cbrtf
(3)cube root function
#include <math.h> double cbrt(double x); float cbrtf(float x); long double cbrtl(long double x); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): cbrt(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 500 || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE cbrtf(), cbrtl(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE