Implemented PEP 405 (Python virtual environments).

1 files changed, 28 insertions, 0 deletions

diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 96450c5..1ba9005 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -29,6 +29,26 @@ always available.
    command line, see the :mod:`fileinput` module.
 
 
+.. data:: base_exec_prefix
+
+   Set during Python startup, before ``site.py`` is run, to the same value as
+   :data:`exec_prefix`. If not running in a virtual environment, the values
+   will stay the same; if ``site.py`` finds that a virtual environment is in
+   use, the values of :data:`prefix` and :data:`exec_prefix` will be changed to
+   point to the virtual environment, whereas :data:`base_prefix` and
+   :data:`base_exec_prefix` will remain pointing to the base Python
+   installation (the one which the virtual environment was created from).
+
+.. data:: base_prefix
+
+   Set during Python startup, before ``site.py`` is run, to the same value as
+   :data:`prefix`. If not running in a virtual environment, the values
+   will stay the same; if ``site.py`` finds that a virtual environment is in
+   use, the values of :data:`prefix` and :data:`exec_prefix` will be changed to
+   point to the virtual environment, whereas :data:`base_prefix` and
+   :data:`base_exec_prefix` will remain pointing to the base Python
+   installation (the one which the virtual environment was created from).
+
 .. data:: byteorder
 
    An indicator of the native byte order.  This will have the value ``'big'`` on
@@ -199,6 +219,10 @@ always available.
    installed in :file:`{exec_prefix}/lib/python{X.Y}/lib-dynload`, where *X.Y*
    is the version number of Python, for example ``3.2``.
 
+   .. note:: If a virtual environment is in effect, this value will be changed
+      in ``site.py`` to point to the virtual environment. The value for the
+      Python installation will still be available, via :data:`base_exec_prefix`.
+
 
 .. data:: executable
 
@@ -775,6 +799,10 @@ always available.
    stored in :file:`{prefix}/include/python{X.Y}`, where *X.Y* is the version
    number of Python, for example ``3.2``.
 
+   .. note:: If a virtual environment is in effect, this value will be changed
+      in ``site.py`` to point to the virtual environment. The value for the
+      Python installation will still be available, via :data:`base_prefix`.
+
 
 .. data:: ps1
           ps2