Compute the complex inverse hyperbolic cosine
#include <complex.h> double complex cacosh( double complex z ); float complex cacoshf( float complex z ); long double complex cacoshl( long double complex z );
These functions compute the complex inverse hyperbolic cosine of z, with a branch cut at values less than 1 along the real axis.
To check for error situations, use feclearexcept() and fetestexcept(). For example:
The complex inverse hyperbolic cosine of z in the interval [0; Inf) along the real axis and in the interval [−iπ; +iπ] along the imaginary axis.
| If z is: | These functions return: | Errors: |
|---|---|---|
| ±0 + 0i | 0 + (π/2)i | — |
| x + Infi, for any finite x | Inf + (π/2)i | — |
| x + NaNi, for any nonzero finite x | NaN + NaNi | — |
| 0 + NaNi | NaN + NaNi | — |
| -Inf + yi, for any positive finite y | Inf + πi | — |
| -Inf - yi, for any positive finite y | Inf - πi | — |
| -Inf + Infi | Inf + (3π/4)i | — |
| ±Inf + NaNi | Inf + NaNi | — |
| NaN + yi, for any finite y | NaN + NaNi | — |
| NaN + Infi | Inf + NaNi | — |
| NaN + NaNi | NaN + NaNi | — |
These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.
| Safety: | |
|---|---|
| Cancellation point | No |
| Interrupt handler | No |
| Signal handler | No |
| Thread | Yes |