carg(3)

✨ carg(3) ✨

okay bestie, welcome to the Linux Library Functions Manual 💖 you're here for carg, cargf, and cargl, and honestly? they're about to eat. no cap.

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🌸 NAME 🌸

carg, cargf, cargl — calculate the complex argument 💅

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🎀 LIBRARY 🎀

Math library (libm, -lm)

like, link it, obviously. -lm. don't forget. iykyk. 🫶

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✨ SYNOPSIS ✨

#include <complex.h>

double carg(double complex z);
float cargf(float complex z);
long double cargl(long double complex z);

three of them. one for each size of dramatic. double, float, long double. slay. 👑

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🦋 DESCRIPTION 🦋

so these functions calculate the complex argument of z — which, pro tip, is also called the phase angle — and there's a branch cut along the negative real axis, which is the drama of it all. 🌈

here's the vibe: a complex number can be described by two real coordinates, and you can pick your flavor.

flavor one: rectangular coordinates 🍓 and you get

z = x + I * y

where x = creal(z) and y = cimag(z).

flavor two: polar coordinates 🍓 and you get

z = r * cexp(I * a)

where r = cabs(z) is the "radius", the "modulus", literally the absolute value of z — and a = carg(z) is the "phase angle", the argument of z. it's giving main character energy for real. 🌟

and the way that these two relate?? 🫣

tan(carg(z)) = cimag(z) / creal(z)

periodt. 💅

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💖 RETURN VALUE 💖

the return value is in the range of [-pi,pi]. that's it, that's the tea. ☕ not me being precise about it.

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⭐ ATTRIBUTES ⭐

for an explanation of the terms used in this section, go look at attributes(7) — it's like the group chat glossary bestie, very helpful.

the girls are thread safe, no notes:

• carg(), cargf(), cargl() — Thread safety: MT-Safe 🔥

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👑 STANDARDS 👑

C11, POSIX.1-2008.

certified. iconic. 💜

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🌈 HISTORY 🌈

• glibc 2.1.
• C99, POSIX.1-2001.

so it's been around forever, a true veteran, a legend lowkey. 🙈

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🧚 SEE ALSO 🧚

• cabs(3)
• complex(7)

go read the friends, they're part of the same little universe bestie. 🦋

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k that's the whole page, go forth and compute your phase angles, i'm obsessed with you fr fr 💖

Linux man-pages 6.20 · 2026-02-08 — okay so that's the version and the date, clocked, timestamped, and it's giving official. bye bestie, love you, drink water! 🎀✨🫶