Mention VMSError

pep-3151.txt

@@ -48,6 +48,7 @@ of classes, arranged in the following sub-hierarchies::
             +-- io.UnsupportedOperation (also inherits from ValueError)
             +-- socket.error
         +-- OSError
+            +-- VMSError
             +-- WindowsError
         +-- mmap.error
     +-- select.error
@@ -206,7 +207,7 @@ The following changes are proposed:
 
 * alias both socket.error and select.error to IOError
 * alias mmap.error to OSError
-* alias WindowsError to OSError
+* alias both WindowsError and VMSError to OSError
 * alias OSError to IOError
 * coalesce EnvironmentError into IOError
 
@@ -543,6 +544,14 @@ Common errnos with select.error
 Appendix B: Survey of raised OS and IO errors
 =============================================
 
+About VMSError
+--------------
+
+VMSError is completely unused by the interpreter core and the standard
+library.  It was added as part of the OpenVMS patches submitted in 2002
+by Jean-François Piéronne [4]_; the motivation for including VMSError was that
+it could be raised by third-party packages.
+
 Interpreter core
 ----------------
 
@@ -797,6 +806,8 @@ References
    ``EnvironmentError``: `around 3000 results
    <http://www.google.com/codesearch?q=lang%3Apython%20EnvironmentError>`_
 
+.. [4] http://bugs.python.org/issue614055
+
 Copyright
 =========