cbrt(), cbrtf(), cbrtl()

Updated: May 06, 2022

Compute the cube root of a number

Synopsis:

#include <math.h>

double cbrt ( double x );

float cbrtf ( float x );

long double cbrtl ( long double x );

Arguments:

x
The number whose cube root you want to calculate.

Library:

libm
The general-purpose math library.
libm-sve
(QNX Neutrino 7.1 or later) A library that optimizes the code for ARMv8.2 chips that have Scalable Vector Extension hardware.

Your system requirements will determine how you should work with these libraries:

Note: Compile your program with the -fno-builtin option to prevent the compiler from using a built-in version of the function.

Description:

The cbrt(), cbrtf(), and cbrtl() functions compute the cube root of x.

To check for error situations, use feclearexcept() and fetestexcept(). For example:

Returns:

The cube root of x.

If x is: These functions return: Errors:
±0.0 x
±Inf x
NaN NaN

These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.

Examples:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main(int argc, char** argv) {
        double a, b;

        a = 27.0;
        b = cbrt(a);
        printf("The cube root of %f is %f \n", a, b);

        return(EXIT_SUCCESS);
}

produces the output:

The cube root of 27.000000 is 3.000000

Classification:

C11, POSIX 1003.1

Safety:  
Cancellation point No
Interrupt handler Yes
Signal handler Yes
Thread Yes