функция обратного гиперболического тангенса (inverse hyperbolic tangent function)
Имя (Name)
atanh, atanhf, atanhl - inverse hyperbolic tangent function
Синопсис (Synopsis)
#include <math.h>
double atanh(double x);
float atanhf(float x);
long double atanhl(long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
atanh():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| _XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
atanhf(), atanhl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
Описание (Description)
These functions calculate the inverse hyperbolic tangent of x;
that is the value whose hyperbolic tangent is x.
Возвращаемое значение (Return value)
On success, these functions return the inverse hyperbolic tangent
of x.
If x is a NaN, a NaN is returned.
If x is +0 (-0), +0 (-0) is returned.
If x is +1 or -1, a pole error occurs, and the functions return
HUGE_VAL, HUGE_VALF, or HUGE_VALL, respectively, with the
mathematically correct sign.
If the absolute value of x is greater than 1, a domain error
occurs, and a NaN is returned.
Ошибки (Error)
See math_error(7) for information on how to determine whether an
error has occurred when calling these functions.
The following errors can occur:
Domain error: x less than -1 or greater than +1
errno is set to EDOM. An invalid floating-point exception
(FE_INVALID) is raised.
Pole error: x is +1 or -1
errno is set to ERANGE (but see BUGS). A divide-by-zero
floating-point exception (FE_DIVBYZERO) is raised.
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│atanh(), atanhf(), atanhl() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘
Стандарты (Conforming to)
C99, POSIX.1-2001, POSIX.1-2008.
The variant returning double also conforms to SVr4, 4.3BSD.
Ошибки (баги) (Bugs)
In glibc 2.9 and earlier, when a pole error occurs, errno is set
to EDOM instead of the POSIX-mandated ERANGE. Since version
2.10, glibc does the right thing.
Смотри также (See also)
acosh(3), asinh(3), catanh(3), cosh(3), sinh(3), tanh(3)
