diff --git a/Doc/c-api/init.rst b/Doc/c-api/init.rst
index 031e322..1c62155 100644
--- a/Doc/c-api/init.rst
+++ b/Doc/c-api/init.rst
@@ -929,13 +929,14 @@
    +------------------------------+--------------------------------------+
    | :const:`PyTrace_LINE`        | Always *NULL*.                       |
    +------------------------------+--------------------------------------+
-   | :const:`PyTrace_RETURN`      | Value being returned to the caller.  |
+   | :const:`PyTrace_RETURN`      | Value being returned to the caller,  |
+   |                              | or *NULL* if caused by an exception. |
    +------------------------------+--------------------------------------+
-   | :const:`PyTrace_C_CALL`      | Name of function being called.       |
+   | :const:`PyTrace_C_CALL`      | Function object being called.        |
    +------------------------------+--------------------------------------+
-   | :const:`PyTrace_C_EXCEPTION` | Always *NULL*.                       |
+   | :const:`PyTrace_C_EXCEPTION` | Function object being called.        |
    +------------------------------+--------------------------------------+
-   | :const:`PyTrace_C_RETURN`    | Always *NULL*.                       |
+   | :const:`PyTrace_C_RETURN`    | Function object being called.        |
    +------------------------------+--------------------------------------+
 
 
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 352eb62..0f35b8b 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -806,8 +806,9 @@
 
    ``'return'``
       A function (or other code block) is about to return.  The local trace
-      function is called; *arg* is the value that will be returned.  The trace
-      function's return value is ignored.
+      function is called; *arg* is the value that will be returned, or ``None``
+      if the event is caused by an exception being raised.  The trace function's
+      return value is ignored.
 
    ``'exception'``
       An exception has occurred.  The local trace function is called; *arg* is a
@@ -819,10 +820,10 @@
       a built-in.  *arg* is the C function object.
 
    ``'c_return'``
-      A C function has returned. *arg* is ``None``.
+      A C function has returned. *arg* is the C function object.
 
    ``'c_exception'``
-      A C function has raised an exception.  *arg* is ``None``.
+      A C function has raised an exception.  *arg* is the C function object.
 
    Note that as an exception is propagated down the chain of callers, an
    ``'exception'`` event is generated at each level.