extend cmath (some of the functions are dummy)

[libm] / src / cmath / catanh.c

#include "libm.h"

/* atanh = -i atan(i z) */

double complex catanh(double complex z)
{
        z = catan(cpack(-cimag(z), creal(z)));
        return cpack(cimag(z), -creal(z));
}