#6798: fix wrong docs for the arguments to several trace events.
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.