avr_inttypes(3avr)

📦

version 2.2.1 · 4 versions

2.2.1 · ubuntu resolute, ubuntu stonking (latest)
2.0.0+Atmel3.6.2 · debian bookworm, ubuntu jammy
2.0.0+Atmel3.7.0 · ubuntu noble
2.2.1 · debian trixie, ubuntu questing

✨ avr_inttypes(3avr) ✨

okay bestie, welcome to avr_inttypes(3avr) 🫶 this is the whole ~vibe~ of <inttypes.h> — the header that makes your printf and scanf calls portable instead of a guessing game. no cap, this one is a bop, let's go 💅

🎀 NAME 🎀

avr_inttypes — <inttypes.h>: Integer Type conversions ✨

🦋 SYNOPSIS 🦋

🧚 Far pointers for memory access > 64K

typedef int32_t int_farptr_t
typedef uint32_t uint_farptr_t

yes bestie, two whole types that can actually point past the 64K line 👑

💖 macros for printf and scanf format specifiers

🌸 okay so important: for C++, these are only included if __STDC_LIMIT_MACROS is defined before including <inttypes.h>. don't forget it, it's giving "forgot my keys" energy otherwise 🔑

first up, the signed decimal (d) and signed integer (i) girlies — 8, 16, 32, and the PTR ones all living their best life:

#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

now the octal / unsigned / lowercase-hex / BIG-hex squad, 8-bit edition 🍓 (look at 'X' being all capital, main character behaviour fr):

#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'

same lineup but 16-bit, they grew up so fast 😭:

#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'

and 32-bit, where every single one gets that little l glow-up 💅 ('lo', 'lu', 'lx', 'lX' — the l is doing heavy lifting here):

#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'

and the PTR ones, which just straight-up borrow the 16-bit definitions. iconic, honestly:

#define PRIoPTR   PRIo16
#define PRIuPTR   PRIu16
#define PRIxPTR   PRIx16
#define PRIXPTR   PRIX16

✨ ok now we flip it — these are the scanf side, the ones that go into your variables instead of out of them. watch the hh on the 8-bit ones, that's the difference between "reads your byte" and "reads 4 bytes and eats your stack" 💀:

#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

the SCN octal/unsigned/hex besties, 8-bit, all rocking that hh:

#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'

16-bit, hh graduates to no prefix at all, so proud of them 🥹:

#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'

32-bit, l prefix activated, slay:

#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'

and the SCN PTR trio closing us out, borrowing from 16 again:

#define SCNoPTR   SCNo16
#define SCNuPTR   SCNu16
#define SCNxPTR   SCNx16

whew. breathe. that's all of them, no skips, no crumbs left behind 🫶

📖 Detailed Description 📖

#include <inttypes.h>

okay so like, what even is this header. listen: it includes all the exact-width integer definitions from <stdint.h>, and then it extends them with extra facilities that the implementation provides. it's the remix album. the deluxe edition 💿

currently, the extensions include two additional integer types that could hold a "far" pointer (i.e. a code pointer that can address more than 64 KB), plus standard names for all the printf and scanf formatting options that are supported by <stdio.h>: Standard IO facilities. and here's the tea — 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 real ones 🧚

the idea behind these conversion macros is that, for each of the types defined by <stdint.h>, a macro is supplied that portably lets you format an object of that type in printf() or scanf() operations. 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 ".\n",
   smallval, longval);

see how %" PRIx8 and %" PRId32 just slot right in there? that's the whole trick, that's the moment ✨

(part 1 of 2 — don't go anywhere bestie, there's more 💖)

💖 Macro Definition Documentation 💖

okay bestie, this is the big one. this whole section is just AVR-LibC handing you little macros so you never have to hardcode a format specifier again, because hardcoding format specifiers is how you end up on the news. each macro here expands to a string literal (or to another macro, no drama) that you drop straight into your printf/scanf format string. 🌸

quick vibe check before you scroll: these are for the printf/scanf family, and they're the whole point — you write printf("x = %" PRId16 "\n", x); and let the macro do the thinking. don't be out here typing %d for a 32-bit value, i'm begging. 😭

🍓 the `printf` girlies

💅 signed decimal — `PRId…`

PRId16 — 'd', the decimal printf format for int16_t
PRId32 — 'ld', the decimal printf format for int32_t
PRId8 — 'd', the decimal printf format for int8_t
PRIdFAST16 — 'd', the decimal printf format for int_fast16_t
PRIdFAST32 — 'ld', the decimal printf format for int_fast32_t
PRIdFAST8 — 'd', the decimal printf format for int_fast8_t
PRIdLEAST16 — 'd', the decimal printf format for int_least16_t
PRIdLEAST32 — 'ld', the decimal printf format for int_least32_t
PRIdLEAST8 — 'd', the decimal printf format for int_least8_t
PRIdPTR — expands to PRId16, the decimal printf format for intptr_t 🫶

✨ signed integer — `PRIi…`

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

🧚 octal — `PRIo…`

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

🌈 unsigned decimal — `PRIu…`

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

🔥 hex, but make it uppercase — `PRIX…`

PRIX16 — 'X', the uppercase hexadecimal printf format for uint16_t
PRIX32 — 'lX', the uppercase hexadecimal printf format for uint32_t
PRIX8 — 'X', the uppercase hexadecimal printf format for uint8_t
PRIXFAST16 — 'X', the uppercase hexadecimal printf format for uint_fast16_t
PRIXFAST32 — 'lX', the uppercase hexadecimal printf format for uint_fast32_t
PRIXFAST8 — 'X', the uppercase hexadecimal printf format for uint_fast8_t
PRIXLEAST16 — 'X', the uppercase hexadecimal printf format for uint_least16_t
PRIXLEAST32 — 'lX', the uppercase hexadecimal printf format for uint_least32_t
PRIXLEAST8 — 'X', the uppercase hexadecimal printf format for uint_least8_t
PRIXPTR — expands to PRIX16, the uppercase hexadecimal printf format for uintptr_t 👑

🦋 hex, but lowercase and chill — `PRIx…`

PRIx16 — 'x', the hexadecimal printf format for uint16_t
PRIx32 — 'lx', the hexadecimal printf format for uint32_t
PRIx8 — 'x', the hexadecimal printf format for uint8_t
PRIxFAST16 — 'x', the hexadecimal printf format for uint_fast16_t
PRIxFAST32 — 'lx', the hexadecimal printf format for uint_fast32_t
PRIxFAST8 — 'x', the hexadecimal printf format for uint_fast8_t
PRIxLEAST16 — 'x', the hexadecimal printf format for uint_least16_t
PRIxLEAST32 — 'lx', the hexadecimal printf format for uint_least32_t
PRIxLEAST8 — 'x', the hexadecimal printf format for uint_least8_t
PRIxPTR — expands to PRIx16, the hexadecimal printf format for uintptr_t 💖

🎀 the `scanf` squad

heads up bestie, the SCN… ones lowkey have different values than the PRI… ones for the 8-bit types (they use the hh length modifier), so do not, i repeat do not, get cute and swap them. 💀

🌸 signed decimal — `SCNd…`

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

⭐ generic-integer — `SCNi…`

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

🧚 octal — `SCNo…`

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

🌈 unsigned decimal — `SCNu…`

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

🔥 hexadecimal — `SCNx…`

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

🫶 Typedef Documentation 🫶

just two of them, and they're both about pointers that are way bigger than a normal one. iconic behaviour, honestly. 💅

```c typedef int32_t int_farptr_t

a signed integer type that can hold a pointer > 64 KiB 🔥

- ```c
typedef uint32_t uint_farptr_t

an unsigned integer type that can hold a pointer > 64 KiB — and btw, see also pgm_get_far_address() 🌟

✨ Author ✨

Generated automatically by Doxygen for AVR-LibC from the source code. (so like, nobody wrote this by hand, it's the robot's finest work, and we love that for it 🤖💖)

and that's a wrap bestie 🌈 this whole page is from AVR-LibC, Version 2.2.1, and it's the avr_inttypes(3avr) page — that's the name you'd yell if you wanted to look it up again. now go forth and never hardcode a format specifier again, i'm so serious. 💅✨

📦 where this page comes from

ubuntu resolute: avr-libc 1:2.2.1-1build1 · BSD-3-Clause
ubuntu stonking: avr-libc 1:2.2.1-1build1 · BSD-3-Clause
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on 2026-11-03: a language model's rewrite of the original, under its terms

avr_inttypes(3avr)

✨ avr_inttypes(3avr) ✨

🎀 NAME 🎀

🦋 SYNOPSIS 🦋

🧚 Far pointers for memory access > 64K

💖 macros for printf and scanf format specifiers

📖 Detailed Description 📖

💖 Macro Definition Documentation 💖

🍓 the printf girlies

💅 signed decimal — PRId…

✨ signed integer — PRIi…

🧚 octal — PRIo…

🌈 unsigned decimal — PRIu…

🔥 hex, but make it uppercase — PRIX…

🦋 hex, but lowercase and chill — PRIx…

🎀 the scanf squad

🌸 signed decimal — SCNd…

⭐ generic-integer — SCNi…

🧚 octal — SCNo…

🌈 unsigned decimal — SCNu…

🔥 hexadecimal — SCNx…