#include "complex_impl.h" // FIXME: Hull et al. "Implementing the complex arcsine and arccosine functions using exception handling" 1997 /* acos(z) = pi/2 - asin(z) */ double complex cacos(double complex z) { z = casin(z); return CMPLX(M_PI_2 - creal(z), -cimag(z)); }