Fixed coerce docs
diff --git a/Doc/extref.tex b/Doc/extref.tex
index c88976c..75485c6 100644
--- a/Doc/extref.tex
+++ b/Doc/extref.tex
@@ -356,10 +356,18 @@
\begin{cfuncdesc}{PyObject*}{PyNumber_Coerce}{PyObject *o1, PyObject *o2}
- On success, returns a tuple containing \code{o1} and \code{o2} converted to
- a common numeric type, or None if no conversion is possible.
- Returns -1 on failure. This is equivalent to the Python
- expression: \code{coerce(o1,o2)}.
+ This function takes the addresses of two variables of type
+ \code{PyObject*}.
+
+ If the objects pointed to by \code{*p1} and \code{*p2} have the same type,
+ increment their reference count and return 0 (success).
+ If the objects can be converted to a common numeric type,
+ replace \code{*p1} and \code{*p2} by their converted value (with 'new'
+ reference counts), and return 0.
+ If no conversion is possible, or if some other error occurs,
+ return -1 (failure) and don't increment the reference counts.
+ The call \code{PyNumber_Coerce(&o1, &o2)} is equivalent to the Python
+ statement \code{o1, o2 = coerce(o1, o2)}.
\end{cfuncdesc}