cpp/numeric/complex/log

Computes complex of a complex value  with a branch cut along the negative real axis.

Return value
If no errors occur, the complex natural logarithm of is returned, in the range of a strip in the interval $[−iπ, +iπ]$ along the imaginary axis and mathematically unbounded along the real axis.

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

If the implementation supports IEEE floating-point arithmetic,
 * The function is continuous onto the branch cut taking into account the sign of imaginary part
 * If is, the result is  and fe_divbyzero is raised
 * If is, the result is  and fe_divbyzero is raised
 * If is  (for any finite x), the result is
 * If is  (for any finite x), the result is  and fe_invalid may be raised
 * If is  (for any finite positive y), the result is
 * If is  (for any finite positive y), the result is
 * If is, the result is
 * If is, the result is
 * If is, the result is
 * 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