posix man page for acoshf

ACOSH(P)						     POSIX Programmer's Manual							  ACOSH(P)

NAME
       acosh, acoshf, acoshl - inverse hyperbolic cosine functions

SYNOPSIS
       #include <math.h>

       double acosh(double x);
       float acoshf(float x);
       long double acoshl(long double x);

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

       An  application	wishing  to check for error situations should set errno to zero and call feclearexcept(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 cosine of their argument.

       For  finite  values  of	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 +1, +0 shall be returned.

       If x is +Inf, +Inf 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.

ERRORS
       These functions shall fail if:

       Domain Error
	      The x argument is finite and less than +1.0,    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 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 independent of each other, but at
       least one of them must be non-zero.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

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

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications 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 Standard, 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								  ACOSH(P)