expands to an integer constant expression of type int_leastN_t, its value is specified by the argument (function macro)
INTMAX_C	expands to an integer constant expression of type intmax_t, its value is specified by the argument (function macro)
UINTN_C (conditionally present)	expands to an integer constant expression of type uint_leastN_t, its value is specified by the argument (function macro)
UINTMAX_C	expands to an integer constant expression of type uintmax_t, its value is specified by the argument (function macro)

Synopsis

#define __STDC_VERSION_STDINT_H__ 202311L

// see description of intN_t
typedef /* see description */ int8_t;        // optional
typedef /* see description */ int16_t;       // optional
typedef /* see description */ int32_t;       // optional
typedef /* see description */ int64_t;       // optional
typedef /* see description */ intN_t;        // optional

// see description of int_fastN_t
typedef /* see description */ int_fast8_t;
typedef /* see description */ int_fast16_t;
typedef /* see description */ int_fast32_t;
typedef /* see description */ int_fast64_t;
typedef /* see description */ int_fastN_t;   // optional

// see description of int_leastN_t
typedef /* see description */ int_least8_t;
typedef /* see description */ int_least16_t;
typedef /* see description */ int_least32_t;
typedef /* see description */ int_least64_t;
typedef /* see description */ int_leastN_t;  // optional

typedef /* see description */ intmax_t;
typedef /* see description */ intptr_t;      // optional

// see description of uintN_t
typedef /* see description */ uint8_t;       // optional
typedef /* see description */ uint16_t;      // optional
typedef /* see description */ uint32_t;      // optional
typedef /* see description */ uint64_t;      // optional
typedef /* see description */ uintN_t;       // optional

// see description of uint_fastN_t
typedef /* see description */ uint_fast8_t;
typedef /* see description */ uint_fast16_t;
typedef /* see description */ uint_fast32_t;
typedef /* see description */ uint_fast64_t;
typedef /* see description */ uint_fastN_t;  // optional

// see description of uint_leastN_t
typedef /* see description */ uint_least8_t;
typedef /* see description */ uint_least16_t;
typedef /* see description */ uint_least32_t;
typedef /* see description */ uint_least64_t;
typedef /* see description */ uint_leastN_t; // optional

typedef /* see description */ uintmax_t;
typedef /* see description */ uintptr_t;     // optional

#define INTN_MIN          /* see description */
#define INTN_MAX          /* see description */
#define UINTN_MAX         /* see description */
#define INTN_WIDTH        /* see description */
#define UINTN_WIDTH       /* see description */

#define INT_FASTN_MIN     /* see description */
#define INT_FASTN_MAX     /* see description */
#define UINT_FASTN_MAX    /* see description */
#define INT_FASTN_WIDTH   /* see description */
#define UINT_FASTN_WIDTH  /* see description */

#define INT_LEASTN_MIN    /* see description */
#define INT_LEASTN_MAX    /* see description */
#define UINT_LEASTN_MAX   /* see description */
#define INT_LEASTN_WIDTH  /* see description */
#define UINT_LEASTN_WIDTH /* see description */

#define INTMAX_MIN        /* see description */
#define INTMAX_MAX        /* see description */
#define UINTMAX_MAX       /* see description */
#define INTMAX_WIDTH      /* see description */
#define UINTMAX_WIDTH     /* see description */

#define INTPTR_MIN        /* see description */ // optional
#define INTPTR_MAX        /* see description */ // optional
#define UINTPTR_MAX       /* see description */ // optional
#define INTPTR_WIDTH      /* see description */ // optional
#define UINTPTR_WIDTH     /* see description */ // optional

#define PTRDIFF_MIN       /* see description */
#define PTRDIFF_MAX       /* see description */
#define PTRDIFF_WIDTH     /* see description */
#define SIZE_MAX          /* see description */
#define SIZE_WIDTH        /* see description */

#define SIG_ATOMIC_MIN    /* see description */
#define SIG_ATOMIC_MAX    /* see description */
#define SIG_ATOMIC_WIDTH  /* see description */

#define WCHAR_MIN         /* see description */
#define WCHAR_MAX         /* see description */
#define WCHAR_WIDTH       /* see description */

#define WINT_MIN          /* see description */
#define WINT_MAX          /* see description */
#define WINT_WIDTH        /* see description */

#define INTN_C(value)     /* see description */
#define UINTN_C(value)    /* see description */
#define INTMAX_C(value)   /* see description */
#define UINTMAX_C(value)  /* see description */

Only if the implementation defines __STDC_LIB_EXT1__ and additionally the user code defines __STDC_WANT_LIB_EXT1__ before any inclusion of <stdint.h>:

#if defined(__STDC_WANT_LIB_EXT1__)
#define RSIZE_MAX /* see description */
#endif