NAME
tanh(), tanhf(), tanhl(), tanhw(), tanhq() — hyperbolic tangent functions
SYNOPSIS
#include <math.h>
double tanh(double x);
float tanhf(float x);
Itanium(R)-based System Only
long double tanhl(long double x);
extended tanhw(extended x);
quad tanhq(quad x);
DESCRIPTION
tanh()
returns the hyperbolic tangent of
x.
tanhf()
is a
float
version of
tanh();
it takes a
float
argument and returns a
float
result.
Itanium-based System Only
tanhl()
is a
long double
version of
tanh();
it takes a
long double
argument and returns a
long double
result.
tanhw()
is an
extended
version of
tanh();
it takes an
extended
argument and returns an
extended
result.
tanhq()
is equivalent to
tanhl()
on HP-UX systems.
USAGE
To use these functions, compile either with the default
-Ae
option or with the
-Aa
and the
-D_HPUX_SOURCE
options.
To use (for Itanium-based systems)
tanhw()
or
tanhq(),
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
tanh(±0)
returns ±0.
If
x
is ±INFINITY,
tanh()
returns ±1.0 respectively.
If
x
is NaN,
tanh()
returns NaN.
Whether
tanh()
raises the
inexact exception is unspecified.
ERRORS
No errors are defined.
STANDARDS CONFORMANCE
tanh()
: SVID3, XPG4.2, ANSI C, ISO/IEC C99
(including Annex F, ``IEC 60559 floating-point arithmetic'')
tanhf(),
tanhl()
: ISO/IEC C99 (including Annex F, ``IEC 60559 floating-point arithmetic'')
