Let the concurrency option be multi-valued. #484

2 files changed, 8 insertions, 2 deletions

diff --git a/doc/cmd.rst b/doc/cmd.rst
index 90e21057..27c83aac 100644
--- a/doc/cmd.rst
+++ b/doc/cmd.rst
@@ -108,6 +108,10 @@ Give it a value of ``multiprocessing``, ``thread``, ``greenlet``, ``eventlet``,
 or ``gevent``.  Values other than ``thread`` require the :ref:`C extension
 <install_extension>`.
 
+If you are using ``--concurrency=multiprocessing``, you must set other options
+in the configuration file.  Other options on the command line will not be
+passed to the other processes.
+
 .. _multiprocessing: https://docs.python.org/2/library/multiprocessing.html
 .. _greenlet: http://greenlet.readthedocs.org/en/latest/
 .. _gevent: http://www.gevent.org/
diff --git a/doc/config.rst b/doc/config.rst
index 7c1aeb2c..b149f4f6 100644
--- a/doc/config.rst
+++ b/doc/config.rst
@@ -107,8 +107,8 @@ to more than one command.
 ``cover_pylib`` (boolean, default False): whether to measure the Python
 standard library.
 
-``concurrency`` (string, default "thread"): the name of the concurrency library
-in use by the product code.  If your program uses `multiprocessing`_,
+``concurrency`` (multi-string, default "thread"): the name concurrency
+libraries in use by the product code.  If your program uses `multiprocessing`_,
 `gevent`_, `greenlet`_, or `eventlet`_, you must name that library in this
 option, or coverage.py will produce very wrong results.
 
@@ -117,6 +117,8 @@ option, or coverage.py will produce very wrong results.
 .. _gevent: http://www.gevent.org/
 .. _eventlet: http://eventlet.net/
 
+Before version 4.2, this option only accepted a single string.
+
 .. versionadded:: 4.0
 
 ``data_file`` (string, default ".coverage"): the name of the data file to use