HP-UX Reference (11i v1 00/12) - 3 Library Functions A-M (vol 6)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man3/!!!intro.3c
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a
atanh(3M) atanh(3M)
NAME
atanh() - inverse hyperbolic tangent function
SYNOPSIS
#include <math.h>
double atanh(double x);
DESCRIPTION
The atanh() function computes the inverse hyperbolic tangent of its argument.
The ISO/ANSI C committee has approved the atanh() function for inclusion in the C9X draft standard.
To use this function, compile either with the default -Ae option or with the -Aa and -D_HPUX_SOURCE
options. Make sure your program includes <math.h>. Link in the math library by specifying -lm on the
compiler or linker command line.
RETURN VALUE
If x is NaN, atanh() returns NaN.
If |x| > 1.0, atanh() returns NaN and sets
errno to [EDOM].
If |x| = 1.0,
atanh() returns ±HUGE_VAL (according to the sign of x) and sets
errno to [ERANGE].
ERRORS
If
atanh() fails, errno is set to one of the following values.
[EDOM] x has an absolute value greater than 1.0.
[ERANGE] x has an absolute value equal to 1.0.
SEE ALSO
acosh(3M), asinh(3M),tanh(3M), math(5).
STANDARDS CONFORMANCE
atanh(): SVID3, XPG4.2
HP-UX Release 11i: December 2000 − 1 − Section 3−−29
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