osx man page for atanhl

ATANH(3)						   BSD Library Functions Manual 						  ATANH(3)

NAME
     atanh -- inverse hyperbolic tangent function

SYNOPSIS
     #include <math.h>

     double
     atanh(double x);

     long double
     atanhl(long double x);

     float
     atanhf(float x);

DESCRIPTION
     The atanh() function computes the inverse hyperbolic tangent of the real argument x.

SPECIAL VALUES
     atanh(+-0) returns +-0.

     atanh(+-1) returns +-infinity and raises the "divide-by-zero" floating-point exception.

     atanh(x) returns a NaN and raises the "invalid" floating-point exception for |x| > 1.

VECTOR OPERATIONS
     If you need to apply the atanh() function to SIMD vectors or arrays, using the following functions provided by the Accelerate.framework may
     give significantly better performance:

     #include <Accelerate/Accelerate.h>

     vFloat vatanhf(vFloat x);
     void vvatanhf(float *y, const float *x, const int *n);
     void vvatanh(double *y, const double *x, const int *n);

SEE ALSO
     acosh(3), asinh(3), exp(3), math(3)

STANDARDS
     The atanh() function conforms to ISO/IEC 9899:2011.

4.3 Berkeley Distribution					 December 11, 2006					 4.3 Berkeley Distribution