1 files changed, 24 insertions, 8 deletions
diff --git a/Doc/library/filecmp.rst b/Doc/library/filecmp.rst
index 8a88f8c..8471a72 100644
--- a/Doc/library/filecmp.rst
+++ b/Doc/library/filecmp.rst
@@ -27,6 +27,10 @@ The :mod:`filecmp` module defines the following functions:
    Note that no external programs are called from this function, giving it
    portability and efficiency.
 
+   This function uses a cache for past comparisons and the results,
+   with a cache invalidation mechanism relying on stale signatures
+   or by explicitly calling :func:`clear_cache`.
+
 
 .. function:: cmpfiles(dir1, dir2, common, shallow=True)
 
@@ -48,6 +52,15 @@ The :mod:`filecmp` module defines the following functions:
    one of the three returned lists.
 
 
+.. function:: clear_cache()
+
+   .. versionadded:: 3.4
+
+   Clear the filecmp cache. This may be useful if a file is compared so quickly
+   after it is modified that it is within the mtime resolution of
+   the underlying filesystem.
+
+
 .. _dircmp-objects:
 
 The :class:`dircmp` class
@@ -55,28 +68,25 @@ The :class:`dircmp` class
 
 .. class:: dircmp(a, b, ignore=None, hide=None)
 
-   Construct a new directory comparison object, to compare the directories *a* and
-   *b*. *ignore* is a list of names to ignore, and defaults to ``['RCS', 'CVS',
-   'tags']``. *hide* is a list of names to hide, and defaults to ``[os.curdir,
-   os.pardir]``.
+   Construct a new directory comparison object, to compare the directories *a*
+   and *b*.  *ignore* is a list of names to ignore, and defaults to
+   :attr:`filecmp.DEFAULT_IGNORES`.  *hide* is a list of names to hide, and
+   defaults to ``[os.curdir, os.pardir]``.
 
    The :class:`dircmp` class compares files by doing *shallow* comparisons
    as described for :func:`filecmp.cmp`.
 
    The :class:`dircmp` class provides the following methods:
 
-
    .. method:: report()
 
       Print (to :data:`sys.stdout`) a comparison between *a* and *b*.
 
-
    .. method:: report_partial_closure()
 
       Print a comparison between *a* and *b* and common immediate
       subdirectories.
 
-
    .. method:: report_full_closure()
 
       Print a comparison between *a* and *b* and common subdirectories
@@ -133,7 +143,7 @@ The :class:`dircmp` class
 
    .. attribute:: common_files
 
-      Files in both *a* and *b*
+      Files in both *a* and *b*.
 
 
    .. attribute:: common_funny
@@ -164,6 +174,12 @@ The :class:`dircmp` class
       A dictionary mapping names in :attr:`common_dirs` to :class:`dircmp`
       objects.
 
+.. attribute:: DEFAULT_IGNORES
+
+   .. versionadded:: 3.4
+
+   List of directories ignored by :class:`dircmp` by default.
+
 
 Here is a simplified example of using the ``subdirs`` attribute to search
 recursively through two directories to show common different files::