INFINITY(3)

💖 INFINITY(3) 💖

okay bestie so this is a manpage from the Library Functions Manual, and it's literally about the floating-point constants: INFINITY, NAN, HUGE_VAL, HUGE_VALF, HUGE_VALL. yes that's five whole macros. we're eating good today. 🍓

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✨ NAME ✨

INFINITY, NAN, HUGE_VAL, HUGE_VALF, HUGE_VALL — floating-point constants 👑

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🌸 LIBRARY 🌸

Math library (libm) 🧮

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🦋 SYNOPSIS 🦋

#define _ISOC99_SOURCE      /* See feature_test_macros(7) */
#include <math.h>

INFINITY

NAN

HUGE_VAL
HUGE_VALF
HUGE_VALL

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💅 DESCRIPTION 💅

so basically. the macro INFINITY expands to a float constant that represents positive infinity. yes. infinity. the whole thing. no cap. ♾️

the macro NAN expands to a float constant representing a quiet NaN (when supported, okay, when supported 🙈). and a quiet NaN is a NaN — that's "not-a-number" — that does not raise exceptions when it's used in arithmetic. the opposite of that is a signaling NaN, which is the loud dramatic one. see IEC 60559:1989 for the full lore. 📚

the macros HUGE_VAL, HUGE_VALF, and HUGE_VALL expand to constants of types double, float, and long double respectively, and they represent a large positive value — possibly positive infinity. so like, "big" or "BIG big", whichever the implementation vibes with. 🔥

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👑 STANDARDS 👑

C11. periodt. 💖

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🌈 HISTORY 🌈

C99, bestie. that's when this whole thing showed up. 🫶

on a glibc system, the macro HUGE_VAL is always available, like the main character it is. but availability of the NAN macro can be tested using #ifdef NAN, and similarly for INFINITY, HUGE_VALF, and HUGE_VALL — you gotta vibe check them one by one, iykyk. 👀

they will be defined by <math.h> if _ISOC99_SOURCE or _GNU_SOURCE is defined, or if __STDC_VERSION__ is defined and has a value not less than 199901L. so many ways to get in, all valid. slay. ✨

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💜 SEE ALSO 💜

• fpclassify(3) — the classification bestie 🧚
• math_error(7) — when math goes wrong 💀

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remember, NAN = quiet, exceptions not raised. don't come for her, she's not here for drama. 😭

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mwah — this was pulled from Linux man-pages 6.20, dated 2026-02-08, and it's the INFINITY(3) page. love her, obsessed, bye bestie 💖🎀🦋