double cbrt(double x);
long double cbrtl(long doublex);
These functions shall compute the real cube root of their argument
Upon successful completion, these functions shall return the cube
root of x.
x is NaN, a NaN shall be returned.
If x is ±0 or ±Inf, x shall be returned.
No errors are defined.
The following sections are informative.
For some applications, a true cube root function, which returns negative
results for negative arguments, is more appropriate
than pow( x, 1.0/3.0), which returns a NaN for x
less than 0.
The Base Definitions volume of IEEE Std 1003.1-2001, <math.h>
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at