Improve the abstract.

Author: ZeroIntensity

peps/pep-0788.rst

@@ -49,6 +49,40 @@ correct and safer replacement for :c:func:`PyGILState_Ensure` and
 
     PyThreadState_Release();
 
+This is achieved by introducing two concepts into the C API:
+
+-  "Daemon" and "non-daemon" threads, similar to how it works in the 
+   :mod:`threading` module.
+-  Interpreter reference counts which prevent the interpreter from finalizing.
+
+In :c:func:`PyThreadState_Ensure`, both of these ideas are applied. The
+calling thread is to store a reference to the interpreter via
+:c:func:`PyInterpreterState_Hold`. :c:func:`PyInterpreterState_Hold`
+increases the reference count of the interpreter, requiring the thread
+to finish (by eventually calling :c:func:`PyThreadState_Release`) before
+beginning finalization.
+
+As such, creating a native thread with this API would look something
+like this:
+
+.. code-block:: c
+
+    static PyObject *
+    my_method(PyObject *self, PyObject *unused)
+    {
+        PyThread_handle_t handle;
+        PyThead_indent_t indent;
+
+        PyInterpreterState *interp = PyInterpreterState_Hold();
+        if (PyThread_start_joinable_thread(thread_func, interp, &ident, &handle) < 0) {
+            PyInterpreterState_Release(interp);
+            return NULL;
+        }
+        /* The thread will always attach and finish, because we increased
+           the reference count of the interpreter. */
+        Py_RETURN_NONE;
+    }
+
 Motivation
 ==========