6.17.14 Minimum-width Integer Constant Macros

Macros that expand to integer constants suitable for initializing objects that have integer types corresponding to types defined in <stdint.h>.

Attention: The macros for 24-bit objects are only supported when using PIC devices and MPLAB XC8. The macros for 64-bit objects are not supported when using 8-bit AVR, Baseline, or non-enhanced Mid-range PIC devices with MPLAB XC8.

Include

<stdint.h>

Remarks

Each macro name corresponds to the <stdint.h> type with a similar name. The argument to these macros shall be a decimal, octal, or hexadecimal constant with a value that does not exceed the limits for the corresponding type.


Macro	Expands to
`INT8_C`	A signed integer constant with the specified argument value and type `int_least8_t`.
`INT16_C`	A signed integer constant with the specified argument value and type `int_least16_t`.
`INT24_C`	A signed integer constant with the specified argument value and type `int_least24_t`, (see Attention note).
`INT32_C`	A signed integer constant with the specified argument value and type `int_least32_t`
`INT64_C`	A signed integer constant with the specified argument value and type `int_least64_t`, (see Attention note).
`UINT8_C`	An unsigned integer constant with the specified argument value and type `uint_least8_t`.
`UINT16_C`	An unsigned integer constant with the specified argument value and type `uint_least16_t`.
`UINT24_C`	An unsigned integer constant with the specified argument value and type `uint_least24_t`, (see Attention note).
`UINT32_C`	An unsigned integer constant with the specified argument value and type `uint_least32_t`.
`UINT64_C`	An unsigned integer constant with the specified argument value and type `uint_least64_t`, (see Attention note).

Example

#include <stdint.h>
#include <stdio.h>
#include <inttypes.h>

int
main(void)
{
        uint_least64_t ref;

        ref = 1 << (sizeof(int)*8);
        printf("ref is %" PRIxLEAST64 " (oops)\n", ref);
        ref = UINT64_C(1) << (sizeof(int)*8);
        printf("ref is %" PRIxLEAST64 " (better)\n", ref);
}

Example Output

For builds where the int type (being the type assigned to the constant 1) is 16 bits wide.

ref is 0x0 (oops)
ref is 0x10000 (better)

For builds where the int type is 32 bits wide.

ref is 0x0 (oops)
ref is 0x100000000 (better)