Man Pages

atanh(3p) - phpMan atanh(3p) - phpMan

Command: man perldoc info search(apropos)  


ATANH(3P)                  POSIX Programmer's Manual                 ATANH(3P)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may dif-
       fer (consult the corresponding Linux manual page for details of Linux behavior), or the interface  may  not  be
       implemented on Linux.

NAME
       atanh, atanhf, atanhl - inverse hyperbolic tangent functions

SYNOPSIS
       #include <math.h>

       double atanh(double x);
       float atanhf(float x);
       long double atanhl(long double x);


DESCRIPTION
       These functions shall compute the inverse hyperbolic tangent of their argument x.

       An  application  wishing  to  check  for  error  situations  should  set  errno  to  zero  and  call feclearex-
       cept(FE_ALL_EXCEPT) before calling these functions.  On return, if errno is non-zero or fetestexcept(FE_INVALID
       | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.

RETURN VALUE
       Upon successful completion, these functions shall return the inverse hyperbolic tangent of their argument.

       If  x  is ?1, a pole error shall occur, and atanh(), atanhf(), and atanhl() shall 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 shall occur, and  either a NaN (if supported),  or  an  implementation-defined
       value shall be returned.

       If x is NaN, a NaN shall be returned.

       If x is ?0, x shall be returned.

       If  x  is ?Inf, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value
       shall be returned.

       If x is subnormal, a range error may occur and x should be returned.

ERRORS
       These functions shall 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_ERRNO) is non-zero, then errno shall be set  to  [EDOM].  If
       the  integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point excep-
       tion shall be raised.

       Pole Error
              The x argument is ?1.

       If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE].  If
       the  integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the divide-by-zero floating-point
       exception shall be raised.



       These functions may fail if:

       Range Error
              The value of x is subnormal.

       If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE].  If
       the  integer  expression  (math_errhandling  &  MATH_ERREXCEPT)  is non-zero, then the underflow floating-point
       exception shall be raised.


       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling & MATH_ERREXCEPT) are  indepen-
       dent of each other, but at least one of them must be non-zero.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       feclearexcept(),  fetestexcept(),  tanh(),  the  Base Definitions volume of IEEE Std 1003.1-2001, Section 4.18,
       Treatment of Error Conditions for Mathematical Functions, <math.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Stan-
       dard  for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifica-
       tions Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,  Inc  and  The
       Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Stan-
       dard, the original IEEE and The Open Group Standard is the referee  document.  The  original  Standard  can  be
       obtained online at http://www.opengroup.org/unix/online.html .



IEEE/The Open Group                  2003                            ATANH(3P)