Added 'Introduction' section head and 'Memory Management' subsection.
diff --git a/Doc/extref.tex b/Doc/extref.tex
index 60940f5..183abd0 100644
--- a/Doc/extref.tex
+++ b/Doc/extref.tex
@@ -2,6 +2,8 @@
\chapter{Extension Reference}
+\section{Introduction}
+
From the viewpoint of of C access to Python services, we have:
\begin{enumerate}
@@ -13,7 +15,7 @@
to write a simple application that gets Python code from the user,
execs it, and returns the output or errors.
- \item "Abstract objects layer": which is the subject of this proposal.
+ \item "Abstract objects layer": which is the subject of this chapter.
It has many functions operating on objects, and lest you do many
things from C that you can also write in Python, without going
through the Python parser.
@@ -46,6 +48,23 @@
so new objects can be returned from C functions that otherwise treat
objects generically.
+\subsection{Memory Management}
+
+ For all of the functions described in this chapter, if a function
+ retains a reference to a Python object passed as an argument, then the
+ function will increase the reference count of the object. It is
+ unnecessary for the caller to increase the reference count of an
+ argument in anticipation of the object's retention.
+
+ All Python objects returned from functions should be treated as new
+ objects. Functions that return objects assume that the caller will
+ retain a reference and the reference count of the object has already
+ been incremented to account for this fact. A caller that does not
+ retain a reference to an object that is returned from a function
+ must decrement the reference count of the object (using
+ DECREF(object)) to prevent memory leaks.
+
+
\section{Object Protocol}
\begin{cfuncdesc}{int}{PyObject_Print}{PyObject *o, FILE *fp, int flags}