NAME

catanh, catanhf, catanhl — complex arc hyperbolic tangent functions

SYNOPSIS

#include <complex.h>

double complex catanh(double complex z);
float complex catanhf(float complex z);
long double complex catanhl(long double complex z);


DESCRIPTION

^[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2024 defers to the ISO C standard.

These functions shall compute the complex arc hyperbolic tangent of z, with branch cuts outside the interval [-1, +1] along the real axis.

RETURN VALUE

These functions shall return the complex arc hyperbolic tangent value, in the range of a strip mathematically unbounded along the real axis and in the interval [-iℼ/2, +iℼ/2] along the imaginary axis.

^[MXC] catanh(conj(z)), catanhf(conjf(z)), and catanhl(conjl(z)) shall return exactly the same value as conj(catanh(z)), conjf(catanhf(z)), and conjl(catanhl(z)), respectively, and catanh(-z), catanhf(-z), and catanhl(-z) shall return exactly the same value as -catanh(z), -catanhf(z), and -catanhl(z), respectively, including for the special values of z below.

If z is +0 + i0, +0 + i0 shall be returned.

If z is +0 + iNaN, +0 + iNaN shall be returned.

If z is +1 + i0, +Inf + i0 shall be returned and the divide-by-zero floating-point exception shall be raised.

If z is x + iInf where x is positive-signed and finite, +0 + iℼ/2 shall be returned.

If z is x + iNaN where x is non-zero and finite, NaN + iNaN shall be returned and the invalid floating-point exception may be raised.

If z is +Inf + iy where y is positive-signed and finite, +0 + iℼ/2 shall be returned.

If z is +Inf + iInf, +0 + iℼ/2 shall be returned.

If z is +Inf + iNaN, +0 + iNaN shall be returned.

If z is NaN + iy where y is finite, NaN + iNaN shall be returned and the invalid floating-point exception may be raised.

If z is NaN + iInf, ±0 + iℼ/2 shall be returned; the sign of the real part of the result is unspecified.

If z is NaN + iNaN, NaN + iNaN shall be returned.

ERRORS

No errors are defined.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

ctanh

XBD <complex.h>

CHANGE HISTORY

First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.

Issue 8

Austin Group Defect 1302 is applied, aligning these functions with the ISO/IEC 9899:2018 standard.