cbrt, cbrtf, cbrtl - cube root functions
double cbrt(double x);
float cbrtf(float x);
long double cbrtl(long double x);
[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2017 defers to the ISO C standard.
These functions shall compute the real cube root of their argument x.
Upon successful completion, these functions shall return the cube root of x.
[MX] If x is NaN, a NaN shall be returned.
If x is ±0 or ±Inf, x shall be returned.
No errors are defined.
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.
First released in Issue 4, Version 2.
Moved from X/OPEN UNIX extension to BASE.
The cbrt() function is no longer marked as an extension.
The cbrtf() and cbrtl() functions are added for alignment with the ISO/IEC 9899:1999 standard.
The DESCRIPTION, RETURN VALUE, ERRORS, and APPLICATION USAGE sections are revised to align with the ISO/IEC 9899:1999 standard.
IEC 60559:1989 standard floating-point extensions over the ISO/IEC 9899:1999 standard are marked.
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