NAME
atanh,
atanhf,
atanhl
—
inverse hyperbolic tangent function
LIBRARY
Math Library (libm, -lm)
SYNOPSIS
#include <math.h>
double
atanh(
double
x);
float
atanhf(
float
x);
long double
atanhl(
long
double x);
DESCRIPTION
The
atanh(),
atanhf(), and
atanhl() functions compute the inverse hyperbolic tangent of
the real argument
x.
RETURN VALUES
If |x|≥1,
atanh(
x),
atanhf(
x), and
atanhl(
x) return +inf, -inf or NaN,
and sets the global variable
errno to EDOM.
SEE ALSO
acosh(3),
asinh(3),
exp(3),
math(3)
STANDARDS
The
atanh() function conforms to
ISO/IEC
9899:1999 (“ISO C99”).
HISTORY
The
atanh() function appeared in
4.3BSD.