6.7.5 Scan Format Macros for Unsigned Integers

Placeholder macros that can be used with the scanf family of functions when reading in unsigned integer values.

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

Include

<inttypes.h>

Remarks

The macros in following table expand to character string literals representing placeholders that can be used with the printf family of functions when reading in unsigned integer values.


Macro Name	Description
`SCNo8`	Octal placeholder string for an unsigned 8-bit integer type (`uint8_t`).
`SCNo16`	Octal placeholder string for an unsigned 16-bit integer type (`uint16_t`).
`SCNo32`	Octal placeholder string for an unsigned 32-bit integer type (`uint32_t`).
`SCNo64`	Octal placeholder string for an unsigned 64-bit integer type (`uint64_t`), where supported (see Attention note).
`SCNu8`	Unsigned decimal placeholder string for an unsigned 8-bit integer type (`uint8_t`).
`SCNu16`	Unsigned decimal placeholder string for an unsigned 16-bit integer type (`uint16_t`).
`SCNu32`	Unsigned decimal placeholder string for an unsigned 32-bit integer type (`uint32_t`).
`SCNu64`	Unsigned decimal placeholder string for an unsigned 64-bit integer type (`uint64_t`), where supported (see Attention note).
`SCNx8`	Hexadecimal placeholder string for an unsigned 8-bit integer type (`uint8_t`).
`SCNx16`	Hexadecimal placeholder string for an unsigned 16-bit integer type (`uint16_t`).
`SCNx32`	Hexadecimal placeholder string for an unsigned 32-bit integer type (`uint32_t`).
`SCNx64`	Hexadecimal placeholder string for an unsigned 64-bit integer type (`uint64_t`), where supported (see Attention note).
`SCNoFAST8`	Octal placeholder string for the fastest unsigned integer type with a width of at least 8 bits (`uint_fast8_t`).
`SCNoFAST16`	Octal placeholder string for the fastest unsigned integer type with a width of at least 16 bits (`uint_fast16_t`).
`SCNoFAST32`	Octal placeholder string for the fastest unsigned integer type with a width of at least 32 bits (`uint_fast32_t`).
`SCNoFAST64`	Octal placeholder string for the fastest unsigned integer type with a width of at least 64 bits (`uint_fast64_t`), where supported (see Attention note).
`SCNuFAST8`	Unsigned decimal placeholder string for the fastest unsigned integer type with a width of at least 8 bits (`uint_fast8_t`).
`SCNuFAST16`	Unsigned decimal placeholder string for the fastest unsigned integer type with a width of at least 16 bits (`uint_fast16_t`).
`SCNuFAST32`	Unsigned decimal placeholder string for the fastest unsigned integer type with a width of at least 32 bits (`uint_fast32_t`).
`SCNuFAST64`	Unsigned decimal placeholder string for the fastest unsigned integer type with a width of at least 64 bits (`uint_fast64_t`), where supported (see Attention note).
`SCNxFAST8`	Hexadecimal placeholder string for the fastest unsigned integer type with a width of at least 8 bits (`uint_fast8_t`).
`SCNxFAST16`	Hexadecimal placeholder string for the fastest unsigned integer type with a width of at least 16 bits (`uint_fast16_t`).
`SCNxFAST32`	Hexadecimal placeholder string for the fastest unsigned integer type with a width of at least 32 bits (`uint_fast32_t`).
`SCNxFAST64`	Octal placeholder string for the fastest unsigned integer type with a width of at least 64 bits (`uint_fast64_t`), where supported (see Attention note).
`SCNoLEAST8`	Octal placeholder string for a unsigned integer type with a width of at least 8 bits (`uint_least8_t`).
`SCNoLEAST16`	Octal placeholder string for a unsigned integer type with a width of at least 16 bits (`uint_least8_t`).
`SCNoLEAST32`	Octal placeholder string for a unsigned integer type with a width of at least 32 bits (`uint_least8_t`).
`SCNoLEAST64`	Octal placeholder string for a unsigned integer type with a width of at least 64 bits (`uint_least8_t`), where supported.
`SCNuLEAST8`	Unsigned decimal placeholder string for a unsigned integer type with a width of at least 8 bits (`uint_least8_t`).
`SCNuLEAST16`	Unsigned decimal placeholder string for a unsigned integer type with a width of at least 16 bits (`uint_least8_t`).
`SCNuLEAST32`	Unsigned decimal placeholder string for a unsigned integer type with a width of at least 32 bits (`uint_least8_t`).
`SCNuLEAST64`	Unsigned decimal placeholder string for a unsigned integer type with a width of at least 64 bits (`uint_least8_t`), where supported.
`SCNxLEAST8`	Hexadecimal placeholder string for a unsigned integer type with a width of at least 8 bits (`uint_least8_t`).
`SCNxLEAST16`	Hexadecimal placeholder string for a unsigned integer type with a width of at least 16 bits (`uint_least8_t`).
`SCNxLEAST32`	Hexadecimal placeholder string for a unsigned integer type with a width of at least 32 bits (`uint_least8_t`).
`SCNxLEAST64`	Hexadecimal placeholder string for a unsigned integer type with a width of at least 64 bits (`uint_least8_t`).
`SCNoMAX`	Octal placeholder string for a unsigned integer type with maximum width (`uintmax_t`).
`SCNuMAX`	Unsigned decimal placeholder string for a unsigned integer type with maximum width (`uintmax_t`).
`SCNxMAX`	Hexadecimal placeholder string for a unsigned integer type with maximum width (`uintmax_t`).
`SCNoPTR`	Octal placeholder string for the `uintptr_t` type.
`SCNuPTR`	Unsigned decimal placeholder string for the `uintptr_t` type.
`SCNxPTR`	Hexadecimal placeholder string for the `uintptr_t` type.

Example

See the notes at the beginning of this chapter or section for information on using printf() or scanf() (and other functions reading and writing the stdin or stdout streams) in the example code.

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

uint_least16_t ul16;
uintmax_t umax;

int
main(void)
{
  scanf("%" SCNxLEAST16, &ul16);
  scanf("%" SCNuMAX, &umax);
}