Fixed width integer types (since C99)

Types

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

Function macros for minimum-width integer constants

#include <stdint.h>
UINT64_C(0x123) // might expand to 0x123ULL or 0x123UL

Format macro constants

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.

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.

Example

#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);
}

8
lld
-9223372036854775808
+9223372036854775807
+7

References

• 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

• Arithmetic types