ATANH(3M) Mathematical Library Functions ATANH(3M)
atanh, atanhf, atanhl - inverse hyperbolic tangent functions
c99 [ flag... ] file... -lm [ library... ]
#include <math.h>
double atanh(double x);
float atanhf(float x);
long double atanhl(long double x);
These functions compute the inverse hyperbolic tangent of their
argument x.
Upon successful completion, these functions return the inverse
hyperbolic tangent of their argument.
If x is +-1, a pole error occurs and atanh(), atanhf(), and atanhl()
return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL,
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, NaN is returned.
If x is +0, x is returned.
If x is +Inf, a domain error occurs and a NaN is returned.
For exceptional cases, matherr(3M) tabulates the values to be
returned by atanh() as specified by SVID3 and XPG3.
These functions will fail if:
Domain Error
The x argument is finite and not in the range [-1,1],
or is +-Inf.
If the integer expression (math_errhandling &
MATH_ERREXCEPT) is non-zero, the invalid floating-
point exception is raised.
The atanh() function sets errno to EDOM if the
absolute value of x is greater than 1.0.
Pole Error
The x argument is +-1.
If the integer expression (math_errhandling &
MATH_ERREXCEPT) is non-zero, then the divide-by-zero
floating-point exception is raised.
The atanh() function sets errno to ERANGE if the
absolute value of x is equal to 1.0.
An application wanting to check for exceptions should call
feclearexcept(FE_ALL_EXCEPT) before calling these functions. On
return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW |
FE_UNDERFLOW) is non-zero, an exception has been raised. An
application should either examine the return value or check the
floating point exception flags to detect exceptions.
An application can also set errno to 0 before calling atanh(). On
return, if errno is non-zero, an error has occurred. The atanhf() and
atanhl() functions do not set errno.
See attributes(7) for descriptions of the following attributes:
+----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+----------------------------+-----------------------------+
|Interface Stability | Standard |
+----------------------------+-----------------------------+
|MT-Level | MT-Safe |
+----------------------------+-----------------------------+
math.h(3HEAD), feclearexcept(3M), fetestexcept(3M), matherr(3M),
tanh(3M), attributes(7), standards(7)
SunOS 5.11 July 12, 2006 ATANH(3M)
NAME
atanh, atanhf, atanhl - inverse hyperbolic tangent functions
SYNOPSIS
c99 [ flag... ] file... -lm [ library... ]
#include <math.h>
double atanh(double x);
float atanhf(float x);
long double atanhl(long double x);
DESCRIPTION
These functions compute the inverse hyperbolic tangent of their
argument x.
RETURN VALUES
Upon successful completion, these functions return the inverse
hyperbolic tangent of their argument.
If x is +-1, a pole error occurs and atanh(), atanhf(), and atanhl()
return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL,
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, NaN is returned.
If x is +0, x is returned.
If x is +Inf, a domain error occurs and a NaN is returned.
For exceptional cases, matherr(3M) tabulates the values to be
returned by atanh() as specified by SVID3 and XPG3.
ERRORS
These functions will fail if:
Domain Error
The x argument is finite and not in the range [-1,1],
or is +-Inf.
If the integer expression (math_errhandling &
MATH_ERREXCEPT) is non-zero, the invalid floating-
point exception is raised.
The atanh() function sets errno to EDOM if the
absolute value of x is greater than 1.0.
Pole Error
The x argument is +-1.
If the integer expression (math_errhandling &
MATH_ERREXCEPT) is non-zero, then the divide-by-zero
floating-point exception is raised.
The atanh() function sets errno to ERANGE if the
absolute value of x is equal to 1.0.
USAGE
An application wanting to check for exceptions should call
feclearexcept(FE_ALL_EXCEPT) before calling these functions. On
return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW |
FE_UNDERFLOW) is non-zero, an exception has been raised. An
application should either examine the return value or check the
floating point exception flags to detect exceptions.
An application can also set errno to 0 before calling atanh(). On
return, if errno is non-zero, an error has occurred. The atanhf() and
atanhl() functions do not set errno.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+----------------------------+-----------------------------+
|Interface Stability | Standard |
+----------------------------+-----------------------------+
|MT-Level | MT-Safe |
+----------------------------+-----------------------------+
SEE ALSO
math.h(3HEAD), feclearexcept(3M), fetestexcept(3M), matherr(3M),
tanh(3M), attributes(7), standards(7)
SunOS 5.11 July 12, 2006 ATANH(3M)