HP-UX Reference (11i v2 04/09) - 3 Library Functions A-M (vol 6)
a
atanh(3M) atanh(3M)
NAME
atanh( ), atanhf( ), atanhl( ), atanhw( ), atanhq( ) - arc hyperbolic tangent functions
SYNOPSIS
#include <math.h>
double atanh(double x);
Itanium(R)-based System Only
float atanhf(float x);
long double atanhl(long double x);
extended atanhw(extended x);
quad atanhq(quad x);
DESCRIPTION
atanh() returns the arc hyperbolic tangent of x.
Itanium-based System Only
atanhf() is a float version of atanh(); it takes a
float argument and returns a float result.
atanhl() is a long double version of atanh(); it takes a long double argument and returns a
long double result.
atanhw() is an extended version of atanh(); it takes an extended argument and returns an
extended result.
atanhq() is equivalent to atanhl() on HP-UX systems.
USAGE
To use (for Itanium-based systems)
atanhf(), atanhl(), atanhw(),oratanhq(), compile either
with the default
-Ae option or with the -Aa and -D_HPUX_SOURCE
options.
To use (for Itanium-based systems)
atanhw() or atanhq(), compile also with the -fpwidetypes
option.
To use any of these functions, make sure your program includes
<math.h>, and link in the math library
by specifying -lm on the compiler or linker command line.
For more information, see the HP-UX Floating-Point Guide.
RETURN VALUE
atanh(±0) returns ±0.
atanh(±1) returns ±Inf and raises the divide-by-zero floating-point exception.
If |x| > 1.0,
atanh() returns NaN and raises the invalid exception.
If x is NaN,
atanh() returns NaN.
When it raises no other exception, whether
atanh() raises the inexact exception is unspecified.
ERRORS
If |x| > 1.0,
atanh() sets errno to [EDOM].
Itanium-based System Only
HP-UX
libm functions on Itanium-based system do not set errno by default. For errno setting, com-
pile with the +Olibmerrno option.
SEE ALSO
acosh(3M), asinh(3M), catanh(3M), tanh(3M), math(5).
STANDARDS CONFORMANCE
atanh(), atanhf(), atanhl() : ISO/IEC C99 (including Annex F, ‘‘IEC 60559 floating-point arith-
metic’’)
Section 3−−46 Hewlett-Packard Company − 1 − HP-UX 11i Version 2: September 2004