cbrt(3)

✨ cbrt(3) — the cube root girlies ✨

okay so bestie, welcome to cbrt(3), the manual page for the cube root function and its two glow-up siblings. this is the one you want when you need to undo a cube. no cap. 🧊

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🌸 NAME 🌸

cbrt, cbrtf, cbrtl — cube root function 💅

📚 LIBRARY 📚

Math library (libm, link it with -lm) 🫶

✨ SYNOPSIS ✨

#include <math.h>

double cbrt(double x);
float cbrtf(float x);
long double cbrtl(long double x);

🎀 Feature Test Macro Requirements for glibc 🎀

(peep feature_test_macros(7) if you wanna know what these even are, iykyk)

cbrt():

_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
    || _XOPEN_SOURCE >= 500
    || /* Since glibc 2.19: */ _DEFAULT_SOURCE
    || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

cbrtf(), cbrtl():

_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
    || /* Since glibc 2.19: */ _DEFAULT_SOURCE
    || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

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💖 DESCRIPTION 💖

These functions return the (real) cube root of x. that's it, that's the whole job. 🫧

and here's the thing that makes her so iconic: this function cannot fail. literally cannot. every representable real value has a real cube root, and rounding it to a representable value never causes overflow nor underflow. no edge case drama, no surprise L's, just vibes. 👑

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🌈 RETURN VALUE 🌈

These functions return the cube root of x. simple as.

and if x is +0, -0, positive infinity, negative infinity, or NaN? then x is returned. she's giving "i'm not doing extra work for this" and honestly? valid. 💀

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🦋 ERRORS 🦋

No errors occur. like, at all. zero. none. not even one. the error handling section is a ghost town and we love that for her. 🌵✨

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👑 ATTRIBUTES 👑

for an explanation of the terms used in this section, go check attributes(7). the girlies over there explain the lore.

• Interface: cbrt(), cbrtf(), cbrtl() — Attribute: Thread safety — Value: MT-Safe 🔥

so yes bestie, she's MT-Safe. thread away. 🧵

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⭐ STANDARDS ⭐

C11, POSIX.1-2008. certified and valid, periodt. 💅

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🌸 HISTORY 🌸

GNU, C99, POSIX.1-2001. she's been around, she's got lore. 🎀

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🔗 SEE ALSO 🔗

• pow(3)
• sqrt(3)

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that's the whole page bestie, go cube root something. ily 🫶

this has been Linux man-pages 6.20, dated 2026-02-08, coming at you with cbrt(3) energy. stay iconic. 💖✨