NAME

cacosh, cacoshf, cacoshl — complex arc hyperbolic cosine functions

SYNOPSIS

#include <complex.h>

double complex cacosh(double complex z);
float complex cacoshf(float complex z);
long double complex cacoshl(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 cosine of z, with a branch cut at values less than 1 along the real axis.

RETURN VALUE

These functions shall return the complex arc hyperbolic cosine value, in the range of a half-strip of non-negative values along the real axis and in the interval [-iℼ, +iℼ] along the imaginary axis.

^[MXC] cacosh(conj(z)), cacoshf(conjf(z)), and cacoshl(conjl(z)) shall return exactly the same value as conj(cacosh(z)), conjf(cacoshf(z)), and conjl(cacoshl(z)), respectively, including for the special values of z below.

If z is ±0 + i0, +0 + iℼ/2 shall be returned.

If z is x + iInf where x is finite, +Inf + iℼ/2 shall be returned.

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

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, +Inf + iℼ shall be returned.

If z is +Inf + iy where y is positive-signed and finite, +Inf + i0 shall be returned.

If z is -Inf + iInf, +Inf + i3ℼ/4 shall be returned.

If z is +Inf + iInf, +Inf + iℼ/4 shall be returned.

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

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

ccosh

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.