1#include "complex_impl.h"
 2
 3/* acosh(z) = i acos(z) */
 4
 5double complex cacosh(double complex z)
 6{
 7	int zineg = signbit(cimag(z));
 8
 9	z = cacos(z);
10	if (zineg) return CMPLX(cimag(z), -creal(z));
11	else       return CMPLX(-cimag(z), creal(z));
12}