exp2(3)

✨ exp2 — base-2 exponential function, but make it cute ✨

okay bestie, so this is the manual page for the math library girls — exp2, exp2f and exp2l 🎀 (that's the libm crew, link it with -lm 💅). It's giving "2 to the power of x" and honestly? iconic.

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🌸 NAME 🌸

exp2, exp2f, exp2l — the base-2 exponential function. that's the whole vibe 🦋

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💖 LIBRARY 💖

Math library (libm, -lm) — yes you gotta add the -lm, no cap, the compiler will literally ghost you otherwise 😭

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✨ SYNOPSIS ✨

#include <math.h>

double exp2(double x);
float exp2f(float x);
long double exp2l(long double x);

🧚 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

• exp2(), exp2f(), exp2l():

_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

bestie you need one of these defined or the functions just won't show up. gatekeeping fr 🙈

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🌈 DESCRIPTION 🌈

These functions return the value of 2 raised to the power of x. that's it. that's the function. 2^x, slay 💖

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⭐ RETURN VALUE ⭐

On success, these functions return the base-2 exponential value of x. so like, the answer. the moment. 👑

For various special cases — including the handling of infinity and NaN, as well as overflows and underflows — see exp(3). the special-case lore lives over there, go read it bestie, i'm not retyping all that 🫶

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💀 ERRORS 💀

See math_error(7) for information on how to determine whether an error has occurred when calling these functions. (tl;dr there's a whole system for checking and math_error(7) is the girl who explains it 🎀)

For a discussion of the errors that can occur for these functions, see exp(3). same deal — all the error discourse is in exp(3)'s house, not here 💅

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👑 ATTRIBUTES 👑

For an explanation of the terms used in this section, see attributes(7).

• exp2(), exp2f(), exp2l() — Thread safety: MT-Safe 🔥

so yeah, thread-safe, you can call these from wherever, it's fine, no drama, periodt ✨

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🎀 STANDARDS 🎀

C11, POSIX.1-2008. certified, stamped, official 🫶

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🌸 HISTORY 🌸

glibc 2.1. also C99, POSIX.1-2001. the glow-up timeline fr 📜✨

The variant returning double also conforms to SVr4, 4.3BSD. (that's exp2 specifically — it's been around, it has range 💜)

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🦋 SEE ALSO 🦋

• cbrt(3)
• cexp2(3)
• exp(3)
• exp10(3)
• sqrt(3)

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reminder bestie: exp2 is base 2, not base e. if you wanted e^x you want exp(3), don't mix them up or the math will be wrong and the vibes will be worse 😭💖

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okay that's the whole page 🎀 this was Linux man-pages 6.20, dated 2026-02-08, and it's exp2(3) if you're searching for it later. mwah, go compute something beautiful ✨💅🌈