cpp/numeric/complex/acos

Computes complex arc cosine of a complex value. Branch cuts exist outside the interval $[−1, +1]$ along the real axis.

Return value
If no errors occur, complex arc cosine of is returned, in the range of a strip unbounded along the imaginary axis and in the interval $[0, +π]$ along the real axis.

Error handling and special values
Errors are reported consistent with math_errhandling.

If the implementation supports IEEE floating-point arithmetic,
 * If is, the result is
 * If is, the result is
 * If is  (for any finite x), the result is
 * If is  (for any nonzero finite x), the result is  and fe_invalid may be raised.
 * If is  (for any positive finite y), the result is
 * If is  (for any positive finite y), the result is
 * If is, the result is
 * If is, the result is
 * If is, the result is  (the sign of the imaginary part is unspecified)
 * If is  (for any finite y), the result is  and fe_invalid may be raised
 * If is, the result is
 * If is, the result is
 * If is, the result is