Fixed width integer types (since C99) (original) (raw)
Contents
- 1 Types
- 2 Macro constants
- 3 Function macros for minimum-width integer constants
- 4 Format macro constants
- 5 Example
- 6 References
- 7 See also
[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 respectivelywith 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 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 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 |
The implementation may define typedef names int_N__t, int_fast_N__t, int_least_N__t, uint_N__t, uint_fast_N__t, and uint_least_N__t when N is not 8, 16, 32 or 64. Typedef names of the form int_N__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 INT_N__C and UINT_N__C correspond to the typedef names int_least_N__t and uint_least_N__t, respectively.
[edit] 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) |
[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) |
|---|---|
| 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) |
| 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
[edit] Format macro constants
[edit] 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.
| Equivalentfor int orunsigned 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 |
[edit] 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.
| Equivalentfor int orunsigned 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 |
[edit] Example
See also C++ compatibility note regarding spaces before format macros used in this example.
#include <inttypes.h> #include <stdio.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); }
Possible output:
8 lld -9223372036854775808 +9223372036854775807 +7
[edit] 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)