opensolaris man page for atanhf

atanh(3M)						  Mathematical Library Functions						 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(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO
       feclearexcept(3M), fetestexcept(3M), math.h(3HEAD), matherr(3M), tanh(3M), attributes(5), standards(5)

SunOS 5.11							    12 Jul 2006 							 atanh(3M)