Environment Variables
=====================

Open Dylan uses a variety of environment variables to control
behavior, where to look for files, or where to place output files. In
the common case, it is not necessary to set any of these variables.

``OPEN_DYLAN_TARGET_PLATFORM``:
    Used in :doc:`cross-compilation`.

``OPEN_DYLAN_USER_REGISTRIES``:
    Controls where to look for registry entries to
    find libraries. See :doc:`source-registries`.

    Defaults to looking for a directory named ``registry`` in the current
    directory, plus in the Open Dylan internal registry.

``OPEN_DYLAN_USER_ROOT``:
    The directory where build output is placed.
    This is the 'user root'.

    On Windows, see :doc:`windows`. On all other
    platforms, this defaults to ``./_build``.

``OPEN_DYLAN_USER_BUILD``:
    The directory within the 'user root' where
    things are built.

    Defaults to ``build``.