bpo-36760: Clarify subprocess capture_output docs. (GH-13322)
Clarify how to capture stdout and stderr combined into one stream.
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index 3280c95..d840b46 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -55,7 +55,9 @@
If *capture_output* is true, stdout and stderr will be captured.
When used, the internal :class:`Popen` object is automatically created with
``stdout=PIPE`` and ``stderr=PIPE``. The *stdout* and *stderr* arguments may
- not be supplied at the same time as *capture_output*.
+ not be supplied at the same time as *capture_output*. If you wish to capture
+ and combine both streams into one, use ``stdout=PIPE`` and ``stderr=STDOUT``
+ instead of *capture_output*.
The *timeout* argument is passed to :meth:`Popen.communicate`. If the timeout
expires, the child process will be killed and waited for. The