Computes the inverse hyperbolic tangent.
#include <math.h> float atanhf (x) float x; long double atanhl (x) long double x; double atanh (x) double x;
The atanhf, atanhl, and atanh subroutines compute the inverse hyperbolic tangent of the x parameter.
An application wishing to check for error situations should set the errno global variable to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if errno is nonzero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is nonzero, an error has occurred.
| x | Specifies the value to be computed. |
Upon successful completion, the atanhf, atanhl, and atanh subroutines return the inverse hyperbolic tangent of the given argument.
If x is ±1, a pole error occurs, and atanhf, atanhl , and atanh return the value of the macro HUGE_VALF, HUGE_VALL, and HUGE_VAL respectively, with the same sign as the correct value of the function.
For finite |x|>1, a domain error occurs, and a NaN is returned.
If x is NaN, a NaN is returned.
If x is 0, x is returned.
If x is ±Inf, a domain error shall occur, and a NaN is returned.
If x is subnormal, a range error may occur and x is returned.
The atanhf, atanhl, and atanh subroutines return NaNQ and set errno to EDOM if the absolute value of x is greater than 1.
math.h in AIX 5L Version 5.2 Files Reference.
Subroutines Overview in AIX 5L Version 5.2 General Programming Concepts: Writing and Debugging Programs.