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 [- i ℼ, + i ℼ] 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 + i 0, +0 + i ℼ/2 shall be returned.
If z is x + i Inf where x is finite, +Inf + i ℼ/2 shall be returned.
If z is 0 + i NaN, NaN ± i ℼ/2 shall be returned; the sign of the imaginary part of the result is unspecified.
If z is x + i NaN where x is non-zero and finite, NaN + i NaN 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 + i ℼ shall be returned.
If z is +Inf + iy where y is positive-signed and finite, +Inf + i 0 shall be returned.
If z is -Inf + i Inf, +Inf + i 3ℼ/4 shall be returned.
If z is +Inf + i Inf, +Inf + i ℼ/4 shall be returned.
If z is ±Inf + i NaN, +Inf + i NaN shall be returned.
If z is NaN + iy where y is finite, NaN + i NaN shall be returned and the invalid floating-point exception may be raised.
If z is NaN + i Inf, +Inf + i NaN shall be returned.
If z is NaN + i NaN, NaN + i NaN shall be returned.
ERRORS
No errors are defined.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
XBD <complex.h>
CHANGE HISTORY
First released in Issue 6. Derived from the ISO/IEC 9899:1999 (“ISO C99”) standard.
Issue 8
Austin Group Defect 1302 is applied, aligning these functions with the ISO/IEC 9899:2018 standard.