cbrt

float       cbrtf( float arg );

double      cbrt( double arg );

long double cbrtl( long double arg );

#define cbrt( arg )

Parameters

Return value

If no errors occur, the cubic root of arg (3√arg), is returned.

If a range error occurs due to underflow, the correct result (after rounding) is returned.

Error handling

Errors are reported as specified in math_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

• if the argument is ±0 or ±∞, it is returned, unchanged
• if the argument is NaN, NaN is returned.

Notes

cbrt(arg) is not equivalent to pow(arg, 1.0/3) because pow cannot raise a negative base to a fractional exponent.

Example

#include <stdio.h>
#include <math.h>
 
int main(void)
{
    // normal use
    printf("cbrt(729) = %f\n", cbrt(729));
    printf("cbrt(-0.125) = %f\n", cbrt(-0.125));
    // special values
    printf("cbrt(-0) = %f\n", cbrt(-0.0));
    printf("cbrt(+inf) = %f\n", cbrt(INFINITY));
}

cbrt(729) = 9.000000
cbrt(-0.125) = -0.500000
cbrt(-0) = -0.000000
cbrt(+inf) = inf

References

• C11 standard (ISO/IEC 9899:2011):
  • 7.12.7.1 The cbrt functions (p: 247)
  • 7.25 Type-generic math <tgmath.h> (p: 373-375)
  • F.10.4.1 The cbrt functions (p: 524)
• C99 standard (ISO/IEC 9899:1999):
  • 7.12.7.1 The cbrt functions (p: 228)
  • 7.22 Type-generic math <tgmath.h> (p: 335-337)
  • F.9.4.1 The cbrt functions (p: 460)

See also