NAME
        FreeScreenBuffer -- Free a screenbuffer structure. (v39)

    SYNOPSIS
        FreeScreenBuffer( screen, screenbuffer )
                          A0      A1

        VOID FreeScreenBuffer( struct screen *, struct screenbuffer * );

    FUNCTION
        Frees a screenbuffer structure you got from allocscreenbuffer(),
        and releases associated resources.  You must call FreeScreenBuffer()
        before you close your screen.

    INPUTS
        Screen: pointer to the screen this screenbuffer is associated with.
        ScreenBuffer: pointer to a screenbuffer structure obtained from
            allocscreenbuffer().  it is safe to call this function with
            a NULL argument.  It will have no effect.

    RESULT
        None.

    NOTES
        Originally, FreeScreenBuffer() did not waitblit() before freeing
        a bitmap.  the intent was that the application should do this.
        However, as this sort of thing is easily forgotten, waitblit()
        was added in V40.  Application writers should ensure that freeing
        the buffer is safe by calling waitblit() themselves.

        The SB_SCREEN_BITMAP flag instructs allocscreenbuffer() to provide
        a screenbuffer referring to the screen's actual bitmap.  when
        you are done changing screen buffers, you must FreeScreenBuffer()
        the currently-installed screenbuffer before you close the screen.
        Intuition will recognize when FreeScreenBuffer() is called for
        the currently-installed screenbuffer, and will know to free the
        supporting structures but not the bitmap.  closescreen() will
        take care of that.

    BUGS

    SEE ALSO
        allocscreenbuffer(), changescreenbuffer(),
        graphics.library/changevpbitmap()