r"""Return full path to the user-specific config dir for this application.

        "appname" is the name of application.
            If None, just the system directory is returned.
        "appauthor" (only used on Windows) is the name of the
            appauthor or distributing body for this application. Typically
            it is the owning company name. This falls back to appname. You may
            pass False to disable it.
        "version" is an optional version path element to append to the
            path. You might want to use this if you want multiple versions
            of your app to be able to run independently. If used, this
            would typically be "<major>.<minor>".
            Only applied when appname is present.
        "roaming" (boolean, default False) can be set True to use the Windows
            roaming appdata directory. That means that for users on a Windows
            network setup for roaming profiles, this user data will be
            sync'd on login. See
            <http://technet.microsoft.com/en-us/library/cc766489(WS.10).aspx>
            for a discussion of issues.

    Typical user config directories are:
        Mac OS X:               same as user_data_dir
        Unix:                   ~/.config/<AppName>     # or in $XDG_CONFIG_HOME, if defined
        Win *:                  same as user_data_dir

    For Unix, we follow the XDG spec and support $XDG_CONFIG_HOME.
    That means, by default "~/.config/<AppName>".

def user_config_dir(appname=None, appauthor=None, version=None, roaming=False):
    r"""Return full path to the user-specific config dir for this application.

        "appname" is the name of application.
            If None, just the system directory is returned.
        "appauthor" (only used on Windows) is the name of the
            appauthor or distributing body for this application. Typically
            it is the owning company name. This falls back to appname. You may
            pass False to disable it.
        "version" is an optional version path element to append to the
            path. You might want to use this if you want multiple versions
            of your app to be able to run independently. If used, this
            would typically be "<major>.<minor>".
            Only applied when appname is present.
        "roaming" (boolean, default False) can be set True to use the Windows
            roaming appdata directory. That means that for users on a Windows
            network setup for roaming profiles, this user data will be
            sync'd on login. See
            <http://technet.microsoft.com/en-us/library/cc766489(WS.10).aspx>
            for a discussion of issues.

    Typical user config directories are:
        Mac OS X:               same as user_data_dir
        Unix:                   ~/.config/<AppName>     # or in $XDG_CONFIG_HOME, if defined
        Win *:                  same as user_data_dir

    For Unix, we follow the XDG spec and support $XDG_CONFIG_HOME.
    That means, by default "~/.config/<AppName>".
    """
    if system in ["win32", "darwin"]:
        path = user_data_dir(appname, appauthor, None, roaming)
    else:
        path = os.getenv('XDG_CONFIG_HOME', os.path.expanduser("~/.config"))
        if appname:
            path = os.path.join(path, appname)
    if appname and version:
        path = os.path.join(path, version)
    return path