Issue #13522: document error return values of some float and complex C API functions.
diff --git a/Doc/c-api/complex.rst b/Doc/c-api/complex.rst
index 364ab78..f5304bd 100644
--- a/Doc/c-api/complex.rst
+++ b/Doc/c-api/complex.rst
@@ -63,12 +63,18 @@
Return the quotient of two complex numbers, using the C :ctype:`Py_complex`
representation.
+ If *divisor* is null, this method returns zero and sets
+ :cdata:`errno` to :cdata:`EDOM`.
+
.. cfunction:: Py_complex _Py_c_pow(Py_complex num, Py_complex exp)
Return the exponentiation of *num* by *exp*, using the C :ctype:`Py_complex`
representation.
+ If :attr:`exp.imag` is not null, or :attr:`exp.real` is negative,
+ this method returns zero and sets :cdata:`errno` to :cdata:`EDOM`.
+
Complex Numbers as Python Objects
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -125,6 +131,7 @@
.. cfunction:: Py_complex PyComplex_AsCComplex(PyObject *op)
Return the :ctype:`Py_complex` value of the complex number *op*.
+ Upon failure, this method returns ``-1.0`` as a real value.
.. versionchanged:: 2.6
If *op* is not a Python complex number object but has a :meth:`__complex__`