avr_inttypes(3)

📦 version 2.2.1, in fedora 43, fedora 44, opensuse-leap 16.0

👑 avr_inttypes — avr-libc, section 3 💅

okay bestie, sit down, hydrate, because this is the <inttypes.h> page and it is long. it's giving "reference material" and honestly? we're obsessed. this is part 1, so buckle up, more is coming. 🦋

✨ NAME ✨

avr_inttypes — the header that hands you portable integer types and the exact little format-specifier macros so your printf() and scanf() stop being a guessing game 💖

🌸 SYNOPSIS 🌸

🗺️ Far pointers for memory access >64K

typedef int32_t int_farptr_t
typedef uint32_t uint_farptr_t

🎀 macros for printf and scanf format specifiers

For C++, these are only included if __STDC_LIMIT_MACROS is defined before including <inttypes.h>. not optional, not a suggestion, define it before, periodt.

#define PRId8   'd'
#define PRIdLEAST8   'd'
#define PRIdFAST8   'd'
#define PRIi8   'i'
#define PRIiLEAST8   'i'
#define PRIiFAST8   'i'
#define PRId16   'd'
#define PRIdLEAST16   'd'
#define PRIdFAST16   'd'
#define PRIi16   'i'
#define PRIiLEAST16   'i'
#define PRIiFAST16   'i'
#define PRId32   'ld'
#define PRIdLEAST32   'ld'
#define PRIdFAST32   'ld'
#define PRIi32   'li'
#define PRIiLEAST32   'li'
#define PRIiFAST32   'li'
#define PRIdPTR   PRId16
#define PRIiPTR   PRIi16
#define PRIo8   'o'
#define PRIoLEAST8   'o'
#define PRIoFAST8   'o'
#define PRIu8   'u'
#define PRIuLEAST8   'u'
#define PRIuFAST8   'u'
#define PRIx8   'x'
#define PRIxLEAST8   'x'
#define PRIxFAST8   'x'
#define PRIX8   'X'
#define PRIXLEAST8   'X'
#define PRIXFAST8   'X'
#define PRIo16   'o'
#define PRIoLEAST16   'o'
#define PRIoFAST16   'o'
#define PRIu16   'u'
#define PRIuLEAST16   'u'
#define PRIuFAST16   'u'
#define PRIx16   'x'
#define PRIxLEAST16   'x'
#define PRIxFAST16   'x'
#define PRIX16   'X'
#define PRIXLEAST16   'X'
#define PRIXFAST16   'X'
#define PRIo32   'lo'
#define PRIoLEAST32   'lo'
#define PRIoFAST32   'lo'
#define PRIu32   'lu'
#define PRIuLEAST32   'lu'
#define PRIuFAST32   'lu'
#define PRIx32   'lx'
#define PRIxLEAST32   'lx'
#define PRIxFAST32   'lx'
#define PRIX32   'lX'
#define PRIXLEAST32   'lX'
#define PRIXFAST32   'lX'
#define PRIoPTR   PRIo16
#define PRIuPTR   PRIu16
#define PRIxPTR   PRIx16
#define PRIXPTR   PRIX16
#define SCNd8   'hhd'
#define SCNdLEAST8   'hhd'
#define SCNdFAST8   'hhd'
#define SCNi8   'hhi'
#define SCNiLEAST8   'hhi'
#define SCNiFAST8   'hhi'
#define SCNd16   'd'
#define SCNdLEAST16   'd'
#define SCNdFAST16   'd'
#define SCNi16   'i'
#define SCNiLEAST16   'i'
#define SCNiFAST16   'i'
#define SCNd32   'ld'
#define SCNdLEAST32   'ld'
#define SCNdFAST32   'ld'
#define SCNi32   'li'
#define SCNiLEAST32   'li'
#define SCNiFAST32   'li'
#define SCNdPTR   SCNd16
#define SCNiPTR   SCNi16
#define SCNo8   'hho'
#define SCNoLEAST8   'hho'
#define SCNoFAST8   'hho'
#define SCNu8   'hhu'
#define SCNuLEAST8   'hhu'
#define SCNuFAST8   'hhu'
#define SCNx8   'hhx'
#define SCNxLEAST8   'hhx'
#define SCNxFAST8   'hhx'
#define SCNo16   'o'
#define SCNoLEAST16   'o'
#define SCNoFAST16   'o'
#define SCNu16   'u'
#define SCNuLEAST16   'u'
#define SCNuFAST16   'u'
#define SCNx16   'x'
#define SCNxLEAST16   'x'
#define SCNxFAST16   'x'
#define SCNo32   'lo'
#define SCNoLEAST32   'lo'
#define SCNoFAST32   'lo'
#define SCNu32   'lu'
#define SCNuLEAST32   'lu'
#define SCNuFAST32   'lu'
#define SCNx32   'lx'
#define SCNxLEAST32   'lx'
#define SCNxFAST32   'lx'
#define SCNoPTR   SCNo16
#define SCNuPTR   SCNu16
#define SCNxPTR   SCNx16

like. that's the whole roster. every single one is here, no cap. 🔥

💜 Detailed Description 💜

#include <inttypes.h>

so here's the tea, bestie. this header file includes the exact-width integer definitions from <stdint.h>, and then it extends them with extra facilities that the implementation provides. it's the stdint glow-up. ✨

right now, those extensions are:

two extra integer types that can hold a 'far' pointer — and by far we mean a code pointer that can address more than 64 KB 🗺️
standard names for all the printf and scanf formatting options that are supported by the <stdio.h>: Standard IO facilities.

and lowkey important: since the library does not support the full range of conversion specifiers from ISO 9899:1999, only the conversions that are actually implemented get listed here. no fake options, only the real ones. 💅

the whole idea behind these conversion macros? for each of the types defined by <stdint.h>, you get a macro that portably lets you format an object of that type in printf() or scanf() operations. no more hardcoding %d and praying. 🙈

Example:

#include <inttypes.h>

uint8_t smallval;
int32_t longval;
...
printf("The hexadecimal value of smallval is %" PRIx8
       ", the decimal value of longval is %" PRId32 ".0,
   smallval, longval);

see how the macro sits right there in the middle of the string, chillin' between the quotes? that's the whole vibe. 🫶

more of this page is coming in part 2, so don't go anywhere bestie 💖

the d girlies (decimal printf): 🍓

#define PRId16 'd' — decimal printf format for int16_t 💅
#define PRId32 'ld' — decimal printf format for int32_t
#define PRId8 'd' — decimal printf format for int8_t
#define PRIdFAST16 'd' — decimal printf format for int_fast16_t
#define PRIdFAST32 'ld' — decimal printf format for int_fast32_t
#define PRIdFAST8 'd' — decimal printf format for int_fast8_t
#define PRIdLEAST16 'd' — decimal printf format for int_least16_t
#define PRIdLEAST32 'ld' — decimal printf format for int_least32_t
#define PRIdLEAST8 'd' — decimal printf format for int_least8_t
#define PRIdPTR PRId16 — decimal printf format for intptr_t (it literally just is PRId16, no cap 🫶)

the i besties (integer printf): 🌸

#define PRIi16 'i' — integer printf format for int16_t
#define PRIi32 'li' — integer printf format for int32_t
#define PRIi8 'i' — integer printf format for int8_t
#define PRIiFAST16 'i' — integer printf format for int_fast16_t
#define PRIiFAST32 'li' — integer printf format for int_fast32_t
#define PRIiFAST8 'i' — integer printf format for int_fast8_t
#define PRIiLEAST16 'i' — integer printf format for int_least16_t
#define PRIiLEAST32 'li' — integer printf format for int_least32_t
#define PRIiLEAST8 'i' — integer printf format for int_least8_t
#define PRIiPTR PRIi16 — integer printf format for intptr_t

the o cuties (octal printf): 🎀

#define PRIo16 'o' — octal printf format for uint16_t
#define PRIo32 'lo' — octal printf format for uint32_t
#define PRIo8 'o' — octal printf format for uint8_t
#define PRIoFAST16 'o' — octal printf format for uint_fast16_t
#define PRIoFAST32 'lo' — octal printf format for uint_fast32_t
#define PRIoFAST8 'o' — octal printf format for uint_fast8_t
#define PRIoLEAST16 'o' — octal printf format for uint_least16_t
#define PRIoLEAST32 'lo' — octal printf format for uint_least32_t
#define PRIoLEAST8 'o' — octal printf format for uint_least8_t
#define PRIoPTR PRIo16 — octal printf format for uintptr_t

the u squad (decimal-but-unsigned printf): 💜

#define PRIu16 'u' — decimal printf format for uint16_t
#define PRIu32 'lu' — decimal printf format for uint32_t
#define PRIu8 'u' — decimal printf format for uint8_t
#define PRIuFAST16 'u' — decimal printf format for uint_fast16_t
#define PRIuFAST32 'lu' — decimal printf format for uint_fast32_t
#define PRIuFAST8 'u' — decimal printf format for uint_fast8_t
#define PRIuLEAST16 'u' — decimal printf format for uint_least16_t
#define PRIuLEAST32 'lu' — decimal printf format for uint_least32_t
#define PRIuLEAST8 'u' — decimal printf format for uint_least8_t
#define PRIuPTR PRIu16 — decimal printf format for uintptr_t

the hex girlies (lowercase x AND uppercase X, both slaying): 🔥

#define PRIx16 'x' — hexadecimal printf format for uint16_t
#define PRIX16 'X' — uppercase hexadecimal printf format for uint16_t
#define PRIx32 'lx' — hexadecimal printf format for uint32_t
#define PRIX32 'lX' — uppercase hexadecimal printf format for uint32_t
#define PRIx8 'x' — hexadecimal printf format for uint8_t
#define PRIX8 'X' — uppercase hexadecimal printf format for uint8_t
#define PRIxFAST16 'x' — hexadecimal printf format for uint_fast16_t
#define PRIXFAST16 'X' — uppercase hexadecimal printf format for uint_fast16_t
#define PRIxFAST32 'lx' — hexadecimal printf format for uint_fast32_t
#define PRIXFAST32 'lX' — uppercase hexadecimal printf format for uint_fast32_t
#define PRIxFAST8 'x' — hexadecimal printf format for uint_fast8_t
#define PRIXFAST8 'X' — uppercase hexadecimal printf format for uint_fast8_t
#define PRIxLEAST16 'x' — hexadecimal printf format for uint_least16_t
#define PRIXLEAST16 'X' — uppercase hexadecimal printf format for uint_least16_t
#define PRIxLEAST32 'lx' — hexadecimal printf format for uint_least32_t
#define PRIXLEAST32 'lX' — uppercase hexadecimal printf format for uint_least32_t
#define PRIxLEAST8 'x' — hexadecimal printf format for uint_least8_t
#define PRIXLEAST8 'X' — uppercase hexadecimal printf format for uint_least8_t
#define PRIxPTR PRIx16 — hexadecimal printf format for uintptr_t
#define PRIXPTR PRIX16 — uppercase hexadecimal printf format for uintptr_t

okay and NOW we flip it, bestie — this is the scanf side of the family 🌈 same energy, but for reading values instead of printing them. Notice how the 8-bit ones get that little hh prefix (iconic, honestly) 👑

the d crew (decimal scanf): 🦋

#define SCNd16 'd' — decimal scanf format for int16_t
#define SCNd32 'ld' — decimal scanf format for int32_t
#define SCNd8 'hhd' — decimal scanf format for int8_t
#define SCNdFAST16 'd' — decimal scanf format for int_fast16_t
#define SCNdFAST32 'ld' — decimal scanf format for int_fast32_t
#define SCNdFAST8 'hhd' — decimal scanf format for int_fast8_t
#define SCNdLEAST16 'd' — decimal scanf format for int_least16_t
#define SCNdLEAST32 'ld' — decimal scanf format for int_least32_t
#define SCNdLEAST8 'hhd' — decimal scanf format for int_least8_t
#define SCNdPTR SCNd16 — decimal scanf format for intptr_t

the i crew (generic-integer scanf): ⭐

#define SCNi16 'i' — generic-integer scanf format for int16_t
#define SCNi32 'li' — generic-integer scanf format for int32_t
#define SCNi8 'hhi' — generic-integer scanf format for int8_t
#define SCNiFAST16 'i' — generic-integer scanf format for int_fast16_t
#define SCNiFAST32 'li' — generic-integer scanf format for int_fast32_t
#define SCNiFAST8 'hhi' — generic-integer scanf format for int_fast8_t
#define SCNiLEAST16 'i' — generic-integer scanf format for int_least16_t
#define SCNiLEAST32 'li' — generic-integer scanf format for int_least32_t
#define SCNiLEAST8 'hhi' — generic-integer scanf format for int_least8_t
#define SCNiPTR SCNi16 — generic-integer scanf format for intptr_t

the o crew (octal scanf): 🧚

#define SCNo16 'o' — octal scanf format for uint16_t
#define SCNo32 'lo' — octal scanf format for uint32_t
#define SCNo8 'hho' — octal scanf format for uint8_t
#define SCNoFAST16 'o' — octal scanf format for uint_fast16_t
#define SCNoFAST32 'lo' — octal scanf format for uint_fast32_t
#define SCNoFAST8 'hho' — octal scanf format for uint_fast8_t
#define SCNoLEAST16 'o' — octal scanf format for uint_least16_t
#define SCNoLEAST32 'lo' — octal scanf format for uint_least32_t
#define SCNoLEAST8 'hho' — octal scanf format for uint_least8_t
#define SCNoPTR SCNo16 — octal scanf format for uintptr_t

the u crew (decimal scanf): 🌸

#define SCNu16 'u' — decimal scanf format for uint16_t
#define SCNu32 'lu' — decimal scanf format for uint32_t
#define SCNu8 'hhu' — decimal scanf format for uint8_t
#define SCNuFAST16 'u' — decimal scanf format for uint_fast16_t
#define SCNuFAST32 'lu' — decimal scanf format for uint_fast32_t
#define SCNuFAST8 'hhu' — decimal scanf format for uint_fast8_t
#define SCNuLEAST16 'u' — decimal scanf format for uint_least16_t
#define SCNuLEAST32 'lu' — decimal scanf format for uint_least32_t
#define SCNuLEAST8 'hhu' — decimal scanf format for uint_least8_t
#define SCNuPTR SCNu16 — decimal scanf format for uintptr_t

the x crew (hexadecimal scanf): ✨

#define SCNx16 'x' — hexadecimal scanf format for uint16_t
#define SCNx32 'lx' — hexadecimal scanf format for uint32_t
#define SCNx8 'hhx' — hexadecimal scanf format for uint8_t
#define SCNxFAST16 'x' — hexadecimal scanf format for uint_fast16_t
#define SCNxFAST32 'lx' — hexadecimal scanf format for uint_fast32_t
#define SCNxFAST8 'hhx' — hexadecimal scanf format for uint_fast8_t
#define SCNxLEAST16 'x' — hexadecimal scanf format for uint_least16_t
#define SCNxLEAST32 'lx' — hexadecimal scanf format for uint_least32_t
#define SCNxLEAST8 'hhx' — hexadecimal scanf format for uint_least8_t
#define SCNxPTR SCNx16 — hexadecimal scanf format for uintptr_t

🫶 Typedef Documentation 🫶

just two little typedefs hanging out at the end, no biggie, but they MATTER if you're on one of those chips with big ol' memory spaces 💀

typedef int32_t int_farptr_t — signed integer type that can hold a pointer > 64 KB 👑
typedef uint32_t uint_farptr_t — unsigned integer type that can hold a pointer > 64 KB 💖

💜 Author 💜

Generated automatically by Doxygen for avr-libc from the source code.

and that's a wrap, bestie 🎀 this whole glow-up was auto-generated by Doxygen for avr-libc, version 2.1.0, dated Sat Jan 29 2022 — go forth and format your ints correctly, ily 💅✨

📦 where this page comes from

fedora 43: avr-libc 2.2.1-3.fc43 · BSD-3-Clause
fedora 44: avr-libc 2.2.1-5.fc44 · BSD-3-Clause
opensuse-leap 16.0: avr-libc 2.1.0-bp160.1.33 · BSD-3-Clause
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on 2026-10-14: a language model's rewrite of the original, under its terms