pgmspace.h(3avr)

📦

version 2.0.0+Atmel3.7.0 · 2 versions

2.0.0+Atmel3.7.0 · ubuntu noble (latest)
2.0.0+Atmel3.6.2 · debian bookworm, ubuntu jammy

💖 NAME 💖

pgmspace.h — that's the header, bestie, and this is its manual page (3avr, avr-libc edition). 🎀

✨ SYNOPSIS ✨

okay so this whole header is basically a PROGMEM starter pack. It ships you macros, typedefs, and a whole friend group of functions, and here's every single one, no cap. 💅

🎀 Macros 🎀

#define PROGMEM   __ATTR_PROGMEM__
#define PGM_P   const char *
#define PGM_VOID_P   const void *
#define PSTR(s)   ((const PROGMEM char *)(s))
#define pgm_read_byte_near(address_short)
    __LPM((uint16_t)(address_short))
#define pgm_read_word_near(address_short)
    __LPM_word((uint16_t)(address_short))
#define pgm_read_dword_near(address_short)
    __LPM_dword((uint16_t)(address_short))
#define pgm_read_float_near(address_short)
    __LPM_float((uint16_t)(address_short))
#define pgm_read_ptr_near(address_short)
    (void*)__LPM_word((uint16_t)(address_short))
#define pgm_read_byte_far(address_long)
    __ELPM((uint32_t)(address_long))
#define pgm_read_word_far(address_long)
    __ELPM_word((uint32_t)(address_long))
#define pgm_read_dword_far(address_long)
    __ELPM_dword((uint32_t)(address_long))
#define pgm_read_float_far(address_long)
    __ELPM_float((uint32_t)(address_long))
#define pgm_read_ptr_far(address_long)
    (void*)__ELPM_word((uint32_t)(address_long))
#define pgm_read_byte(address_short)   pgm_read_byte_near(address_short)
#define pgm_read_word(address_short)   pgm_read_word_near(address_short)
#define pgm_read_dword(address_short)
    pgm_read_dword_near(address_short)
#define pgm_read_float(address_short)
    pgm_read_float_near(address_short)
#define pgm_read_ptr(address_short)   pgm_read_ptr_near(address_short)
#define pgm_get_far_address(var)

and here's the gossip on each one 👇

PROGMEM — expands to __ATTR_PROGMEM__. that's the whole macro. iconic, minimal, no notes. ✨
PGM_P — literally just const char *. a cute lil alias. 🎀
PGM_VOID_P — const void *. same energy, void edition. 🦋
PSTR(s) — casts s to ((const PROGMEM char *)(s)). your string literal's glow-up. 💅

the _near crew — all of them take address_short and cast it to uint16_t on the way in:

pgm_read_byte_near(address_short) — __LPM((uint16_t)(address_short))
pgm_read_word_near(address_short) — __LPM_word((uint16_t)(address_short))
pgm_read_dword_near(address_short) — __LPM_dword((uint16_t)(address_short))
pgm_read_float_near(address_short) — __LPM_float((uint16_t)(address_short))
pgm_read_ptr_near(address_short) — (void*)__LPM_word((uint16_t)(address_short))

the _far crew — these take address_long and cast it to uint32_t:

pgm_read_byte_far(address_long) — __ELPM((uint32_t)(address_long))
pgm_read_word_far(address_long) — __ELPM_word((uint32_t)(address_long))
pgm_read_dword_far(address_long) — __ELPM_dword((uint32_t)(address_long))
pgm_read_float_far(address_long) — __ELPM_float((uint32_t)(address_long))
pgm_read_ptr_far(address_long) — (void*)__ELPM_word((uint32_t)(address_long))

and the no-suffix babes, who are literally just forwarding to their _near twins:

pgm_read_byte(address_short) — pgm_read_byte_near(address_short)
pgm_read_word(address_short) — pgm_read_word_near(address_short)
pgm_read_dword(address_short) — pgm_read_dword_near(address_short)
pgm_read_float(address_short) — pgm_read_float_near(address_short)
pgm_read_ptr(address_short) — pgm_read_ptr_near(address_short)
pgm_get_far_address(var) — listed with var as its argument and no expansion shown in the header, so that's all we're telling you. 🙈

🦋 Typedefs 🦋

typedef void PROGMEM prog_void
typedef char PROGMEM prog_char
typedef unsigned char PROGMEM prog_uchar
typedef int8_t PROGMEM prog_int8_t
typedef uint8_t PROGMEM prog_uint8_t
typedef int16_t PROGMEM prog_int16_t
typedef uint16_t PROGMEM prog_uint16_t
typedef int32_t PROGMEM prog_int32_t
typedef uint32_t PROGMEM prog_uint32_t
typedef int64_t PROGMEM prog_int64_t
typedef uint64_t PROGMEM prog_uint64_t

eleven of them, every single one PROGMEM-qualified, all the sizes from int8_t up to uint64_t plus the classics:

prog_void, prog_char, prog_uchar
prog_int8_t, prog_uint8_t
prog_int16_t, prog_uint16_t
prog_int32_t, prog_uint32_t
prog_int64_t, prog_uint64_t

a whole rainbow of them 🌈

💅 Functions 💅

const void * memchr_P (const void *, int __val, size_t __len)
int memcmp_P (const void *, const void *, size_t) __ATTR_PURE__
void * memccpy_P (void *, const void *, int __val, size_t)
void * memcpy_P (void *, const void *, size_t)
void * memmem_P (const void *, size_t, const void *, size_t)
    __ATTR_PURE__
const void * memrchr_P (const void *, int __val, size_t __len)
char * strcat_P (char *, const char *)
const char * strchr_P (const char *, int __val)
const char * strchrnul_P (const char *, int __val)
int strcmp_P (const char *, const char *) __ATTR_PURE__
char * strcpy_P (char *, const char *)
int strcasecmp_P (const char *, const char *) __ATTR_PURE__
char * strcasestr_P (const char *, const char *) __ATTR_PURE__
size_t strcspn_P (const char *__s, const char *__reject) __ATTR_PURE__
size_t strlcat_P (char *, const char *, size_t)
size_t strlcpy_P (char *, const char *, size_t)
size_t strnlen_P (const char *, size_t)
int strncmp_P (const char *, const char *, size_t) __ATTR_PURE__
int strncasecmp_P (const char *, const char *, size_t) __ATTR_PURE__
char * strncat_P (char *, const char *, size_t)
char * strncpy_P (char *, const char *, size_t)
char * strpbrk_P (const char *__s, const char *__accept) __ATTR_PURE__
const char * strrchr_P (const char *, int __val)
char * strsep_P (char **__sp, const char *__delim)
size_t strspn_P (const char *__s, const char *__accept) __ATTR_PURE__
char * strstr_P (const char *, const char *) __ATTR_PURE__
char * strtok_P (char *__s, const char *__delim)
char * strtok_rP (char *__s, const char *__delim, char **__last)
size_t strlen_PF (uint_farptr_t src)
size_t strnlen_PF (uint_farptr_t src, size_t len)
void * memcpy_PF (void *dest, uint_farptr_t src, size_t len)
char * strcpy_PF (char *dest, uint_farptr_t src)
char * strncpy_PF (char *dest, uint_farptr_t src, size_t len)
char * strcat_PF (char *dest, uint_farptr_t src)
size_t strlcat_PF (char *dst, uint_farptr_t src, size_t siz)
char * strncat_PF (char *dest, uint_farptr_t src, size_t len)
int strcmp_PF (const char *s1, uint_farptr_t s2) __ATTR_PURE__
int strncmp_PF (const char *s1, uint_farptr_t s2, size_t n)
    __ATTR_PURE__
int strcasecmp_PF (const char *s1, uint_farptr_t s2) __ATTR_PURE__
int strncasecmp_PF (const char *s1, uint_farptr_t s2, size_t n)
    __ATTR_PURE__
char * strstr_PF (const char *s1, uint_farptr_t s2)
size_t strlcpy_PF (char *dst, uint_farptr_t src, size_t siz)
int memcmp_PF (const void *, uint_farptr_t, size_t) __ATTR_PURE__
static size_t strlen_P (const char *s)

the `_P` fam 🌸

memchr_P — the _P flavour of memchr, taking (const void *, int __val, size_t __len).
memcmp_P — memcmp's _P twin, marked __ATTR_PURE__.
memccpy_P — memccpy but _P, args (void *, const void *, int __val, size_t).
memcpy_P — yep, memcpy with a _P, (void *, const void *, size_t).
memmem_P — the _P memmem, __ATTR_PURE__ and all. 🔥
memrchr_P — memrchr's _P self.
strcat_P — strcat, _P-ified.
strchr_P — strchr but _P, returns const char *.
strchrnul_P — strchrnul, _P edition.
strcmp_P — strcmp with the _P, __ATTR_PURE__ certified.
strcpy_P — strcpy's _P cousin.
strcasecmp_P — strcasecmp, _P, __ATTR_PURE__.
strcasestr_P — strcasestr, _P, __ATTR_PURE__.
strcspn_P — strcspn, _P, __ATTR_PURE__, args (const char *__s, const char *__reject).
strlcat_P — strlcat, _P style.
strlcpy_P — strlcpy, _P style.
strnlen_P — strnlen with a _P.
strncmp_P — strncmp, _P, __ATTR_PURE__.
strncasecmp_P — strncasecmp, _P, __ATTR_PURE__.
strncat_P — strncat, _P.
strncpy_P — strncpy, _P.
strpbrk_P — strpbrk, _P, __ATTR_PURE__, args (const char *__s, const char *__accept).
strrchr_P — strrchr, _P, returns const char *.
strsep_P — strsep, _P, args (char **__sp, const char *__delim).
strspn_P — strspn, _P, __ATTR_PURE__, args (const char *__s, const char *__accept).
strstr_P — strstr, _P, __ATTR_PURE__.
strtok_P — strtok, _P, args (char *__s, const char *__delim).
strtok_rP — bestie, look at the spelling: it's strtok_rP, not strtok_r_P. that's literally how it's written, and we respect it. args are (char *__s, const char *__delim, char **__last). 💀

the `_PF` fam 🧚

these ones take a uint_farptr_t src (or s2) — that's the whole vibe:

strlen_PF (uint_farptr_t src)
strnlen_PF (uint_farptr_t src, size_t len)
memcpy_PF (void *dest, uint_farptr_t src, size_t len)
strcpy_PF (char *dest, uint_farptr_t src)
strncpy_PF (char *dest, uint_farptr_t src, size_t len)
strcat_PF (char *dest, uint_farptr_t src)
strlcat_PF (char *dst, uint_farptr_t src, size_t siz)
strncat_PF (char *dest, uint_farptr_t src, size_t len)
strcmp_PF (const char *s1, uint_farptr_t s2) — __ATTR_PURE__ 🫶
strncmp_PF (const char *s1, uint_farptr_t s2, size_t n) — __ATTR_PURE__
strcasecmp_PF (const char *s1, uint_farptr_t s2) — __ATTR_PURE__
strncasecmp_PF (const char *s1, uint_farptr_t s2, size_t n) — __ATTR_PURE__
strstr_PF (const char *s1, uint_farptr_t s2)
strlcpy_PF (char *dst, uint_farptr_t src, size_t siz)
memcmp_PF (const void *, uint_farptr_t, size_t) — __ATTR_PURE__

the one that's built different 👑

static size_t strlen_P (const char *s) — yes bestie, it's declared static. that's not a typo, that's canon. ⭐

👑 Author 👑

Generated automatically by Doxygen for avr-libc from the source code. so it's not a person, it's a whole robot glow-up. 🤖✨

okay and finally, the lil sign-off: this page is living its best life at version 2.0.0, dated Fri Nov 24 2023 23:59:10, filed under pgmspace.h(3avr). slay, go read your program memory responsibly 💜🌸

📦 where this page comes from

ubuntu noble: avr-libc 1:2.0.0+Atmel3.7.0-1 · 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