atanh(3m) [opensolaris man page]
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)
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ATANH(P) POSIX Programmer's Manual ATANH(P) 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 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 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 exception 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 independent 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 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 ATANH(P)