github.com/afumu/libc@v0.0.6/musl/src/complex/cacos.c (about)

     1  #include "complex_impl.h"
     2  
     3  // FIXME: Hull et al. "Implementing the complex arcsine and arccosine functions using exception handling" 1997
     4  
     5  /* acos(z) = pi/2 - asin(z) */
     6  
     7  double complex cacos(double complex z)
     8  {
     9  	z = casin(z);
    10  	return CMPLX(M_PI_2 - creal(z), -cimag(z));
    11  }