Fixed width integer types (since C99)
Types
| Defined in header
<stdint.h> | |
int8_tint16_tint32_tint64_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_tint_fast16_tint_fast32_tint_fast64_t
|
fastest signed integer type with width of at least 8, 16, 32 and 64 bits respectively |
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 |
intmax_t
|
maximum width integer type |
intptr_t
|
integer type capable of holding a pointer |
uint8_tuint16_tuint32_tuint64_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_tuint_fast16_tuint_fast32_tuint_fast64_t
|
fastest unsigned integer type with width of at least 8, 16, 32 and 64 bits respectively |
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 |
uintmax_t
|
maximum width unsigned integer type |
uintptr_t
|
unsigned integer type capable of holding a pointer |
The implementation may define typedef names intN_t, int_fastN_t, int_leastN_t, uintN_t, uint_fastN_t, and uint_leastN_t when N is not 8, 16, 32 or 64. Typedef names of the form intN_t may only be defined if the implementation supports an integer type of that width with no padding. Thus, uint24_t denotes an unsigned integer type with a width of exactly 24 bits.
Each of the macros listed in below is defined if and only if the implementation defines the corresponding typedef name. The macros INTN_C and UINTN_C correspond to the typedef names int_leastN_t and uint_leastN_t, respectively.
Macro constants
| Defined in header
<stdint.h> | |
Signed integers : width | |
| INT8_WIDTHINT16_WIDTHINT32_WIDTHINT64_WIDTH (C23)(optional) |
bit width of an object of type int8_t, int16_t, int32_t, int64_t (exactly 8, 16, 32, 64) (macro constant) |
| INT_FAST8_WIDTHINT_FAST16_WIDTHINT_FAST32_WIDTHINT_FAST64_WIDTH (C23) |
bit width of an object of type int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t (macro constant) |
| INT_LEAST8_WIDTHINT_LEAST16_WIDTHINT_LEAST32_WIDTHINT_LEAST64_WIDTH (C23) |
bit width of an object of type int_least8_t, int_least16_t, int_least32_t, int_least64_t (macro constant) |
| INTPTR_WIDTH (C23)(optional) |
bit width of an object of type intptr_t (macro constant) |
| INTMAX_WIDTH (C23) |
bit width of an object of type intmax_t (macro constant) |
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) |
| 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) |
| 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) |
| 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_MAXINT16_MAXINT32_MAXINT64_MAX |
maximum value of an object of type int8_t, int16_t, int32_t, int64_t (macro constant) |
| 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) |
| 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) |
| 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 : width | |
| UINT8_WIDTHUINT16_WIDTHUINT32_WIDTHUINT64_WIDTH (C23)(optional) |
bit width of an object of type uint8_t, uint16_t, uint32_t, uint64_t (exactly 8, 16, 32, 64) (macro constant) |
| UINT_FAST8_WIDTHUINT_FAST16_WIDTHUINT_FAST32_WIDTHUINT_FAST64_WIDTH (C23) |
bit width of an object of type uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t (macro constant) |
| UINT_LEAST8_WIDTHUINT_LEAST16_WIDTHUINT_LEAST32_WIDTHUINT_LEAST64_WIDTH (C23) |
bit width of an object of type uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t (macro constant) |
| UINTPTR_WIDTH (C23)(optional) |
bit width of an object of type uintptr_t (macro constant) |
| UINTMAX_WIDTH (C23) |
bit width of an object of type uintmax_t (macro constant) |
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) |
| 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) |
| 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) |
| 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) |
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) |
| INTMAX_C |
expands to an integer constant expression having the value specified by its argument and the type intmax_t (function macro) |
| 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) |
| UINTMAX_C |
expands to an integer constant expression having the value specified by its argument and the type uintmax_t (function macro) |
#include <stdint.h> UINT64_C(0x123) // might expand to 0x123ULL or 0x123UL
Format macro constants
| Defined in header
<inttypes.h> |
Format constants for the fprintf family of functions
Each of the PRI macros listed here is defined if and only if the implementation defines the corresponding typedef name.
| Equivalent for int or unsigned int |
Description | Macros for data types | ||||
|---|---|---|---|---|---|---|
[u]intx_t |
[u]int_leastx_t |
[u]int_fastx_t |
[u]intmax_t |
[u]intptr_t | ||
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 |
Format constants for the fscanf family of functions
Each of the SCN macros listed in here is defined if and only if the implementation defines the corresponding typedef name and has a suitable fscanf length modifier for the type.
| Equivalent for int or unsigned int |
Description | Macros for data types | ||||
|---|---|---|---|---|---|---|
[u]intx_t |
[u]int_leastx_t |
[u]int_fastx_t |
[u]intmax_t |
[u]intptr_t | ||
d
|
input of a signed decimal integer value | SCNdx | SCNdLEASTx | SCNdFASTx | SCNdMAX | SCNdPTR |
i
|
input of a signed integer value (base is determined by the first characters parsed) | 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 |
Example
See also C++ compatibility note regarding spaces before format macros used in this example.
Possible output:
8 lld -9223372036854775808 +9223372036854775807 +7
References
- C23 standard (ISO/IEC 9899:2024):
- 7.8.1 Macros for format specifiers (p: TBD)
- 7.18 Integer types <stdint.h> (p: TBD)
- C17 standard (ISO/IEC 9899:2018):
- 7.8.1 Macros for format specifiers (p: 158-159)
- 7.18 Integer types <stdint.h> (p: 212-216)
- C11 standard (ISO/IEC 9899:2011):
- 7.8.1 Macros for format specifiers (p: 217-218)
- 7.18 Integer types <stdint.h> (p: 289-295)
- C99 standard (ISO/IEC 9899:1999):
- 7.8.1 Macros for format specifiers (p: 198-199)
- 7.18 Integer types <stdint.h> (p: 255-261)
See also
| C++ documentation for Fixed width integer types
| |
| C++ documentation for User-defined literals (formatting macros note)
|