creal(3)

💖 creal(3) — the get-the-real-part girlies 💖

okay bestie, welcome to creal(3) from the Library Functions Manual ✨ this is the page for creal, crealf, and creall — the trio whose whole entire job is pulling the real part out of a complex number. iconic behavior honestly 🎀

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🌸 LIBRARY 🌸

it lives in the Math library, and you link it like this: libm, -lm. slay 💅

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✨ SYNOPSIS ✨

#include <complex.h>

double creal(double complex z);
float crealf(float complex z);
long double creall(long double complex z);

three functions, three flavours, one vibe 🦋

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💜 DESCRIPTION 💜

so like, these functions return the real part of the complex number z. that's it. that's the whole job. and they ate 💅

the way it works is, you always have this relationship:

z = creal(z) + I * cimag(z)

no cap, that's literally the definition of what parts make up z 🧚

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🎀 ATTRIBUTES 🎀

for the full rundown on what these terms even mean, go peek at attributes(7) 👑

• creal(), crealf(), creall() — Thread safety: MT-Safe 🌈

so yes bestie, they're thread safe, you can run them from multiple threads and it's giving totally fine 🫶

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👑 VERSIONS 👑

GCC also supports __real__. that one is a GNU extension — so it's a little extra, a little special, not standard ✨

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⭐ STANDARDS ⭐

C11, POSIX.1-2008. periodt 💖

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🌸 HISTORY 🌸

• glibc 2.1.
• C99, POSIX.1-2001.

the lore goes back a minute fr fr 📜

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🔥 SEE ALSO 🔥

• cabs(3)
• cimag(3)
• complex(7)

go read those next, they're all in the same friend group 🦋

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lowkey reminder bestie: creal isn't doing any magic, it's just handing you the real piece. if you wanted the imaginary part, that's cimag's department, don't @ me 😭

and that's the whole page!! this one is from Linux man-pages 6.20, dated 2026-02-08 — shoutout to the maintainers, mwah 💜 take care of yourself, hydrate, and go write some complex numbers 🎀✨🫶