Ruby  3.1.4p223 (2023-03-30 revision HEAD)
cbrt.c
1 #include "ruby/missing.h"
2 #include <math.h>
3 
4 double cbrt(double x)
5 {
6  if (x < 0)
7  return -pow(-x, 1/3.0);
8  else
9  return pow(x, 1/3.0);
10 }
11