intmax_t(3type)

✨ intmax_t — the greatest-width basic integer types, bestie ✨

okay so real talk, this is from the intmax_t(3type) manual page and it's about the BIGGEST integer types C will give you. like, the widest ones. the main characters of integers. 💅

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🫶 NAME

intmax_t, uintmax_t — greatest-width basic integer types 🎀

📚 LIBRARY

Standard C library (libc)

🦋 SYNOPSIS

#include <stdint.h>

typedef /* ... */ intmax_t;
typedef /* ... */ uintmax_t;

#define INTMAX_WIDTH  /* ... */
#define UINTMAX_WIDTH INTMAX_WIDTH

#define INTMAX_MAX    /*  2**(INTMAX_WIDTH - 1) - 1  */
#define INTMAX_MIN    /*  - 2**(INTMAX_WIDTH - 1)    */
#define UINTMAX_MAX   /*  2**UINTMAX_WIDTH - 1       */

#define INTMAX_C(c)   c ## /* ... */
#define UINTMAX_C(c)  c ## /* ... */

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🌸 DESCRIPTION

okay so intmax_t is a signed integer type that can hold literally any value of any basic signed integer type your implementation supports. the range? it's giving [INTMAX_MIN, INTMAX_MAX]. 💖

uintmax_t is the unsigned sibling — an unsigned integer type that can hold literally any value of any basic unsigned integer type your implementation supports. its range is [0, UINTMAX_MAX]. bestie keeps it non-negative, no cap. ✨

The macros [U]INTMAX_WIDTH expand to the width in bits of these types. (yes, the [U] means "with or without the U", iykyk 🧚)

The macros [U]INTMAX_MAX expand to the maximum value that these types can hold.

The macro INTMAX_MIN expands to the minimum value that intmax_t can hold.

The macros [U]INTMAX_C() expand their argument to an integer constant of type [u]intmax_t. 🎀

The length modifier for [u]intmax_t for the printf(3) and the scanf(3) families of functions is j; resulting commonly in %jd, %ji, %ju, or %jx for printing [u]intmax_t values. literally so easy to remember. j for "just use this one". 💅

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🌈 STANDARDS

C11, POSIX.1-2024. periodt. 👑

💜 HISTORY

C99, POSIX.1-2001. she's been iconic for a while. ⭐

🍓 NOTES

The following header also provides these types: <inttypes.h>. (so you got options, bestie 🫶)

💀 BUGS

These types may not be as large as extended integer types, such as __int128. 😭 like she's the widest basic type but the extended ones can absolutely eat her up. do not come for me, I'm just the messenger.

🌟 SEE ALSO

int64_t(3type), intptr_t(3type), printf(3), strtoimax(3)

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and that's the whole vibe check 💖 this page came from Linux man-pages 6.20, dated 2026-02-08 — go off, man-pages team, we love to see it. 🌸🦋🎀