NAME
        LockPubScreen -- Prevent a public screen from closing. (V36)

    SYNOPSIS
        screen = LockPubScreen( Name )
        D0                      A0

        struct screen *lockpubscreen( ubyte * );

    FUNCTION
        Prevents a public screen (or the Workbench) from closing
        while you examine it in preparation of opening a visitor window.

        The sequence you use to open a visitor window that needs to
        examine fields in the screen it is about to open on is:
                LockPubScreen()
                ... examine fields ...
                openwindow() on public screen
                unlockpubscreen()
                ... use your window ...
                closewindow()

    NOTE 
        You needn't hold the "pubscreen lock" for the duration that
        your window is opened.  LockPubScreen() basically has the
        same effect as an open visitor window: it prevents the
        screen from being closed.

        If you pass the string "Workbench" or you pass NULL and there
        is no default public screen, the Workbench screen will
        be automatically opened if it is not already present.

    INPUTS
        Name = name string for public screen or NULL for default public
        screen.  The string "Workbench" indicates the Workbench
        screen.

    RESULT
        Returns pointer to a screen, if successful, else NULL.
        The call can fail for reasons including that the named
        public screen doesn't exist or is in private state.

    BUGS

    SEE ALSO
        openwindow(), unlockpubscreen(), getscreendata()