bpo-29916: Include PyGetSetDef in C API extension documentation. (#831)
diff --git a/Doc/c-api/structures.rst b/Doc/c-api/structures.rst
index 67e4f9d..797b904 100644
--- a/Doc/c-api/structures.rst
+++ b/Doc/c-api/structures.rst
@@ -294,3 +294,43 @@
read-only access. Using :c:macro:`T_STRING` for :attr:`type` implies
:c:macro:`READONLY`. Only :c:macro:`T_OBJECT` and :c:macro:`T_OBJECT_EX`
members can be deleted. (They are set to *NULL*).
+
+
+.. c:type:: PyGetSetDef
+
+ Structure to define property-like access for a type. See also description of
+ the :c:member:`PyTypeObject.tp_getset` slot.
+
+ +-------------+------------------+-----------------------------------+
+ | Field | C Type | Meaning |
+ +=============+==================+===================================+
+ | name | const char \* | attribute name |
+ +-------------+------------------+-----------------------------------+
+ | get | getter | C Function to get the attribute |
+ +-------------+------------------+-----------------------------------+
+ | set | setter | optional C function to set or |
+ | | | delete the attribute, if omitted |
+ | | | the attribute is readonly |
+ +-------------+------------------+-----------------------------------+
+ | doc | const char \* | optional docstring |
+ +-------------+------------------+-----------------------------------+
+ | closure | void \* | optional function pointer, |
+ | | | providing additional data for |
+ | | | getter and setter |
+ +-------------+------------------+-----------------------------------+
+
+ The ``get`` function takes one :c:type:`PyObject\*` parameter (the
+ instance) and a function pointer (the associated ``closure``)::
+
+ typedef PyObject *(*getter)(PyObject *, void *);
+
+ It should return a new reference on success or *NULL* with a set exception
+ on failure.
+
+ ``set`` functions take two :c:type:`PyObject\*` parameters (the instance and
+ the value to be set) and a function pointer (the associated ``closure``)::
+
+ typedef int (*setter)(PyObject *, PyObject *, void *);
+
+ In case the attribute should be deleted the second parameter is *NULL*.
+ Should return ``0`` on success or ``-1`` with a set exception on failure.